RELEASE-NOTES.md

picocli Release Notes

Picocli 3.9.0 (UNRELEASED)

The picocli community is pleased to announce picocli 3.9.0.

This release contains bugfixes and enhancements in the main picocli module, and adds a new module: picocli-shell-jline3.

The new module Picocli Shell JLine3 (picocli-shell-jline3) contains components and documentation for building interactive shell command line applications with JLine 3 and picocli.

This release contains API enhancements to allow customization of the usage help message:

• help section renderers can be added, replaced or removed
• help section keys to reorder sections in the usage help message
• help factory to create custom Help instances
• option order attribute to reorder options in the usage help message option list

This release also has improved heuristics to decide whether ANSI escape codes should be emitted or not.

The simplified @-file (argument file) format is now fully compatible with JCommander: empty lines are ignored and comments may start with leading whitespace.

The picocli.Autocompletion application now accepts a parameter specifying a custom factory, and returns a non-zero exit code on error, to facilitate incorporating it into the build.

Bug fixes in this release:

• @Command method options and positional parameter values are now cleared correctly when reusing a CommandLine instance
• the default exception handler now correctly respects the exit code for all exceptions

Finally, this release improves internal quality and robustness by increasing the test code coverage. About 300 tests were added to bring the total to 1300+ tests. This improved line coverage to 98% (was 88%) and complexity coverage to 98% (was 82%).

This is the forty-fifth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Help Section Renderer API

This release introduces new API to facilitate customizing the usage help message: IHelpFactory allows applications to plug in Help subclasses, and IHelpSectionRenderer allows applications to add custom sections to the usage help message, or redefine existing sections.

The usage help message is no longer hard-coded, but is now constructed from the section renderers defined in CommandLine::getHelpSectionMap (or UsageMessageSpec::sectionMap for a single CommandSpec).

By default this map contains the predefined section renderers:

// The default section renderers delegate to methods in Help for their implementation
// (using Java 8 lambda notation for brevity):
Map<String, IHelpSectionRenderer> map = new HashMap<>();
map.put(SECTION_KEY_HEADER_HEADING,         help -> help.headerHeading());
map.put(SECTION_KEY_HEADER,                 help -> help.header());

//e.g. Usage:
map.put(SECTION_KEY_SYNOPSIS_HEADING,       help -> help.synopsisHeading());

//e.g. <cmd> [OPTIONS] <subcmd> [COMMAND-OPTIONS] [ARGUMENTS]
map.put(SECTION_KEY_SYNOPSIS,               help -> help.synopsis(help.synopsisHeadingLength()));

//e.g. %nDescription:%n%n
map.put(SECTION_KEY_DESCRIPTION_HEADING,    help -> help.descriptionHeading());

//e.g. {"Converts foos to bars.", "Use options to control conversion mode."}
map.put(SECTION_KEY_DESCRIPTION,            help -> help.description());

//e.g. %nPositional parameters:%n%n
map.put(SECTION_KEY_PARAMETER_LIST_HEADING, help -> help.parameterListHeading());

//e.g. [FILE...] the files to convert
map.put(SECTION_KEY_PARAMETER_LIST,         help -> help.parameterList());

//e.g. %nOptions:%n%n
map.put(SECTION_KEY_OPTION_LIST_HEADING,    help -> help.optionListHeading());

//e.g. -h, --help   displays this help and exits
map.put(SECTION_KEY_OPTION_LIST,            help -> help.optionList());

//e.g. %nCommands:%n%n
map.put(SECTION_KEY_COMMAND_LIST_HEADING,   help -> help.commandListHeading());

//e.g.    add       adds the frup to the frooble
map.put(SECTION_KEY_COMMAND_LIST,           help -> help.commandList());
map.put(SECTION_KEY_FOOTER_HEADING,         help -> help.footerHeading());
map.put(SECTION_KEY_FOOTER,                 help -> help.footer());

Applications can add, remove or replace sections in this map. The CommandLine::getHelpSectionKeys method (or UsageMessageSpec::sectionKeys for a single CommandSpec) returns the section keys in the order that the usage help message should render the sections. The default keys are (in order):

1. SECTION_KEY_HEADER_HEADING
2. SECTION_KEY_HEADER
3. SECTION_KEY_SYNOPSIS_HEADING
4. SECTION_KEY_SYNOPSIS
5. SECTION_KEY_DESCRIPTION_HEADING
6. SECTION_KEY_DESCRIPTION
7. SECTION_KEY_PARAMETER_LIST_HEADING
8. SECTION_KEY_PARAMETER_LIST
9. SECTION_KEY_OPTION_LIST_HEADING
10. SECTION_KEY_OPTION_LIST
11. SECTION_KEY_COMMAND_LIST_HEADING
12. SECTION_KEY_COMMAND_LIST
13. SECTION_KEY_FOOTER_HEADING
14. SECTION_KEY_FOOTER

This ordering may be modified with the CommandLine::setHelpSectionKeys setter method (or UsageMessageSpec::sectionKeys(List) for a single CommandSpec).

Option order Attribute

Options are sorted alphabetically by default, but this can be switched off by specifying @Command(sortOptions = false) on the command declaration. This displays options in the order they are declared.

However, when mixing @Option methods and @Option fields, options do not reliably appear in declaration order.

The @Option(order = <int>) attribute can be used to explicitly control the position in the usage help message at which the option should be shown. Options with a lower number are shown before options with a higher number.

New Module picocli-shell-jline3

Picocli Shell JLine3 contains components and documentation for building interactive shell command line applications with JLine 3 and picocli.

This release contains the picocli.shell.jline3.PicocliJLineCompleter class. PicocliJLineCompleter is a small component that generates completion candidates to allow users to get command line TAB auto-completion for a picocli-based application running in a JLine 3 shell. It is similar to the class with the same name in the picocli.shell.jline2 package in the picocli-shell-jline2 module.

See the module's README for more details.

Improved ANSI Heuristics

This release has improved heuristics to decide whether ANSI escape codes should be emitted or not.

Support was added for the following environment variables to control enabling ANSI:

• NO_COLOR
• CLICOLOR_FORCE
• CLICOLOR
• ConEmuANSI
• ANSICON

Fixed issues

• [#574] Add picocli-shell-jline3 module. Thanks to mattirn for the pull request.
• [#567] Usage message customization API initial implementation. Thanks to Christian Helmer for the pull request.
• [#530] Added API for easily customizing the usage help message. Thanks to stechio for raising the request and productive discussions.
• [#569] Facilitate customization of the synopsis: split Help.detailedSynopsis() into protected methods.
• [#508] Annotation API: added @Option(order = <int>) attribute to allow explicit control of option ordering in the usage help message; useful when mixing methods and fields with @Option annotation.
• [#578] Add API for simplified @files argument files.
• [#573] Make simplified @files JCommander-compatible: ignore empty lines and comments starting with whitespace. Thanks to Lukáš Petrovický for the pull request with test to reproduce the issue.
• [#572] CommandSpec.addMethodSubcommands now throws picocli.CommandLine.InitializationException instead of java.lang.UnsupportedOperationException when the user object of the parent command is a java.lang.reflect.Method.
• [#581] Added support for ConEmu, ANSICON and other environment variables to improve the ANSI heuristics. Documented the heuristics in the user manual.
• [#579] Improved AutoComplete error message when not overwriting existing files.
• [#585] picocli.AutoComplete now accepts a parameter specifying a custom IFactory implementation. Thanks to Bob Tiernay for the suggestion.
• [#582] picocli.AutoComplete now returns a non-zero return code on error. Thanks to Bob Tiernay for the suggestion.
• [#570] Bugfix: Command method options and positional parameter Object values are now cleared correctly when reusing CommandLine. Thanks to Christian Helmer for the pull request.
• [#576] Bugfix: fixed StringIndexOutOfBoundsException in shell-jline2 completion when cursor was before = when option parameter was attached to option name.
• [#583] Bugfix: Default exception handler now exits on exception if exitCode was set, regardless of exception type.
• [#584] Add documentation for generating autocompletion script during a Maven build. Thanks to Bob Tiernay.
• [#586] Replace Ansi.Text.clone() with copy constructor.
• [#571] Improve test code coverage. Added ~300 tests to bring the total to 1300+ tests. Improved line coverage to 98% (was 88%) and complexity coverage to 98% (was 82%).

Deprecations

No features were deprecated in this release.

Potential breaking changes

CommandSpec.addMethodSubcommands now throws InitializationException instead of java.lang.UnsupportedOperationException when the user object of the parent command is a java.lang.reflect.Method.

AutoComplete application now prints different error message when not overwriting existing script files. This may break tests that verify the console output.

Picocli 3.8.2

The picocli community is pleased to announce picocli 3.8.2.

This release contains bugfixes only.

When running a native image with Graal, ANSI colors are now shown correctly.

This is the forty-forth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Fixed issues

• [#557] Bugfix: No colors are shown when compiling to a native image with Graal on MacOS. Thanks to Oliver Weiler for the bug report.

Deprecations

No features were deprecated in this release.

Potential breaking changes

This is a patch release and has no breaking changes.

Picocli 3.8.1

The picocli community is pleased to announce picocli 3.8.1.

This release contains bugfixes and minor enhancements.

Command methods explicitly throwing a ParametersException is now correctly handled by picocli, showing the error message and the usage help message.

This release adds support for JCommander-style argument files (one argument per line, no quoting) and better tracing.

Many thanks to the many members of the picocli community who contributed!

This is the forty-third public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Simplified Argument Files

In this argument file format every line (except comment lines) is interpreted as a single argument. Arguments containing whitespace do not need to be quoted, but it is not possible to have arguments with embedded newlines.

Set system property picocli.useSimplifiedAtFiles without a value or with value "true" (case-insensitive) to enable this simpler argument file format.

This format is similar to the way JCommander processes argument files, which makes it easier for command line applications to migrate from JCommander to picocli.

Improved Tracing

The following information has been added to the tracing output in this release:

• Version information (picocli version, java version, os version), logged at INFO level
• ANSI enabled status, logged at DEBUG level
• Log at DEBUG level when a Map or Collection binding for an option or positional parameter is initialized with a new instance
• Log at DEBUG level when parameters are being split (into how many parts, show resulting parts)

Fixed issues

• [#551] Enhancement: Add support for JCommander-style argument files (one argument per line, no quoting). Thanks to Lukáš Petrovický for the bug report and unit tests.
• [#562] Enhancement: Allow for enabling quote trimming via system property picocli.trimQuotes. Thanks to Lukáš Petrovický for the pull request.
• [#560] Enhancement: Better tracing.
• [#554] Bugfix: Convenience method error handling was broken for command methods that explicitly throw an ParameterException: InvocationTargetException hides the ParameterException. Thanks to SysLord for the bug report.
• [#553] Doc: Fix broken link to CommandLine.java source code. Thanks to Simon Legner for the pull request.
• [#563] Doc: Improve documentation for explicitly showing usage help from subcommands. Thanks to Steve Johnson for raising this issue.

Deprecations

No features were deprecated in this release.

Potential breaking changes

This is a patch release and has no breaking changes.

Picocli 3.8.0

The picocli community is pleased to announce picocli 3.8.0.

This release contains bugfixes and minor enhancements.

@Command methods now support @Mixin parameters. OverwrittenOptionException now has an accessor for the ArgSpec that was overwritten.

The ReflectionConfigGenerator tool in the picocli-codegen module now correctly generates configuration for @Mixin fields.

Many thanks to the many members of the picocli community who contributed!

This is the forty-second public release. Picocli follows semantic versioning. (This release could have been called 3.7.1 except that it has a minor additional API change, which means it cannot be called a patch release by semver rules.)

Table of Contents

• New and noteworthy
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Mixin Support in @Command Methods

@Command methods now accept @Mixin parameters. All options and positional parameters defined in the mixin class are added to the command.

Example:

class CommonParams {
    @Option(names = "-x") int x;
    @Option(names = "-y") int y;
}

class App {
    @Command
    public void doit(@Mixin CommonParams params, @Option(names = "-z") int z) {}
}

In the above example, the -x and -y options are added to the other options of the doit command.

Fixed issues

• [#525] Enhancement: Allow @Mixin parameters in @Command methods. Thanks to Paul Horn for the pull request.
• [#532] Enhancement: OverwrittenOptionException now has an accessor for the ArgSpec that was overwritten. Thanks to Steven Fontaine for the pull request.
• [#524] Enhancement/Bugfix: ReflectionConfigGenerator in picocli-codegen should generate configuration for @Mixin fields. Thanks to Paul Horn for the pull request.
• [#301] Enhancement/Bugfix: The subcommand listing now correctly renders %n as line breaks in the brief description for each subcommand. Thanks to Vlad Topala for the pull request.
• [#523] Bugfix: Array should be initialized before calling setter method. Thanks to Paul Horn for the pull request.
• [#527] Bugfix: Quoting logic did not work for some Unicode code points.
• [#531] Bugfix: Usage help should not show space between short option name and parameter (for options that only have a short name).
• [#538] Bugfix: Command methods and interface methods should pass null for unmatched primitive wrapper options.
• [#547] Bugfix: Fix infinite loop when print help. Thanks to Patrick Kuo for the pull request.
• [#528] Doc: Javadoc for xxxHandler API referred to non-existant prototypeReturnValue.
• [#545] Doc: Include mention of command methods for options using collections. Thanks to Bob Tiernay for the pull request.

Deprecations

No features were deprecated in this release.

Potential breaking changes

Help Layout

The usage help no longer shows a space between short option names and the parameter (for options that only have a short name). This may break tests that rely on the exact output format.

Before:

Usage: times [-l=<arg0>] [-r=<arg1>]
  -l= <arg0>
  -r= <arg1>

After:

Usage: times [-l=<arg0>] [-r=<arg1>]
  -l=<arg0>
  -r=<arg1>

Unmatched Primitive Wrapper Type Options

Another behavioral change is that command methods now pass in null for primitive wrapper options that were not matched on the command line. This impacts methods annotated with @Command, and interface methods annotated with @Option. Classes annotated with @Command already behaved like this and this has not changed.

This behaviour is now consistent for all annotation-based and programmatic ways of defining commands.

Picocli 3.7.0

The picocli community is pleased to announce picocli 3.7.0.

This release contains bugfixes and enhancements in the main picocli module, and adds two new modules: picocli-codegen and picocli-shell-jline2.

Picocli Code Generation (picocli-codegen) contains tools for generating source code, documentation and configuration files for picocli-based applications.

Picocli Shell JLine2 (picocli-shell-jline2) contains components and documentation for building interactive shell command line applications with JLine 2 and picocli.

Many thanks to the many members of the picocli community who contributed!

This is the forty-first public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Improved Parsing of Quoted Values

This release improves parser behaviour of quoted arguments:

• Quotes around command line parameters are now preserved by default (previously they were removed). This can be configured with CommandLine::setTrimQuotes.
• When splitting parameters, quoted strings are no longer split. This can be configured with CommandLine::setSplitQuotedStrings.

Example:

@Option(names = "-x", split = ",")
String[] parts;

Given input like below:

<command> -x a,b,"c,d,e",f,"xxx,yyy"

This results in the parts array having the following values:

a
b
"c,d,e"
f
"xxx,yyy"

New Module picocli-codegen

Picocli Code Generation contains tools for generating source code, documentation and configuration files for picocli-based applications.

This release contains the ReflectionConfigGenerator class. ReflectionConfigGenerator generates a JSON String with the program elements that will be accessed reflectively in a picocli-based application, in order to compile this application ahead-of-time into a native executable with GraalVM.

The output of ReflectionConfigGenerator is intended to be passed to the -H:ReflectionConfigurationFiles=/path/to/reflectconfig option of the native-image GraalVM utility. This allows picocli-based applications to be compiled to a native image.

See Picocli on GraalVM: Blazingly Fast Command Line Apps for details.

The module's README explains how to configure your build to generate the configuration file automatically as part of your build.

New Module picocli-shell-jline2

Picocli Shell JLine2 contains components and documentation for building interactive shell command line applications with JLine 2 and picocli.

This release contains the PicocliJLineCompleter class. PicocliJLineCompleter is a small component that generates completion candidates to allow users to get command line TAB auto-completion for a picocli-based application running in a JLine 2 shell.

See the module's README for more details.

Fixed issues

• [#503] Build: Upgrade to gradle 4.10.2.
• [#497] add module picocli-shell-jline2 for components and documentation for building interactive shell command line applications with JLine 2 and picocli.
• [#499] add module picocli-codegen for tools to generate documentation, configuration, source code and other files from a picocli model
• [#410] add ReflectionConfigGenerator class for GraalVM native-image
• [#513] Enhancement: Simplify AutoCompletion script generator code.
• [#481] Enhancement: Add @Command(usageHelpWidth = <int>) annotation attribute.
• [#379] Option with split property should not split quoted strings. Thanks to Markus Kramer for the feature request.
• [#514] Bugfix/Enhancement: picocli no longer removes opening and closing quotes around arguments by default. This is configurable with CommandLine::setTrimQuotes. Thanks to mshatalov for the bug report.
• [#509] Bugfix: Long boolean options with arity 0 should not allow parameters. Thanks to Adam Zegelin for the bug report.
• [#510] Documentation: Fix broken link for moved example files. Thanks to Anthony Keenan for the pull request.
• [#24] Documentation: Added Chinese translations of "Picocli 2.0 Do More With Less" and "Picocli 2.0 Groovy Scripts on Steroids".

Deprecations

No features were deprecated in this release.

Potential breaking changes

From this release, picocli no longer removes opening and closing quotes around arguments by default. This is configurable with CommandLine::setTrimQuotes.

Picocli 3.6.1

The picocli community is pleased to announce picocli 3.6.1.

This release contains bugfixes, minor enhancements and documentation improvements.

ANSI is automatically enabled on Windows if Jansi's AnsiConsole has been installed.

It is now possible to selectively avoid loading type converters with reflection.

Bugfix: Enum values were not rendered in ${COMPLETION-CANDIDATES} for collection type options.

Many thanks to the many members of the picocli community who contributed!

This is the fortieth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Fixed issues

• [#487] Enhancement: Auto-completion script should return from generateOptionsSwitch immediately if there is nothing to generate. Thanks to David Walluck for the pull request.
• [#483][#486] Enhancement: Improve Help.Ansi.AUTO: automatically enable ANSI on Windows if Jansi's AnsiConsole has been installed. Thanks to Philippe Charles for the pull request.
• [#491] Enhancement: Improve Help.Ansi.AUTO cygwin/msys detection on Windows.
• [#451] Enhancement: Selectively disable reflective type converter registration. Thanks to Paolo Di Tommaso for the suggestion.
• [#488] Doc: Clarify in user manual that CommandLine.setPosixClusteredShortOptionsAllowed(false) means that option parameters cannot be attached to the option name. Thanks to Maryam Ziyad for raising this.
• [#492][#493] Doc: Add section on @Command(aliases) attribute to user manual. Thanks to marinier for the pull request.
• [#494] Bugfix: Enum values were not rendered in ${COMPLETION-CANDIDATES} for collection type options.

Deprecations

No features were deprecated in this release.

Potential breaking changes

This release has no breaking changes.

Picocli 3.6.0

The picocli community is pleased to announce picocli 3.6.0.

This release contains new features, bugfixes and enhancements.

New interface: IDefaultProvider allows you to get default values from a configuration file or some other central place.

@Command Methods: From this release, methods can be annotated with @Command. The method parameters provide the command options and parameters.

Internationalization: from this release, usage help message sections and the description for options and positional parameters can be specified in a resource bundle. A resource bundle can be set via annotations and programmatically.

The error message on invalid user input has been improved.

This release also contains various improvements the the bash/zsh completion script generation to be more consistent with standard completion on these shells.

Many thanks to the many members of the picocli community who raised issues and contributed solutions!

This is the thirty-nineth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Default Provider

This release allows you to specify a default provider in the @Command annotation:

@Command(defaultValueProvider = MyDefaultProvider.class)
class MyCommand // ...

The default provider allows you to get default values from a configuration file or some other central place. Default providers need to implement the picocli.CommandLine.IDefaultValueProvider interface:

public interface IDefaultValueProvider {

    /**
     * Returns the default value for an option or positional parameter or {@code null}.
     * The returned value is converted to the type of the option/positional parameter
     * via the same type converter used when populating this option/positional
     * parameter from a command line argument.
     *
     * @param argSpec the option or positional parameter, never {@code null}
     * @return the default value for the option or positional parameter, or {@code null} if
     *       this provider has no default value for the specified option or positional parameter
     * @throws Exception when there was a problem obtaining the default value
     */
    String defaultValue(ArgSpec argSpec) throws Exception;
}

@Command Methods

From picocli 3.6, methods can be annotated with @Command. The method parameters provide the command options and parameters. For example:

class Cat {
    public static void main(String[] args) {
        CommandLine.invoke("cat", Cat.class, args);
    }

    @Command(description = "Concatenate FILE(s) to standard output.",
             mixinStandardHelpOptions = true, version = "3.6.0")
    void cat(@Option(names = {"-E", "--show-ends"}) boolean showEnds,
             @Option(names = {"-n", "--number"}) boolean number,
             @Option(names = {"-T", "--show-tabs"}) boolean showTabs,
             @Option(names = {"-v", "--show-nonprinting"}) boolean showNonPrinting,
             @Parameters(paramLabel = "FILE") File[] files) {
        // process files
    }
}

The usage help of the above command looks like this:

Usage: cat [-EhnTvV] [FILE...]
Concatenate FILE(s) to standard output.
      [FILE...]
  -E, --show-ends
  -h, --help               Show this help message and exit.
  -n, --number
  -T, --show-tabs
  -v, --show-nonprinting
  -V, --version            Print version information and exit.

See below for an example that uses a resource bundle to define usage help descriptions outside the code.

For positional parameters, the @Parameters annotation may be omitted on method parameters.

TIP: If compiled with the -parameters flag on Java 8 or higher, the paramLabel of positional parameters is obtained from the method parameter name using reflection instead of the generic arg0, arg1, etc.

Subcommand Methods

If the enclosing class is annotated with @Command, method commands are added as subcommands to the class command, unless the class command has attribute @Command(addMethodSubcommands = false). For example:

@Command(name = "git", mixinStandardHelpOptions = true, version = "picocli-3.6.0")
class Git {
    @Option(names = "--git-dir", descriptionKey = "GITDIR")
    Path path;

    @Command
    void commit(@Option(names = {"-m", "--message"}) String commitMessage,
                @Option(names = "--squash", paramLabel = "<commit>") String squash,
                @Parameters(paramLabel = "<file>") File[] files) {
        // ... implement business logic
    }
}

Use @Command(addMethodSubcommands = false) on the class @Command annotation if the @Command-annotated methods in this class should not be added as subcommands.

The usage help of the git commit command looks like this:

Usage: git commit [--squash=<commit>] [-m=<arg0>] [<file>...]
      [<file>...]
      --squash=<commit>
  -m, --message=<arg0>

Internationalization

From version 3.6, usage help message sections and the description for options and positional parameters can be specified in a resource bundle. A resource bundle can be set via annotations and programmatically.

Annotation example:

@Command(name = "i18n-demo", resourceBundle = "my.org.I18nDemo_Messages")
class I18nDemo {}

Programmatic example:

@Command class I18nDemo2 {}

CommandLine cmd = new CommandLine(new I18nDemo2());
cmd.setResourceBundle(ResourceBundle.getBundle("my.org.I18nDemo2_Messages"));

Resources for multiple commands can be specified in a single ResourceBundle. Keys and their value can be shared by multiple commands (so you don't need to repeat them for every command), but keys can be prefixed with fully qualified command name + "." to specify different values for different commands. The most specific key wins.

This is especially convenient for @Command methods where long description annotations would make the code less easy to read.

You can use a resource bundle to move the descriptions out of the code:

# shared between all commands
help = Show this help message and exit.
version = Print version information and exit.

# command-specific strings
git.usage.description = Version control system
git.GITDIR = Set the path to the repository

git.commit.usage.description = Record changes to the repository
git.commit.message = Use the given <msg> as the commit message.
git.commit.squash = Construct a commit message for use with rebase --autosquash.
git.commit.<file>[0..*] = The files to commit.

With this resource bundle, the usage help for the above git commit command looks like this:

Usage: git commit [--squash=<commit>] [-m=<arg0>] [<file>...]
Record changes to the repository
      [<file>...]         The files to commit.
      --squash=<commit>   Construct a commit message for use with rebase
                            --autosquash.
  -m, --message=<arg0>    Use the given <msg> as the commit message.

Improved Error Messages

The error messages on invalid input have been improved. For example:

Previously, if an argument could not be converted to a primitive type, the error looked like this:

Could not convert 'abc' to int for option '-num': java.lang.NumberFormatException: For input string: \"abc\"

The new error message for primitive types looks like this:

Invalid value for option '-num': 'abc' is not an int

Previously, if an argument could not be converted to an enum, the error looked like this:

Could not convert 'xyz' to TimeUnit for option '-timeUnit': java.lang.IllegalArgumentException: No enum constant java.util.concurrent.TimeUnit.xyz

The new error message for enums looks like this:

Invalid value for option '-timeUnit': expected one of [NANOSECONDS, MILLISECONDS, MICROSECONDS, SECONDS, MINUTES, HOURS, DAYS] but was 'xyz'

Fixed issues

• [#321] API: Add support for IDefaultValueProvider. Thanks to Nicolas MASSART for the pull request.
• [#416] API: Added support for @Command annotation on methods (in addition to classes). Thanks to illes for the pull request.
• [#433] API: Added method printHelpIfRequested that accepts a ColorScheme parameter. Thanks to Benny Bottema for the suggestion.
• [#441] API: Added hideParamSyntax attribute to @Option and @Parameters to allow suppressing usage syntax decorations around the param label. Thanks to Benny Bottema for the pull request.
• [#22], [#415], [#436] API: Added internationalization and localization support via resource bundles.
• [#473] Enhancement: Improved error messages for invalid input.
• [#461] Bugfix: Script auto-completion only suggests options and never default bash completions. Thanks to David Walluck for the pull request.
• [#466] Bugfix: Script auto-completion should not generate suggestions for options with arguments that have no known completions. Thanks to David Walluck for the pull request.
• [#470] Bugfix: Script auto-completion should generate suggestions for short options with arguments. Thanks to David Walluck for the pull request.
• [#444] Bugfix: Usage help shows duplicate aliases if registered with same alias multiple times.
• [#452] Doc: Add UML class diagrams to picocli Javadoc.
• [#475] Doc: Renamed module examples to picocli-examples.
• [#478] Doc: Add convenience API example to CommandLine class Javadoc.

Deprecations

No features were deprecated in this release.

Potential breaking changes

The error message displayed on invalid input is different from previous releases. This may break unit tests that expect an exact error message.

Picocli 3.5.2

The picocli community is pleased to announce picocli 3.5.2.

This is a bugfix release that fixes an issue where subcommand aliases were not recognized in some cases.

This is the thirty-eighth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#443] Bugfix: Subcommand aliases were not recognized in some cases. Thanks to K. Alex Mills for the bug report.

Deprecations

No features were deprecated in this release.

Potential breaking changes

This release has no breaking changes.

Picocli 3.5.1

The picocli community is pleased to announce picocli 3.5.1.

This is a bugfix release that fixes an issue where CommandSpec injected into Mixins had a null CommandLine.

This is the thirty-seventh public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#439] Bugfix: CommandSpec injected into Mixins had a null CommandLine. Thanks to Adam Zegelin for the bug report.

Deprecations

No features were deprecated in this release.

Potential breaking changes

This release has no breaking changes.

Picocli 3.5.0

The picocli community is pleased to announce picocli 3.5.0.

This release contains new features, bugfixes and enhancements.

Password support: for options and positional parameters marked as interactive, the user is prompted to enter a value on the console. When running on Java 6 or higher, picocli will use the Console.readPassword API so that user input is not echoed to the console.

Client code can now perform simple validation in annotated setter methods by throwing a ParameterException on invalid input.

Also, from this release, the comment character in @-files (argument files) and the end-of-options delimiter (-- by default) are configurable.

This is the thirty-sixth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Interactive Options for Passwords or Passphrases

This release introduces password support: for options and positional parameters marked as interactive, the user is prompted to enter a value on the console. When running on Java 6 or higher, picocli will use the Console.readPassword API so that user input is not echoed to the console.

Example usage:

class Login implements Callable<Object> {
    @Option(names = {"-u", "--user"}, description = "User name")
    String user;

    @Option(names = {"-p", "--password"}, description = "Passphrase", interactive = true)
    String password;

    public Object call() throws Exception {
        MessageDigest md = MessageDigest.getInstance("SHA-256");
        md.update(password.getBytes());
        System.out.printf("Hi %s, your passphrase is hashed to %s.%n", user, base64(md.digest()));
        return null;
    }
    
    private String base64(byte[] arr) { /* ... */ }
}

When this command is invoked like this:

CommandLine.call(new Login(), "-u", "user123", "-p");

Then the user will be prompted to enter a value:

Enter value for --password (Passphrase): 

When running on Java 6 or higher, the user input is not echoed to the console. After the user enters a value and presses enter, the call() method is invoked, which prints the following:

Hi user123, your passphrase is hashed to 75K3eLr+dx6JJFuJ7LwIpEpOFmwGZZkRiB84PURz6U8=.

Simple Validation in Setter Methods

Methods annotated with @Option and @Parameters can do simple input validation by throwing a ParameterException when invalid values are specified on the command line.

class ValidationExample {
    private Map<String, String> properties = new LinkedHashMap<>();
    
    @Spec private CommandSpec spec; // injected by picocli
    
    @Option(names = {"-D", "--property"}, paramLabel = "KEY=VALUE")
    public void setProperty(Map<String, String> map) {
        for (String key : map.keySet()) {
            String newValue = map.get(key);
            validateUnique(key, newValue);
            properties.put(key, newValue);
        }
    }

    private void validateUnique(String key, String newValue) {
        String existing = properties.get(key);
        if (existing != null && !existing.equals(newValue)) {
            throw new ParameterException(spec.commandLine(),
                    String.format("Duplicate key '%s' for values '%s' and '%s'.",
                    key, existing, newValue));
        }
    }
}

Prior to this release, the exception thrown from the method was wrapped in a java.lang.reflect.InvocationTargetException, which in turn was wrapped in a PicocliException, and finally in another ParameterException.

By following the recipe above and throwing a ParameterException on invalid input, all these intermediate exceptions are skipped.

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#430] Bugfix: formatting was incorrect (did not break on embedded newlines) in the subcommands list descriptions. Thanks to Benny Bottema for the bug report.
• [#431] Better support for validation in setter methods: cleaner stack trace.
• [#432] Make comment character in @-files (argument files) configurable.
• [#359] Make end-of-options delimiter configurable.
• [#82] Support reading passwords from the console with echoing disabled.

Deprecations

No features were deprecated in this release.

Potential breaking changes

This release has no breaking changes.

Picocli 3.4.0

The picocli community is pleased to announce picocli 3.4.0.

This release contains new features, bugfixes and enhancements. The parser can now ignore case when parsing arguments for an Enum option or positional parameter. New methods Help.Ansi.text(String) and Help.Ansi.string(String) assist client code in easily creating ANSI messages outside usage help and version help.

This is the thirty-fifth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#14] New API: Support enum values to be parsed in an case-insensitive way.
• [#376] New API: Help.Ansi.text(String) and Help.Ansi.string(String) help client code easily create ANSI messages outside usage help and version help.
• [#412] Enhancement: Enum constant names are now returned from ArgSpec::completionCandidates(). Thanks to Radovan Panák.
• [#417] Enhancement: Ensure bash scripts have correct line separators. Thanks to Holger Stenger.
• [#425] Enhancement: Fix autocomplete script errors in zsh. Thanks to Anthony Keenan.
• [#419] Bugfix: Default value for arrays was not rendered correctly with @{DEFAULT-VALUE}.
• [#418] Doc: Improve installation instructions for autocompletion scripts.
• [#420] Doc: Added a Quick Guide

Deprecations

No features were deprecated in this release.

Potential breaking changes

This release has no breaking changes.

Picocli 3.3.0

The picocli community is pleased to announce picocli 3.3.0.

This release contains a bugfix for the JLine TAB completion support and improves the error messages for missing required parameters and unmatched arguments.

This is the thirty-fourth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

UnmatchedArgumentException Improvements

The UnmatchedArgumentException class now has several methods that allow an application to offer suggestions for fixes to the end user.

For example:

class App {
    @Option(names = "--file") File[] files;
    @Option(names = "--find") String pattern;
    
    public static void main(String[] args) {
        App app = new App();
        try {
            new CommandLine(app).parse(args);
            // ...
            
        } catch (ParameterException ex) {
            System.err.println(ex.getMessage());
            if (!UnmatchedArgumentException.printSuggestions(ex, System.err)) { // new API
                ex.getCommandLine().usage(System.err, ansi);
            }
        }
    } 
}

If you run this class with an invalid option that is similar to an actual option, the UnmatchedArgumentException.printSuggestions method will show the actual options. For example:

<cmd> -fi

Prints this output:

Unknown option: -fi
Possible solutions: --file, --find

This is the behaviour for the CommandLine convenience methods run, call and parseWithHandlers. Note that if possible fixes are found, the usage help message is not displayed.

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#411] Bugfix: Completion candidates were only generated for the first option, not for subsequent options.
• [#409] Enhancement: Improve error message for missing required positional parameters. Thanks to Mārtiņš Kalvāns and Olle Lundberg.
• [#298] Enhancement: Add help for mistyped commands and options. Added new API to UnmatchedArgumentException. Thanks to Philippe Charles.

Deprecations

No features were deprecated in this release.

Potential breaking changes

The error message format has changed. This may impact client tests that expect a specific error message.

Picocli 3.2.0

The picocli community is pleased to announce picocli 3.2.0.

This release contains new features and enhancements:

• Improved support for Dependency Injection
• Methods can now be annotated with @Option and @Parameters
• Support for JLine-based interactive command line interfaces (completionCandidates attribute on @Option and @Parameters, and the AutoComplete.complete method)
• New @Spec annotation for injecting a command with its CommandSpec

This is the thirty-third public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Dependency Injection

This release makes integration with Dependency Injection containers extremely easy:

• CommandLine constructor now accepts a Class instance as the user object, and will delegate to the IFactory to get an instance.
• New CommandLine.run(Class<Runnable>, IFactory, ...) and CommandLine.call(Class<Callable>, IFactory, ...) methods. These work the same as the existing run and call methods except that the Runnable or Callable instance is created by the factory.

The below example shows how to create an IFactory implementation with a Guice Injector:

import com.google.inject.*;
import picocli.CommandLine.IFactory;

public class GuiceFactory implements IFactory {
    private final Injector injector = Guice.createInjector(new DemoModule());

    @Override
    public <K> K create(Class<K> aClass) throws Exception {
        return injector.getInstance(aClass);
    }

    static class DemoModule extends AbstractModule {
        @Override
        protected void configure() {
            bind(java.util.List.class).to(java.util.LinkedList.class);
            bind(Runnable.class).to(InjectionDemo.class);
        }
    }
}

Use the custom factory when creating a CommandLine instance, or when invoking the run or call convenience methods:

import javax.inject.Inject;

@Command(name = "di-demo")
public class InjectionDemo implements Runnable {
    @Inject java.util.List list;

    @Option(names = "-x") int x;

    public static void main(String[] args) {
        CommandLine.run(Runnable.class, new GuiceFactory(), args);
    }

    @Override
    public void run() {
        assert list instanceof java.util.LinkedList;
    }
}

Annotated Methods

From this release, @Option and @Parameter annotations can be added to methods as well as fields of a class.

For concrete classes, annotate "setter" methods (methods that accept a parameter) and when the option is specified on the command line, picocli will invoke the method with the value specified on the command line, converted to the type of the method parameter.

Alternatively, you may annotate "getter-like" methods (methods that return a value) on an interface, and picocli will create an instance of the interface that returns the values specified on the command line, converted to the method return type. This feature is inspired by Jewel CLI.

Annotating Methods of an Interface

The @Option and @Parameters annotations can be used on methods of an interface that return a value. For example:

interface Counter {
    @Option(names = "--count")
    int getCount();
}

You use it by specifying the class of the interface:

CommandLine cmd = new CommandLine(Counter.class); // specify a class
String[] args = new String[] {"--count", "3"};
cmd.parse(args);
Counter counter = cmd.getCommand(); // picocli created an instance
assert counter.getCount() == 3; // method returns command line value

Annotating Methods of a Concrete Class

The @Option and @Parameters annotations can be used on methods of a class that accept a parameter. For example:

class Counter {
    int count;
    
    @Option(names = "--count")
    void setCount(int count) {
        this.count = count;
    }
}

You use it by passing an instance of the class:

Counter counter = new Counter(); // the instance to populate
CommandLine cmd = new CommandLine(counter);
String[] args = new String[] {"--count", "3"};
cmd.parse(args);
assert counter.count == 3; // method was invoked with command line value

JLine Tab-Completion Support

This release adds support for JLine Tab-Completion.

Jline 2.x and 3.x is a Java library for handling console input, often used to create interactive shell applications.

Command line applications based on picocli can generate completion candidates for the command line in the JLine shell. The generated completion candidates are context sensitive, so once a subcommand is specified, only the options for that subcommand are shown, and once an option is specified, only parameters for that option are shown.

Below is an example picocli Completer implementation for JLine 2.x:

import jline.console.completer.ArgumentCompleter;
import jline.console.completer.Completer;
import picocli.AutoComplete;
import picocli.CommandLine;
import picocli.CommandLine.Model.CommandSpec;

import java.util.List;

public class PicocliJLineCompleter implements Completer {
    private final CommandSpec spec;

    public PicocliJLineCompleter(CommandSpec spec) {
        this.spec = spec;
    }

    @Override
    public int complete(String buffer, int cursor, List<CharSequence> candidates) {
        // use the jline internal parser to split the line into tokens
        ArgumentCompleter.ArgumentList list =
                new ArgumentCompleter.WhitespaceArgumentDelimiter().delimit(buffer, cursor);

        // let picocli generate completion candidates for the token where the cursor is at
        return AutoComplete.complete(spec,
                list.getArguments(),
                list.getCursorArgumentIndex(),
                list.getArgumentPosition(),
                cursor,
                candidates);
    }
}

Completion Candidates

From this release, @Options and @Parameters have a new completionCandidates attribute that can be used to generate a list of completions for this option or positional parameter. For example:

static class MyAbcCandidates extends ArrayList<String> {
    MyAbcCandidates() { super(Arrays.asList("A", "B", "C")); }
}

class ValidValuesDemo {
    @Option(names = "-o", completionCandidates = MyAbcCandidates.class)
    String option;
}

This will generate completion option values A, B and C in the generated bash auto-completion script and in JLine.

${DEFAULT-VALUE} Variable

From picocli 3.2, it is possible to embed the default values in the description for an option or positional parameter by specifying the variable ${DEFAULT-VALUE} in the description text. Picocli uses reflection to get the default values from the annotated fields.

The variable is replaced with the default value regardless of the @Command(showDefaultValues) attribute and regardless of the @Option(showDefaultValues) or @Parameters(showDefaultValues) attribute.

class DefaultValues {
    @Option(names = {"-f", "--file"},
            description = "the file to use (default: ${DEFAULT-VALUE})")
    File file = new File("config.xml");
}

CommandLine.usage(new DefaultValues(), System.out);

This produces the following usage help:

Usage: <main class> -f=<file>
  -f, --file=<file>   the file to use (default: config.xml)

${COMPLETION-CANDIDATES} Variable

Similarly, it is possible to embed the completion candidates in the description for an option or positional parameter by specifying the variable ${COMPLETION-CANDIDATES} in the description text.

This works for java enum classes and for options or positional parameters of non-enum types for which completion candidates are specified.

enum Lang { java, groovy, kotlin, javascript, frege, clojure }

static class MyAbcCandidates extends ArrayList<String> {
    MyAbcCandidates() { super(Arrays.asList("A", "B", "C")); }
}

class ValidValuesDemo {
    @Option(names = "-l", description = "Enum. Values: ${COMPLETION-CANDIDATES}")
    Lang lang = null;

    @Option(names = "-o", completionCandidates = MyAbcCandidates.class,
            description = "Candidates: ${COMPLETION-CANDIDATES}")
    String option;
}

CommandLine.usage(new ValidValuesDemo(), System.out);

This produces the following usage help:

Usage: <main class> -l=<lang> -o=<option>
  -l=<lang>     Enum. Values: java, groovy, kotlin, javascript, frege, clojure
  -o=<option>   Candidates: A, B, C

@Spec Annotation

A new @Spec annotation is now available that injects the CommandSpec model of the command into a command field.

This is useful when a command needs to use the picocli API, for example to walk the command hierarchy and iterate over its sibling commands. This complements the @ParentCommand annotation; the @ParentCommand annotation injects a user-defined command object, whereas this annotation injects a picocli class.

class InjectSpecExample implements Runnable {
   @Spec CommandSpec commandSpec;
   //...
   public void run() {
       // do something with the injected spec
   }
}
  

Lenient Parse Mode

This release adds the ability to continue parsing invalid input to the end. When collectErrors is set to true, and a problem occurs during parsing, an Exception is added to the ParseResult.errors() list and parsing continues. The default behaviour (when collectErrors is false) is to abort parsing by throwing the Exception.

This is useful when generating completion candidates on partial input, and is also useful when using picocli in languages like Clojure where idiomatic error handling does not involve throwing and catching exceptions.

When using this feature, applications are responsible for actively verifying that no errors occurred before executing the business logic. Use with care!

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#182] New Feature: Add support for annotating methods with @Option and @Parameters.
• [#393] New feature: Add support for JLine completers.
• [#389] New feature: Support 'lenient' parsing mode: don't throw Exceptions but add them to the ParseResult.errors() list and continue parsing.
• [#392] New feature: Ability to map command line arguments to picocli spec elements. Internally used for generating completion candidates.
• [#391] New feature: Add API to get completion candidates for option and positional parameter values of any type.
• [#395] New feature: Allow embedding default values anywhere in description for @Option or @Parameters.
• [#259] New Feature: Added @Spec annotation to inject CommandSpec into application field.
• [#400] Enhancement: Add run/call static methods that accept an IFactory. This allows Dependency Injection containers to provide the Runnable/Callable implementation.
• [#404] Enhancement: Ask IFactory for implementation before creating Proxy for interface. Needed for Dependency Injection.
• [#398] Enhancement: Allow @PicocliScript annotation on Groovy script @Field variables instead of just on imports.
• [#322] Enhancement: Add defaultValue attribute to @Option and @Parameters annotation.
• [#375] Enhancement: Improve ParameterIndexGapException error message. Thanks to gpettey.
• [#405] Enhancement: Add method CommandLine.getUsageMessage().
• [#406] Enhancement: Added fields to ParameterException. Thanks to David Hait.
• [#401] Doc: The user manual no longer includes the full CommandLine.java source code.

Deprecations

No features were deprecated in this release.

Potential breaking changes

This release has no breaking changes.

Picocli 3.1.0

The picocli community is pleased to announce picocli 3.1.0.

This release contains bugfixes and support for command aliases.

Picocli has a new logo! Many thanks to Reallinfo for the design!

This is the thirty-second public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Command Aliases

This release adds support for command aliases.

@Command(name = "top", subcommands = {SubCommand.class},
        description = "top level command")
static class TopLevelCommand { }

@Command(name = "sub", aliases = {"s", "sb"},
        description = "I'm a subcommand")
static class SubCommand {}

new CommandLine(new TopLevelCommand()).usage(System.out);

The above would print the following usage help message:

Usage: top [COMMAND]
top level command
Commands:
  sub, s, sb   I'm a subcommand

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#288] New feature: add support for command aliases.
• [#383] Enhancement: Reallinfo designed the new picocli logo. Amazing work, many thanks!
• [#388] Bugfix: Prevent AnnotationFormatError "Duplicate annotation for class" with @PicocliScript when the script contains classes. Thanks to Bradford Powell for the bug report.

Deprecations

No features were deprecated in this release.

Potential breaking changes

This release has no breaking changes.

Picocli 3.0.2

The picocli community is pleased to announce picocli 3.0.2.

This release contains bugfixes and enhancements for programmatic configuration.

This is the thirty-first public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#381] Bugfix: Prevent NPE when adding programmatically created subcommands to CommandLine. Thanks to Mikusch for the bug report.
• [#382] Enhancement: Subcommand name should be initialized when added to parent.

Deprecations

No features were deprecated in this release.

Potential breaking changes

This release has no breaking changes.

Picocli 3.0.1

The picocli community is pleased to announce picocli 3.0.1.

This release fixes a bug for map options and has several improvements for the usage help message, especially for subcommands.

This is the thirtieth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

From this release, the usage help synopsis of the subcommand shows not only the subcommand name but also the parent command name. For example, take the following hierarchy of subcommands.

@Command(name = "main", subcommands = {Sub.class}) class App { }
@Command(name = "sub", subcommands = {SubSub.class}) class Sub { }
@Command(name = "subsub", mixinStandardHelpOptions = true) class SubSub { }

CommandLine parser = new CommandLine(new App());
ParseResult result = parser.parseArgs("sub", "subsub", "--help");
CommandLine.printHelpIfRequested(result);

The above code prints the usage help for the subsub nested subcommand. Notice that this shows not only the subcommand name but the full command hierarchy:

Usage: main sub subsub [-hV]
  -h, --help      Show this help message and exit.
  -V, --version   Print version information and exit.

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#287] Enhancement: Subcommand help now also shows parent command name in synopsis.
• [#378] Bugfix: Map option problem when value contains '=' separator. Thanks to Markus Kramer for the bug report.
• [#377] Bugfix: Standard help options should be added last: when mixinStandardHelpOptions is set and sortOptions is false, the help options should appear after the command options in the usage help message.

Deprecations

No features were deprecated in this release.

Potential breaking changes

The usage help synopsis of the subcommand shows not only the subcommand name but also the parent command name (and parent's parent command name, up to the top-level command).

Picocli 3.0.0

The picocli community is pleased to announce picocli 3.0.0.

This release offers a programmatic API for creating command line applications, in addition to the annotations API. The programmatic API allows applications to dynamically create command line options on the fly, and also makes it possible to create idiomatic domain-specific languages for processing command line arguments, using picocli, in other JVM languages. The picocli community is proud to announce that Apache Groovy's CliBuilder DSL for command line applications has been rewritten to use the picocli programmatic API, starting from Groovy 2.5.

Another new feature in this release are Mixins. Mixins allow reusing common options, parameters and command attributes in multiple applications without copy-and-paste duplication.

This release aims to reduce boilerplate code in user applications even further with the new mixinStandardHelpOptions command attribute. Picocli adds standard usageHelp and versionHelp options to commands with this attribute. Additionally picocli now offers a HelpCommand that can be installed as a subcommand on any application command to provide usage help for the parent command or sibling subcommands.

From this release, picocli is better at following unix conventions: by default it now prints to stdout when the user requested help, and prints to stderr when the input was invalid or an unexpected error occurred. This release also gives better control over the process exit code.

A new @Unmatched annotation allows applications to easily capture unmatched arguments (arguments that could not be matched with any of the registered options or positional parameters).

Usage help message improvements: the usage help message width is now configurable, and the message layout is improved to reduce horizontal padding. Furthermore, you can now specify for individual options or positional parameters whether their default value should be shown in the description or hidden.

Finally, this release adds several options to configure parser behaviour. Picocli can now be configured to function like Apache Commons CLI, to facilitate migration from Apache Commons CLI to picocli.

This is the twenty-ninth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Programmatic API

This release offers a programmatic API for creating command line applications, in addition to the annotations API. The programmatic API allows applications to dynamically create command line options on the fly, and also makes it possible to create idiomatic domain-specific languages for processing command line arguments, using picocli, in other JVM languages. (Example: Groovy CliBuilder.)

If you have suggestions for improving the programmatic API, please raise a ticket on GitHub!

Example

CommandSpec spec = CommandSpec.create();
spec.mixinStandardHelpOptions(true); // --help and --version options
spec.addOption(OptionSpec.builder("-c", "--count")
        .paramLabel("COUNT")
        .type(int.class)
        .description("number of times to execute").build());
spec.addPositional(PositionalParamSpec.builder()
        .paramLabel("FILES")
        .type(List.class).auxiliaryTypes(File.class) // List<File>
        .description("The files to process").build());

CommandLine commandLine = new CommandLine(spec);
try {
    // see also the CommandLine.parseWithHandler(s) convenience methods
    ParseResult pr = commandLine.parseArgs(args);
    
    if (CommandLine.printHelpIfRequested(pr)) {
        return;
    }
    int count = pr.matchedOptionValue('c', 1);
    List<File> files = pr.matchedPositionalValue(0, Collections.<File>emptyList());
    for (File f : files) {
        for (int i = 0; i < count; i++) {
            System.out.printf("%d: %s%n", i, f);
        }
    }
} catch (ParseException invalidInput) {
    System.err.println(invalidInput.getMessage());
    invalidInput.getCommandLine().usage(System.err);
}

CommandSpec

CommandSpec models a command. It is the programmatic variant of the @Command annotation. It has a name and a version, both of which may be empty. It also has a UsageMessageSpec to configure aspects of the usage help message and a ParserSpec that can be used to control the behaviour of the parser.

OptionSpec and PositionalParamSpec

OptionSpec models a named option, and PositionalParamSpec models one or more positional parameters. They are the programmatic variant of the @Option and @Parameters annotations, respectively.

An OptionSpec must have at least one name, which is used during parsing to match command line arguments. Other attributes can be left empty and picocli will give them a reasonable default value. This defaulting is why OptionSpec objects are created with a builder: this allows you to specify only some attributes and let picocli initialise the other attributes. For example, if only the option’s name is specified, picocli assumes the option takes no parameters (arity = 0), and is of type boolean. Another example, if arity is larger than 1, picocli sets the type to List and the auxiliary type to String.

PositionalParamSpec objects don’t have names, but have an index range instead. A single PositionalParamSpec object can capture multiple positional parameters. The default index range is set to 0..* (all indices). A command may have multiple PositionalParamSpec objects to capture positional parameters at different index ranges. This can be useful if positional parameters at different index ranges have different data types.

Similar to OptionSpec objects, Once a PositionalParamSpec is constructed, its configuration becomes immutable, but its value can still be modified. Usually the value is set during command line parsing when a non-option command line argument is encountered at a position in its index range.

ParseResult

A ParseResult class is now available that allows applications to inspect the result of parsing a sequence of command line arguments.

This class provides methods to query whether the command line arguments included certain options or position parameters, and what the value or values of these options and positional parameters was. Both the original command line argument String value as well as a strongly typed value can be obtained.

Mixins for Reuse

Mixins are a convenient alternative to subclassing: picocli annotations from any class can be added to ("mixed in" with) another command. This includes options, positional parameters, subcommands and command attributes. Picocli autoHelp internally uses a mixin.

A mixin is a separate class with options, positional parameters, subcommands and command attributes that can be reused in other commands. Mixins can be installed by calling the CommandLine.addMixin method with an object of this class, or annotating a field in your command with @Mixin. Here is an example mixin class:

public class ReusableOptions {

    @Option(names = { "-v", "--verbose" }, description = {
        "Specify multiple -v options to increase verbosity.", "For example, `-v -v -v` or `-vvv`" })
    protected boolean[] verbosity = new boolean[0];
}

Adding Mixins Programmatically

The below example shows how a mixin can be added programmatically with the CommandLine.addMixin method.

CommandLine commandLine = new CommandLine(new MyCommand());
commandline.addMixin("myMixin", new ReusableOptions());

@Mixin Annotation

A command can also include mixins by annotating fields with @Mixin. All picocli annotations found in the mixin class are added to the command that has a field annotated with @Mixin. For example:

@Command(name = "zip", description = "Example reuse with @Mixin annotation.")
public class MyCommand {

    // adds the options defined in ReusableOptions to this command
    @Mixin
    private ReusableOptions myMixin;
}

Standard Help Options

This release introduces the mixinStandardHelpOptions command attribute. When this attribute is set to true, picocli adds a mixin to the command that adds usageHelp and versionHelp options to the command. For example:

@Command(mixinStandardHelpOptions = true, version = "auto help demo - picocli 3.0")
class AutoHelpDemo implements Runnable {

    @Option(names = "--option", description = "Some option.")
    String option;

    @Override public void run() { }
}

Commands with mixinStandardHelpOptions do not need to explicitly declare fields annotated with @Option(usageHelp = true) and @Option(versionHelp = true) any more. The usage help message for the above example looks like this:

Usage: <main class> [-hV] [--option=<option>]
      --option=<option>   Some option.
  -h, --help              Show this help message and exit.
  -V, --version           Print version information and exit.

Help Command

From this release, picocli provides a help subcommand (picocli.CommandLine.HelpCommand) that can be installed as a subcommand on any application command to provide usage help for the parent command or sibling subcommands. For example:

@Command(subcommands = HelpCommand.class)
class AutoHelpDemo implements Runnable {

    @Option(names = "--option", description = "Some option.")
    String option;

    @Override public void run() { }
}

# print help for the `maincommand` command
maincommand help

# print help for the `subcommand` command
maincommand help subcommand

For applications that want to create a custom help command, this release also introduces a new interface picocli.CommandLine.IHelpCommandInitializable that provides custom help commands with the information they need: access to the parent command and sibling commands, whether to use Ansi colors or not, and the streams to print the usage help message to.

@Unmatched Annotation

Unmatched arguments are the command line arguments that could not be assigned to any of the defined options or positional parameters. From this release, fields annotated with @Unmatched will be populated with the unmatched arguments. The field must be of type String[] or List<String>.

If picocli finds a field annotated with @Unmatched, it automatically sets unmatchedArgumentsAllowed to true so no UnmatchedArgumentException is thrown when a command line argument cannot be assigned to an option or positional parameter.

Stdout or Stderr

From picocli v3.0, the run and call convenience methods follow unix conventions: print to stdout when the user requested help, and print to stderr when the input was invalid or an unexpected error occurred.

Custom handlers can extend AbstractHandler to facilitate following this convention. AbstractHandler also provides useOut and useErr methods to allow customizing the target output streams, and useAnsi to customize the Ansi style to use:

@Command class CustomizeTargetStreamsDemo implements Runnable {
    public void run() { ... }

    public static void main(String... args) {
        CommandLine cmd = new CommandLine(new CustomizeTargetStreamsDemo());

        PrintStream myOut = getOutputPrintStream(); // custom stream to send command output to
        PrintStream myErr = getErrorPrintStream();  // custom stream for error messages

        cmd.parseWithHandlers(
                new RunLast().useOut(myOut).useAnsi(Help.Ansi.ON),
                new DefaultExceptionHandler().useErr(myErr).useAnsi(Help.Ansi.OFF),
                args);
    }
}

Exit Code Support

From picocli v3.0, the built-in parse result handlers (RunFirst, RunLast and RunAll) and exception handler (DefaultExceptionHandler) can specify an exit code. If an exit code was specified, the handler terminates the JVM with the specified status code when finished.

@Command class ExitCodeDemo implements Runnable {
    public void run() { throw new ParameterException(new CommandLine(this), "exit code demo"); }

    public static void main(String... args) {
        CommandLine cmd = new CommandLine(new ExitCodeDemo());
        cmd.parseWithHandlers(
                new RunLast().andExit(123),
                new DefaultExceptionHandler().andExit(456),
                args);
    }
}

Running this command prints the following to stderr and exits the JVM with status code 456.

exit code demo
Usage: <main class>

Custom handlers can extend AbstractHandler to inherit this behaviour.

Fine-grained ShowDefault

This release adds a showDefaultValue attribute to the @Option and @Parameters annotation. This allows you to specify for each individual option and positional parameter whether its default value should be shown in the usage help.

This attribute accepts three values:

• ALWAYS - always display the default value of this option or positional parameter, even null values, regardless what value of showDefaultValues was specified on the command
• NEVER - don't show the default value for this option or positional parameter, regardless what value of showDefaultValues was specified on the command
• ON_DEMAND - (this is the default) only show the default value for this option or positional parameter if showDefaultValues was specified on the command

The NEVER value is useful for security sensitive command line arguments like passwords. The ALWAYS value is useful when you only want to show the default value for a few arguments but not for all (in combination with @Command(showDefaultValues = false)).

Improved Usage Help Message Layout

Previously, the usage message layout had a fixed width long option name column: this column is always 24 characters, even if none of the options have a long option name.

This gave strange-looking usage help messages in some cases. For example:

@Command(name="ls")
class App {
    @Option(names = "-a", description = "display all files") boolean a;
    @Option(names = "-l", description = "use a long listing format") boolean l;
    @Option(names = "-t", description = "sort by modification time") boolean t;
}

The usage message for this example was:

Usage: ls [-alt]
  -a                          display all files
  -l                          use a long listing format
  -t                          sort by modification time

From this release, picocli adjusts the width of the long option name column to the longest name (up to max 24).

The new usage message for this example looks like this:

Usage: ls [-alt]
  -a     display all files
  -l     use a long listing format
  -t     sort by modification time

Stricter Arity Validation

Until this release, options with mandatory parameters would consume as many arguments as required, even if those arguments matched other option flags. For example:

Given a command like this:

class App {
  @Option(names = "-a", arity = "2")
  String[] a;
  
  @Option(names = "-v")
  boolean v;
}

Prior to this change, the following input would be accepted:

<command> -a 1 -v

In previous versions, picocli accepted this and assigned "1" and "-v" as the two values for the -a option. From this release, the parser notices that one of the arguments is an option and throws a MissingParameterException because not enough parameters were specified for the first option.

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#371] Fixed bug where autocompletion did not work correctly for subcommands with embedded hyphens. Thanks to Paulius Fadelis for the bug report.
• [#372] Simplify Kotlin example in user manual. Thanks to Dustin Spicuzza.

3.0.0-alpha-1

• [#245] New Feature: from 3.0, picocli offers an API for programmatic configuration.
• [#257] New Feature: new ParseResult class allows programmatic inspection of the result of parsing a sequence of command line arguments.
• [#144] New Feature: added support for mixins to allow reusing common options, positional parameters, subcommands and command attributes from any object.
• [#253] New Feature: added @Unmatched annotation for unmatched arguments.
• [#175] New Feature: mixinStandardHelpOptions attribute to install the standard --help and --version options, obviating the need for fields annotated with @Option(usageHelp = true) and @Option(versionHelp = true).
• [#175] New Feature: picocli now provides a HelpCommand that can be installed as a subcommand on any application command to provide usage help for the parent command or sibling subcommands.
• [#175] New Feature: new IHelpCommandInitializable interface facilitates construction of custom help commands.
• [#250] Enhancement: the run and call convenience methods now follow convention: print to stdout when the user requested help, print to stderr when the input was invalid or an unexpected error occurred. Added AbstractHandler to facilitate following this convention for custom parse result handlers and exception handlers.
• [#251] New Feature: exit code support. The built-in parse result handlers (RunFirst, RunLast and RunAll) and exception handler (DefaultExceptionHandler) can now optionally specify an exit code. If specified, the handler terminates the JVM with the specified status code when finished. Custom handlers can extend AbstractHandler to inherit this behaviour.
• [#262] New Feature: new showDefaultValue attribute on @Option and @Parameters gives fine-grained control over which default values to show or hide. Thanks to ymenager for the request.
• [#268] New Feature: new helpCommand attribute on @Command: if the command line arguments contain a subcommand annotated with helpCommand, the parser will not validate the required options or positional parameters of the parent command. Thanks to ymenager for the request.
• [#277] New Feature: new hidden attribute on @Command to omit the specified subcommand from the usage help message command list of the parent command. Thanks to pditommaso.
• [#159] Enhancement: make help usage message width configurable. Thanks to pditommaso.

3.0.0-alpha-2

• [#312] Enhancement and API change (against earlier alpha version): Remove AbstractSimpleParseResultHandler class and parseWithSimpleHandlers method.
• [#311] Enhancement and API change (against earlier alpha version): Simplify parseWithHandlers: removed prototypeReturnValue parameter.
• [#307] Enhancement: Provide CommandLine.usage(PrintWriter) method for testing and to facilitate GROOVY-8520 migration from commons-cli to picocli.
• [#306] Enhancement: Support generating autocompletion scripts for non-public @Command classes. Thanks to cbeams for the request.
• [#308] Enhancement: Provide API to disallow POSIX clustered short options.
• [#310] Enhancement: PicocliBaseScript should follow conventions for stdout and stderr: requested help to stdout, invalid input usage help to stderr.
• [#309] Bugfix: Tests were failing on environments that support ANSI colors.

3.0.0-alpha-3

• [#313] Enhancement and New API: add method (later removed in 3.0.0-beta-1) CommandLine::setMaxArityIsMaxTotalParams to configure the parser to use arity to limit the total number of values accumulated in an option or positional parameter.
• [#314] Enhancement and New API: add method CommandLine::setUsageHelpWidth and UsageMessageSpec::width to set the max usage help message width.
• [#316] Enhancement: Support lenient mode where annotations are optional when extracting annotations.
• [#317] Enhancement: Change semantics of ParseResult.rawOptionValue to mean values after split (but before type conversion).

3.0.0-alpha-4

• [#318] API Change: Split model IBinding into IGetter and ISetter.
• [#320] API Change: Rename parser config maxArityIsMaxTotalParams to arityRestrictsCumulativeSize. (Property was removed in 3.0.0-beta-1.)
• [#216] Enhancement: Parsed values now replace the default value of multi-value (array, Collection or Map) options and positional parameters instead of being appended to them. Thanks to wiwie for the request.
• [#261] Enhancement: Options and positional parameters with a defaultValue are never required. Thanks to ymenager for the request.
• [#315] Enhancement: Initialize ArgSpec value with defaultValue before parsing command line.
• [#263] Bugfix: positional parameter defaults were not shown in usage help message. Thanks to ymenager for the bug report.

3.0.0-alpha-5

• [#329] New API: Add parser configuration to control whether boolean flags should be toggled.
• [#328] New API: Provide getter methods on OptionSpec.Builder and PositionalParamSpec.Builder.
• [#326] New API: Add parser configuration to treat unmatched options as positional parameters.
• [#283] New API: Provide getMissing method on MissingParameterException to get a reference to the problematic options and positional parameters. Thanks to jcapsule for the suggestion.
• [#334] API Change: Rename ArgSpec.rawStringValues() to ArgSpec.stringValues().
• [#342] API Change: Prefix ParseResult methods with matched if they return only matched options/positionals.
• [#340] API Change: Rename ParseResult.optionValue(String, T) to matchedOptionValue(String, T).
• [#338] API Change: Remove ParseResult.rawOptionValue(s) and rawPositionalValue(s) methods.
• [#339] API Change: Remove ParseResult.matchedOptionValue(OptionSpec) and matchedPositionalValue(PositionalParamSpec) methods.
• [#347] API Change: Make ArgSpec.getValue, setValue and isMultiValue public methods.
• [#333] Enhancement: Added subcommand to synopsis in generated usage help. Thanks to jcapsule for the pull request.
• [#323] Enhancement: Remove dependency on java.sql package: picocli should only require the java.base module when running in Java 9.
• [#325] Enhancement: Allow custom type converter to map empty String to custom default value for empty options. Thanks to jesselong for the suggestion.
• [#303] Enhancement: Improve validation to prevent common mistakes.
• [#70] Enhancement: Positional parameters should only consume values where type conversion succeeds.
• [#346] Enhancement: Validate that arity min is never greater than max.
• [#348] Enhancement: Interpreter should call ArgSpec.setValue for every matched option or positional parameter.
• [#327] Bugfix: Default values should not cause options and positional parameters to be added to ParseResult.
• [#330] Bugfix: Interpreter should clear option's and positional parameter's stringValues list before parsing new input.
• [#335] Bugfix: Abstract class ArgSpec should not implement equals and hashCode.
• [#345] Bugfix: Stop processing varargs when cumulative size reached. (This functionality was removed in 3.0.0-beta-1.)

3.0.0-alpha-6

• [#349] New API: Add longestName() convenience method to OptionSpec.
• [#352] New API: Add method to copy all attributes of a ParserSpec to a CommandSpec.
• [#353] New API: Add method to copy all attributes of a UsageMessageSpec to a CommandSpec.
• [#343] New API: Add method Help.Ansi.Text::concat and deprecate the append method. ("Append" suggests the Text object is modified, like StringBuilder, but Text is immutable.)
• [#350] Enhancement: Improve error message for usageHelp and versionHelp validation.
• [#344] Enhancement: Don't show WARN message for unmatched args or overwritten options.
• [#351] Documentation: Improve javadoc for OptionSpec.usageHelp and versionHelp.
• [#354] Bug fix: Interpreter should reset options and positional parameters to their initial value before parsing new input.

3.0.0-beta-1

• [#364] API Change: Remove parser option arityRestrictsCumulativeSize.
• [#355] API Change: Add method ArgSpec.hasInitialValue.
• [#361] API Change: Add parser option aritySatisfiedByAttachedOptionParam for commons-cli compatibility.
• [#363] API Change: Add parser option to limit the number of parts when splitting to max arity, for compatibility with commons-cli.
• [#360] Enhancement: Dynamically adjust width of long option name column (up to max 24).

3.0.0-beta-2

• [#366] API Change: Add ArgSpec.getTypedValues() method.
• [#365] Enhancement: Stricter arity validation: options with mandatory parameters no longer consume other option flags.
• [#357] Enhancement: Improve synopsis format. Be more succinct when limitSplit is true. Support repeating groups.

Deprecations

3.0.0-alpha-1

The picocli.CommandLine.Help::Help(Object, CommandLine.Help.ColorScheme) constructor has been deprecated. Use the picocli.CommandLine.Help::Help(CommandLine.CommandSpec, CommandLine.Help.ColorScheme) constructor instead.

The picocli.CommandLine.IParseResultHandler interface has been deprecated. Use the picocli.CommandLine.IParseResultHandler2 interface instead.

The picocli.CommandLine.IExceptionHandler interface has been deprecated. Use the picocli.CommandLine.IExceptionHandler2 interface instead.

3.0.0-alpha-6

• The Help.Ansi.Text::append method is now deprecated in favour of the new concat method.

Potential breaking changes

3.0.0-alpha-1

Help API Changes

The following public fields were removed from the picocli.CommandLine.Help class. Instead, set these attributes on a CommandLine.CommandSpec object passed to any of the Help constructors.

• abbreviateSynopsis
• commandListHeading
• commandName
• customSynopsis
• description
• descriptionHeading
• footer
• footerHeading
• header
• headerHeading
• optionFields
• optionListHeading
• parameterLabelRenderer - replaced with the Help.parameterLabelRenderer() method
• parameterListHeading
• requiredOptionMarker
• separator
• showDefaultValues
• sortOptions
• synopsisHeading

Method signature changes on inner classes and interfaces of the Help class:

• Interface method CommandLine.Help.IOptionRenderer::render signature changed: CommandLine.Option and Field parameters are replaced with a single CommandLine.OptionSpec parameter.
• Interface method CommandLine.Help.IParameterRenderer::render signature changed: CommandLine.Parameters and Field parameters are replaced with a single CommandLine.PositionalParamSpec parameter.
• Interface method CommandLine.Help.IParamLabelRenderer::renderParameterLabel signature changed: Field parameter replaced with CommandLine.ArgSpec parameter.
• Class CommandLine.Help.Layout all methods changed: Field parameters replaced by CommandLine.ArgSpec, CommandLine.OptionSpec and CommandLine.PositionalParamSpec parameters.

3.0.0-alpha-2

• [#311] API change from 3.0.0-alpha-1: the parseWithHandlers methods signature changed: removed the prototypeReturnValue parameter.
• [#312] API change from 3.0.0-alpha-1: Remove AbstractSimpleParseResultHandler class and parseWithSimpleHandlers method.

3.0.0-alpha-3

• Utility method CommandLine.Help.join signature changed: now takes an additional usageHelpWidth parameter.
• Constructor CommandLine.Help.Layout(ColorScheme) signature changed: now takes an additional usageHelpWidth parameter.
• Public field CommandLine.Help.TextTable.columns is now private; added public method CommandLine.Help.TextTable.columns().
• Constructor CommandLine.Help.TextTable(Ansi) is replaced with factory method CommandLine.Help.TextTable.forDefaultColumns(Ansi, int).
• Constructor CommandLine.Help.TextTable(Ansi, int...) is replaced with factory method CommandLine.Help.TextTable.forColumnWidths(Ansi, int...).
• Constructor CommandLine.Help.TextTable(Ansi, Column...) modifier changed from public to protected.
• Added factory method CommandLine.Help.TextTable.forColumns(Ansi, Column...).
• Renamed CommandLine.MaxValuesforFieldExceededException to CommandLine.MaxValuesExceededException.

3.0.0-alpha-4

• Parsed values now replace the default value of multi-value (array, Collection or Map) options and positional parameters instead of being appended to them.
• The IBinding interface introduced in v3.0.0-alpha-1 has been replaced with two functional interfaces IGetter and ISetter.
• The UnmatchedArgsBinding factory methods introduced in v3.0.0-alpha-1 have been replaced with forStringArrayConsumer and forStringCollectionSupplier.

3.0.0-alpha-5

Changes against earlier 3.0.0-alpha versions:

• Renamed ArgSpec.rawStringValues() to ArgSpec.stringValues().
• Renamed ParseResult methods with matched if they return only matched options/positionals:
  • options to matchedOptions
  • positionalParams to matchedPositionals
  • option(char), option(String) to matchedOption
  • positional(int) to matchedPositional
  • hasOption(char), hasOption(String), hasOption(OptionSpec) to hasMatchedOption
  • hasPositional(int), hasPositional(PositionalParamSpec) to hasMatchedPositional
• Renamed ParseResult.optionValue(String, T) to matchedOptionValue(String, T), and positionalValue to matchedPositionalValue.
• Removed ParseResult::rawOptionValue(s) and rawPositionalValue(s) methods.
• Removed ParseResult.matchedOptionValue(OptionSpec) and matchedPositionalValue(PositionalParamSpec) methods.

3.0.0-beta-1

• The usage message format changed: it now dynamically adjusts the width of the long option name column. This may break tests.
• API Change: Removed parser option arityRestrictsCumulativeSize introduced in 3.0.0-alpha-3.

3.0.0-beta-2

• Stricter arity validation may break existing applications that intentionally consume arguments regardless of whether arguments are other options.

Picocli 3.0.0-beta-2

The picocli community is pleased to announce picocli 3.0.0-beta-2.

This release contains enhancements and bug fixes.

This is the twenty-eighth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Stricter Arity Validation

Until this release, options with mandatory parameters would consume as many arguments as required, even if those arguments matched other option flags. For example:

Given a command like this:

class App {
  @Option(names = "-a", arity = "2")
  String[] a;
  
  @Option(names = "-v")
  boolean v;
}

Prior to this change, the following input would be accepted:

<command> -a 1 -v

In previous versions, picocli accepted this and assigned "1" and "-v" as the two values for the -a option. From this release, the parser notices that one of the arguments is an option and throws a MissingParameterException because not enough parameters were specified for the first option.

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#366] API Change: Add ArgSpec.getTypedValues() method.
• [#365] Enhancement: Stricter arity validation: options with mandatory parameters no longer consume other option flags.
• [#357] Enhancement: Improve synopsis format. Be more succinct when limitSplit is true. Support repeating groups.

Deprecations

Potential breaking changes

• Stricter arity validation may break existing applications that intentionally consume arguments regardless of whether arguments are other options.

Picocli 3.0.0-beta-1

The picocli community is pleased to announce picocli 3.0.0-beta-1.

This release contains enhancements and bug fixes.

This is the twenty-seventh public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Previously, the usage message layout had a fixed width long option name column: this column is always 24 characters, even if none of the options have a long option name.

This gives weird-looking usage help messages in some cases. For example:

@Command(name="ls")
class App {
    @Option(names = "-a", description = "display all files") boolean a;
    @Option(names = "-l", description = "use a long listing format") boolean l;
    @Option(names = "-t", description = "sort by modification time") boolean t;
}

The usage message for this example was:

Usage: ls [-alt]
  -a                          display all files
  -l                          use a long listing format
  -t                          sort by modification time

From this release, picocli adjusts the width of the long option name column to the longest name (max 24).

The new usage message for this example looks like this:

Usage: ls [-alt]
  -a     display all files
  -l     use a long listing format
  -t     sort by modification time

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#364] API Change: Remove parser option arityRestrictsCumulativeSize.
• [#355] API Change: Add method ArgSpec.hasInitialValue.
• [#361] API Change: Add parser option aritySatisfiedByAttachedOptionParam for commons-cli compatibility.
• [#363] API Change: Add parser option to limit the number of parts when splitting to max arity, for compatibility with commons-cli.
• [#360] Enhancement: Dynamically adjust width of long option name column (up to max 24).

Deprecations

Potential breaking changes

• The usage message format changed: it now dynamically adjusts the width of the long option name column. This may break tests.
• API Change: Removed parser option arityRestrictsCumulativeSize introduced in 3.0.0-alpha-3.

Picocli 3.0.0-alpha-6

The picocli community is pleased to announce picocli 3.0.0-alpha-6.

This release contains enhancements and bug fixes.

This is the twenty-sixth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#349] New API: Add longestName() convenience method to OptionSpec.
• [#352] New API: Add method to copy all attributes of a ParserSpec to a CommandSpec.
• [#353] New API: Add method to copy all attributes of a UsageMessageSpec to a CommandSpec.
• [#343] New API: Add method Help.Ansi.Text::concat and deprecate the append method. ("Append" suggests the Text object is modified, like StringBuilder, but Text is immutable.)
• [#350] Enhancement: Improve error message for usageHelp and versionHelp validation.
• [#344] Enhancement: Don't show WARN message for unmatched args or overwritten options.
• [#351] Documentation: Improve javadoc for OptionSpec.usageHelp and versionHelp.
• [#354] Bug fix: Interpreter should reset options and positional parameters to their initial value before parsing new input.

Deprecations

• The Help.Ansi.Text::append method is now deprecated in favour of the new concat method.

See 3.0.0-alpha-1

Potential breaking changes

See also breaking changes for 3.0.0-alpha-5, 3.0.0-alpha-4, 3.0.0-alpha-3, 3.0.0-alpha-2, and 3.0.0-alpha-1.

Picocli 3.0.0-alpha-5

The picocli community is pleased to announce picocli 3.0.0-alpha-5.

This release contains enhancements and bug fixes.

This is the twenty-fifth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#329] New API: Add parser configuration to control whether boolean flags should be toggled.
• [#328] New API: Provide getter methods on OptionSpec.Builder and PositionalParamSpec.Builder.
• [#326] New API: Add parser configuration to treat unmatched options as positional parameters.
• [#283] New API: Provide getMissing method on MissingParameterException to get a reference to the problematic options and positional parameters. Thanks to jcapsule for the suggestion.
• [#334] API Change: Rename ArgSpec.rawStringValues() to ArgSpec.stringValues().
• [#342] API Change: Prefix ParseResult methods with matched if they return only matched options/positionals.
• [#340] API Change: Rename ParseResult.optionValue(String, T) to matchedOptionValue(String, T).
• [#338] API Change: Remove ParseResult.rawOptionValue(s) and rawPositionalValue(s) methods.
• [#339] API Change: Remove ParseResult.matchedOptionValue(OptionSpec) and matchedPositionalValue(PositionalParamSpec) methods.
• [#347] API Change: Make ArgSpec.getValue, setValue and isMultiValue public methods.
• [#333] Enhancement: Added subcommand to synopsis in generated usage help. Thanks to jcapsule for the pull request.
• [#323] Enhancement: Remove dependency on java.sql package: picocli should only require the java.base module when running in Java 9.
• [#325] Enhancement: Allow custom type converter to map empty String to custom default value for empty options. Thanks to jesselong for the suggestion.
• [#303] Enhancement: Improve validation to prevent common mistakes.
• [#70] Enhancement: Positional parameters should only consume values where type conversion succeeds.
• [#346] Enhancement: Validate that arity min is never greater than max.
• [#348] Enhancement: Interpreter should call ArgSpec.setValue for every matched option or positional parameter.
• [#327] Bugfix: Default values should not cause options and positional parameters to be added to ParseResult.
• [#330] Bugfix: Interpreter should clear option's and positional parameter's stringValues list before parsing new input.
• [#335] Bugfix: Abstract class ArgSpec should not implement equals and hashCode.
• [#345] Bugfix: Stop processing varargs when cumulative size reached.

Deprecations

See 3.0.0-alpha-1

Potential breaking changes

• Renamed ArgSpec.rawStringValues() to ArgSpec.stringValues().
• Renamed ParseResult methods with matched if they return only matched options/positionals:
  • options to matchedOptions
  • positionalParams to matchedPositionals
  • option(char), option(String) to matchedOption
  • positional(int) to matchedPositional
  • hasOption(char), hasOption(String), hasOption(OptionSpec) to hasMatchedOption
  • hasPositional(int), hasPositional(PositionalParamSpec) to hasMatchedPositional
• Renamed ParseResult.optionValue(String, T) to matchedOptionValue(String, T), and positionalValue to matchedPositionalValue.
• Removed ParseResult::rawOptionValue(s) and rawPositionalValue(s) methods.
• Removed ParseResult.matchedOptionValue(OptionSpec) and matchedPositionalValue(PositionalParamSpec) methods.

See also breaking changes for 3.0.0-alpha-4, 3.0.0-alpha-3, 3.0.0-alpha-2, and 3.0.0-alpha-1.

Picocli 3.0.0-alpha-4

The picocli community is pleased to announce picocli 3.0.0-alpha-4.

This release contains enhancements and bug fixes.

This is the twenty-fourth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#318] API Change: Split model IBinding into IGetter and ISetter.
• [#320] API Change: Rename parser config maxArityIsMaxTotalParams to arityRestrictsCumulativeSize.
• [#216] Enhancement: Parsed values now replace the default value of multi-value (array, Collection or Map) options and positional parameters instead of being appended to them. Thanks to wiwie for the request.
• [#261] Enhancement: Options and positional parameters with a defaultValue are never required. Thanks to ymenager for the request.
• [#315] Enhancement: Initialize ArgSpec value with defaultValue before parsing command line.
• [#263] Bugfix: positional parameter defaults were not shown in usage help message. Thanks to ymenager for the bug report.

Deprecations

See 3.0.0-alpha-1

Potential breaking changes

• Parsed values now replace the default value of multi-value (array, Collection or Map) options and positional parameters instead of being appended to them.
• The IBinding interface introduced in v3.0.0-alpha-1 has been replaced with two functional interfaces IGetter and ISetter.
• The UnmatchedArgsBinding factory methods introduced in v3.0.0-alpha-1 have been replaced with forStringArrayConsumer and forStringCollectionSupplier.

See also breaking changes for 3.0.0-alpha-3, 3.0.0-alpha-2, and 3.0.0-alpha-1.

Picocli 3.0.0-alpha-3

The picocli community is pleased to announce picocli 3.0.0-alpha-3.

This release includes changes to allow picocli to be configured to function like Apache Commons CLI, to support GROOVY-8520:

• maxArityIsMaxTotalParams parser configuration option to use arity to limit the total number of values accumulated in an option or positional parameter.
• Usage message width can now be configured programmatically.
• "Lenient" mode when extracting annotations from a class where picocli annotations are optional (to allow mixing Groovy CLI annotations in Groovy CliBuilder).
• Change semantics of ParseResult.rawOptionValue to mean values after split (but before type conversion).

See 3.0.0-alpha-1 and 3.0.0-alpha-2 for recent functional changes.

This is the twenty-third public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Max Arity Is Max Total Params

This release introduces a maxArityIsMaxTotalParams parser configuration option.

By default, the arity of an option is the number of arguments for each occurrence of the option. For example, if option -a has arity = "2", then the following is a perfectly valid command: for each occurrence of the option, two option parameters are specified.

<command> -a 1 2 -a 3 4 -a 5 6

However, if CommandLine.setMaxArityIsMaxTotalParams(true) is called first, the above example would result in a MaxValuesExceededException because the total number of values (6) exceeds the arity of 2.

Additionally, by default, when maxArityIsMaxTotalParams is false, arity is only applied before the argument is split into parts, while when maxArityIsMaxTotalParams is set to true, validation is applied after a command line argument has been split into parts.

For example, if we have an option like this:

@Option(name = "-a", arity = "1..2", split = ",") String[] values;

By default, the following input would be a valid command:

<command> -a 1,2,3

By default, the option arity tells the parser to consume 1 to 2 arguments, and the option was followed by a single parameter, "1,2,3", which is fine.

However, if maxArityIsMaxTotalParams is set to true, the above example would result in a MaxValuesExceededException because the argument is split into 3 parts, which exceeds the max arity of 2.

Promoted Features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#313] Enhancement and New API: add method CommandLine::setMaxArityIsMaxTotalParams to configure the parser to use arity to limit the total number of values accumulated in an option or positional parameter.
• [#314] Enhancement and New API: add method CommandLine::setUsageHelpWidth and UsageMessageSpec::width to set the max usage help message width.
• [#316] Enhancement: Support lenient mode where annotations are optional when extracting annotations.
• [#317] Enhancement: Change semantics of ParseResult.rawOptionValue to mean values after split (but before type conversion).

Deprecations

See 3.0.0-alpha-1

Potential breaking changes

• Utility method CommandLine.Help.join signature changed: now takes an additional usageHelpWidth parameter.
• Constructor CommandLine.Help.Layout(ColorScheme) signature changed: now takes an additional usageHelpWidth parameter.
• Public field CommandLine.Help.TextTable.columns is now private; added public method CommandLine.Help.TextTable.columns().
• Constructor CommandLine.Help.TextTable(Ansi) is replaced with factory method CommandLine.Help.TextTable.forDefaultColumns(Ansi, int).
• Constructor CommandLine.Help.TextTable(Ansi, int...) is replaced with factory method CommandLine.Help.TextTable.forColumnWidths(Ansi, int...).
• Constructor CommandLine.Help.TextTable(Ansi, Column...) modifier changed from public to protected.
• Added factory method CommandLine.Help.TextTable.forColumns(Ansi, Column...).
• Renamed CommandLine.MaxValuesforFieldExceededException to CommandLine.MaxValuesExceededException.

See 3.0.0-alpha-2. See 3.0.0-alpha-1.

Picocli 3.0.0-alpha-2

The picocli community is pleased to announce picocli 3.0.0-alpha-2.

This release includes some bug fixes and small enhancements. See 3.0.0-alpha-1 for recent functional changes.

This is the twenty-second public release. Picocli follows semantic versioning.

Fixed issues

• [#312] Enhancement and API change: Remove AbstractSimpleParseResultHandler class and parseWithSimpleHandlers method.
• [#311] Enhancement and API change: Simplify parseWithHandlers: removed prototypeReturnValue parameter.
• [#307] Enhancement: Provide CommandLine.usage(PrintWriter) method for testing and to facilitate GROOVY-8520 migration from commons-cli to picocli.
• [#306] Enhancement: Support generating autocompletion scripts for non-public @Command classes. Thanks to cbeams for the request.
• [#308] Enhancement: Provide API to disallow POSIX clustered short options.
• [#310] Enhancement: PicocliBaseScript should follow conventions for stdout and stderr: requested help to stdout, invalid input usage help to stderr.
• [#309] Bugfix: Tests were failing on environments that support ANSI colors.

Deprecations

See 3.0.0-alpha-1

Potential breaking changes

• [#311] API change from 3.0.0-alpha-1: the parseWithHandlers methods signature changed: removed the prototypeReturnValue parameter.
• [#312] API change from 3.0.0-alpha-1: Remove AbstractSimpleParseResultHandler class and parseWithSimpleHandlers method.

See 3.0.0-alpha-1

Picocli 3.0.0-alpha-1

The picocli community is pleased to announce picocli 3.0.0-alpha-1.

This release offers a programmatic API for creating command line applications, in addition to annotations. The programmatic API allows applications to dynamically create command line options on the fly, and also makes it possible to create idiomatic domain-specific languages for processing command line arguments, using picocli, in other JVM languages.

Another new feature in this release are Mixins. Mixins allow reusing common options, parameters and command attributes in multiple applications without copy-and-paste duplication.

Third, this release aims to reduce boilerplate code in user applications even further with the new mixinStandardHelpOptions command attribute. Picocli adds standard usageHelp and versionHelp options to commands with this attribute. Additionally picocli now offers a HelpCommand that can be installed as a subcommand on any application command to provide usage help for the parent command or sibling subcommands.

From this release, picocli is better at following unix conventions: print to stdout when the user requested help, and print to stderr when the input was invalid or an unexpected error occurred.

Also, this release gives better control over the process exit code.

Additionally, fields annotated with @Unmatched will be populated with the unmatched arguments.

Furthermore, this release adds a showDefaultValue attribute to the @Option and @Parameters annotation.

This is the twenty-first public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and Noteworthy

Programmatic API (INCUBATING)

This release offers a programmatic API for creating command line applications, in addition to annotations. The programmatic API allows applications to dynamically create command line options on the fly, and also makes it possible to create idiomatic domain-specific languages for processing command line arguments, using picocli, in other JVM languages.

Note that the programmatic API is incubating and the API may change in subsequent releases. If you have suggestions for improving the programmatic API, please raise a ticket on GitHub!

Example

CommandSpec spec = CommandSpec.create();
spec.mixinStandardHelpOptions(true); // usageHelp and versionHelp options
spec.addOption(OptionSpec.builder("-c", "--count")
        .paramLabel("COUNT")
        .type(int.class)
        .description("number of times to execute").build());
spec.addPositional(PositionalParamSpec.builder()
        .paramLabel("FILES")
        .type(List.class)
        .auxiliaryTypes(File.class) // List<File>
        .description("The files to process").build());
CommandLine commandLine = new CommandLine(spec);

commandLine.parseWithSimpleHandlers(new AbstractSimpleParseResultHandler() {
    public void handle(ParseResult pr) {
        int count = pr.optionValue('c', 1);
        List<File> files = pr.positionalValue(0, Collections.<File>emptyList());
        for (int i = 0; i < count; i++) {
            for (File f : files) {
                System.out.printf("%d: %s%n", i, f);
            }
        }
    }
}, args);

CommandSpec (INCUBATING)

CommandSpec models a command. It is the programmatic variant of the @Command annotation. It has a name and a version, both of which may be empty. It also has a UsageMessageSpec to configure aspects of the usage help message and a ParserSpec that can be used to control the behaviour of the parser.

OptionSpec and PositionalParamSpec (INCUBATING)

OptionSpec models a named option, and PositionalParamSpec models one or more positional parameters. They are the programmatic variant of the @Option and @Parameters annotations, respectively.

An OptionSpec must have at least one name, which is used during parsing to match command line arguments. Other attributes can be left empty and picocli will give them a reasonable default value. This defaulting is why OptionSpec objects are created with a builder: this allows you to specify only some attributes and let picocli initialise the other attributes. For example, if only the option’s name is specified, picocli assumes the option takes no parameters (arity = 0), and is of type boolean. Another example, if arity is larger than 1, picocli sets the type to List and the auxiliary type to String.

PositionalParamSpec objects don’t have names, but have an index range instead. A single PositionalParamSpec object can capture multiple positional parameters. The default index range is set to 0..* (all indices). A command may have multiple PositionalParamSpec objects to capture positional parameters at different index ranges. This can be useful if positional parameters at different index ranges have different data types.

Similar to OptionSpec objects, Once a PositionalParamSpec is constructed, its configuration becomes immutable, but its value can still be modified. Usually the value is set during command line parsing when a non-option command line argument is encountered at a position in its index range.

ParseResult (INCUBATING)

A ParseResult class is now available that allows applications to inspect the result of parsing a sequence of command line arguments.

This class provides methods to query whether the command line arguments included certain options or position parameters, and what the value or values of these options and positional parameters was. Both the original command line argument String value as well as a strongly typed value can be obtained.

Mixins for Reuse

Mixins are a convenient alternative to subclassing: picocli annotations from any class can be added to ("mixed in" with) another command. This includes options, positional parameters, subcommands and command attributes. Picocli autoHelp internally uses a mixin.

A mixin is a separate class with options, positional parameters, subcommands and command attributes that can be reused in other commands. Mixins can be installed by calling the CommandLine.addMixin method with an object of this class, or annotating a field in your command with @Mixin. Here is an example mixin class:

public class ReusableOptions {

    @Option(names = { "-v", "--verbose" }, description = {
        "Specify multiple -v options to increase verbosity.", "For example, `-v -v -v` or `-vvv`" })
    protected boolean[] verbosity = new boolean[0];
}

Adding Mixins Programmatically

The below example shows how a mixin can be added programmatically with the CommandLine.addMixin method.

CommandLine commandLine = new CommandLine(new MyCommand());
commandline.addMixin("myMixin", new ReusableOptions());

@Mixin Annotation

A command can also include mixins by annotating fields with @Mixin. All picocli annotations found in the mixin class are added to the command that has a field annotated with @Mixin. For example:

@Command(name = "zip", description = "Example reuse with @Mixin annotation.")
public class MyCommand {

    // adds the options defined in ReusableOptions to this command
    @Mixin
    private ReusableOptions myMixin;
}

Standard Help Options

This release introduces the mixinStandardHelpOptions command attribute. When this attribute is set to true, picocli adds a mixin to the command that adds usageHelp and versionHelp options to the command. For example:

@Command(mixinStandardHelpOptions = true, version = "auto help demo - picocli 3.0")
class AutoHelpDemo implements Runnable {

    @Option(names = "--option", description = "Some option.")
    String option;

    @Override public void run() { }
}

Commands with mixinStandardHelpOptions do not need to explicitly declare fields annotated with @Option(usageHelp = true) and @Option(versionHelp = true) any more. The usage help message for the above example looks like this:

Usage: <main class> [-hV] [--option=<option>]
      --option=<option>       Some option.
  -h, --help                  Show this help message and exit.
  -V, --version               Print version information and exit.

Help Command

From this release, picocli provides a help subcommand (picocli.CommandLine.HelpCommand) that can be installed as a subcommand on any application command to provide usage help for the parent command or sibling subcommands. For example:

@Command(subcommands = HelpCommand.class)
class AutoHelpDemo implements Runnable {

    @Option(names = "--option", description = "Some option.")
    String option;

    @Override public void run() { }
}

# print help for the `maincommand` command
maincommand help

# print help for the `subcommand` command
maincommand help subcommand

For applications that want to create a custom help command, this release also introduces a new interface picocli.CommandLine.IHelpCommandInitializable that provides custom help commands with the information they need: access to the parent command and sibling commands, whether to use Ansi colors or not, and the streams to print the usage help message to.

@Unmatched Annotation

From this release, fields annotated with @Unmatched will be populated with the unmatched arguments. The field must be of type String[] or List<String>.

If picocli finds a field annotated with @Unmatched, it automatically sets unmatchedArgumentsAllowed to true so no UnmatchedArgumentException is thrown when a command line argument cannot be assigned to an option or positional parameter.

Stdout or Stderr

From picocli v3.0, the run and call convenience methods follow unix conventions: print to stdout when the user requested help, and print to stderr when the input was invalid or an unexpected error occurred.

Custom handlers can extend AbstractHandler to facilitate following this convention. AbstractHandler also provides useOut and useErr methods to allow customizing the target output streams, and useAnsi to customize the Ansi style to use:

@Command class CustomizeTargetStreamsDemo implements Runnable {
    public void run() { ... }

    public static void main(String... args) {
        CommandLine cmd = new CommandLine(new CustomizeTargetStreamsDemo());

        PrintStream myOut = getOutputPrintStream(); // custom stream to send command output to
        PrintStream myErr = getErrorPrintStream();  // custom stream for error messages

        cmd.parseWithHandlers(
                new RunLast().useOut(myOut).useAnsi(Help.Ansi.ON),
                new DefaultExceptionHandler().useErr(myErr).useAnsi(Help.Ansi.OFF),
                args);
    }
}

Exit Code Support

From picocli v3.0, the built-in parse result handlers (RunFirst, RunLast and RunAll) and exception handler (DefaultExceptionHandler) can specify an exit code. If an exit code was specified, the handler terminates the JVM with the specified status code when finished.

@Command class ExitCodeDemo implements Runnable {
    public void run() { throw new ParameterException(new CommandLine(this), "exit code demo"); }

    public static void main(String... args) {
        CommandLine cmd = new CommandLine(new ExitCodeDemo());
        cmd.parseWithHandlers(
                new RunLast().andExit(123),
                new DefaultExceptionHandler().andExit(456),
                args);
    }
}

Running this command prints the following to stderr and exits the JVM with status code 456.

exit code demo
Usage: <main class>

Custom handlers can extend AbstractHandler to inherit this behaviour.

Fine-grained ShowDefault

This release adds a showDefaultValue attribute to the @Option and @Parameters annotation. This allows you to specify for each individual option and positional parameter whether its default value should be shown in the usage help.

This attribute accepts three values:

• ALWAYS - always display the default value of this option or positional parameter, even null values, regardless what value of showDefaultValues was specified on the command
• NEVER - don't show the default value for this option or positional parameter, regardless what value of showDefaultValues was specified on the command
• ON_DEMAND - (this is the default) only show the default value for this option or positional parameter if showDefaultValues was specified on the command

The NEVER value is useful for security sensitive command line arguments like passwords. The ALWAYS value is useful when you only want to show the default value for a few arguments but not for all (in combination with @Command(showDefaultValues = false)).

Promoted features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#245] New Feature: from 3.0, picocli offers an API for programmatic configuration.
• [#257] New Feature: new ParseResult class allows programmatic inspection of the result of parsing a sequence of command line arguments.
• [#144] New Feature: added support for mixins to allow reusing common options, positional parameters, subcommands and command attributes from any object.
• [#253] New Feature: added @Unmatched annotation for unmatched arguments.
• [#175] New Feature: mixinStandardHelpOptions attribute to install the standard --help and --version options, obviating the need for fields annotated with @Option(usageHelp = true) and @Option(versionHelp = true).
• [#175] New Feature: picocli now provides a HelpCommand that can be installed as a subcommand on any application command to provide usage help for the parent command or sibling subcommands.
• [#175] New Feature: new IHelpCommandInitializable interface facilitates construction of custom help commands.
• [#250] Enhancement: the run and call convenience methods now follow convention: print to stdout when the user requested help, print to stderr when the input was invalid or an unexpected error occurred. Added AbstractHandler to facilitate following this convention for custom parse result handlers and exception handlers.
• [#251] New Feature: exit code support. The built-in parse result handlers (RunFirst, RunLast and RunAll) and exception handler (DefaultExceptionHandler) can now optionally specify an exit code. If specified, the handler terminates the JVM with the specified status code when finished. Custom handlers can extend AbstractHandler to inherit this behaviour.
• [#262] New Feature: new showDefaultValue attribute on @Option and @Parameters gives fine-grained control over which default values to show or hide. Thanks to ymenager for the request.
• [#268] New Feature: new helpCommand attribute on @Command: if the command line arguments contain a subcommand annotated with helpCommand, the parser will not validate the required options or positional parameters of the parent command. Thanks to ymenager for the request.
• [#277] New Feature: new hidden attribute on @Command to omit the specified subcommand from the usage help message command list of the parent command. Thanks to pditommaso.
• [#159] Enhancement: make help usage message width configurable. Thanks to pditommaso.

Deprecations

The picocli.CommandLine.Help::Help(Object, CommandLine.Help.ColorScheme) constructor has been deprecated. Use the picocli.CommandLine.Help::Help(CommandLine.CommandSpec, CommandLine.Help.ColorScheme) constructor instead.

The picocli.CommandLine.IParseResultHandler interface has been deprecated. Use the picocli.CommandLine.IParseResultHandler2 interface instead.

The picocli.CommandLine.IExceptionHandler interface has been deprecated. Use the picocli.CommandLine.IExceptionHandler2 interface instead.

Potential breaking changes

Help API Changes

The following public fields were removed from the picocli.CommandLine.Help class. Instead, set these attributes on a CommandLine.CommandSpec object passed to any of the Help constructors.

• abbreviateSynopsis
• commandListHeading
• commandName
• customSynopsis
• description
• descriptionHeading
• footer
• footerHeading
• header
• headerHeading
• optionFields
• optionListHeading
• parameterLabelRenderer - replaced with the Help.parameterLabelRenderer() method
• parameterListHeading
• requiredOptionMarker
• separator
• showDefaultValues
• sortOptions
• synopsisHeading

Method signature changes on inner classes and interfaces of the Help class:

• Interface method CommandLine.Help.IOptionRenderer::render signature changed: CommandLine.Option and Field parameters are replaced with a single CommandLine.OptionSpec parameter.
• Interface method CommandLine.Help.IParameterRenderer::render signature changed: CommandLine.Parameters and Field parameters are replaced with a single CommandLine.PositionalParamSpec parameter.
• Interface method CommandLine.Help.IParamLabelRenderer::renderParameterLabel signature changed: Field parameter replaced with CommandLine.ArgSpec parameter.
• Class CommandLine.Help.Layout all methods changed: Field parameters replaced by CommandLine.ArgSpec, CommandLine.OptionSpec and CommandLine.PositionalParamSpec parameters.

Picocli 2.3.0

The picocli community is pleased to announce picocli 2.3.0.

This release contains bugfixes and new features.

This release introduces a new parser flag stopAtPositional to treat the first positional parameter as end-of-options, and a stopAtUnmatched parser flag to stop matching options and positional parameters as soon as an unmatched argument is encountered.

These flags are useful for applications that need to delegate part of the command line to third party commands.

This release offers better support for options with optional values, allowing applications to distinguish between cases where the option was not specified at all, and cases where the option was specified without a value.

This is the twentieth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and noteworthy

Stop At Positional

By default, positional parameters can be mixed with options on the command line, but this is not always desirable. From this release, applications can call CommandLine.setStopAtPositional(true) to force the parser to treat all values following the first positional parameter as positional parameters.

When this flag is set, the first positional parameter effectively serves as an "end of options" marker, without requiring a separate -- argument.

Stop At Unmatched

From this release, applications can call CommandLine.setStopAtUnmatched(true) to force the parser to stop interpreting options and positional parameters as soon as it encounters an unmatched argument.

When this flag is set, the first unmatched argument and all subsequent command line arguments are added to the unmatched arguments list returned by CommandLine.getUnmatchedArguments().

Optional Values

If an option is defined with arity = "0..1", it may or not have a parameter value. If such an option is specified without a value on the command line, it is assigned an empty String. If the option is not specified, it keeps its default value. For example:

class OptionalValueDemo implements Runnable {
    @Option(names = "-x", arity = "0..1", description = "optional parameter")
    String x;

    public void run() { System.out.printf("x = '%s'%n", x); }

    public static void main(String... args) {
       CommandLine.run(new OptionalValueDemo(), System.out, args);
    }
}

Gives the following results:

java OptionalValueDemo -x value
x = 'value'

java OptionalValueDemo -x
x = ''

java OptionalValueDemo
x = 'null'

Promoted features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#215] API: stopAtUnmatched flag to stop parsing on first unmatched argument. Thanks to defnull for the request.
• [#284] API: stopAtPositional flag to treat first positional parameter as end-of-options. Thanks to defnull and pditommaso for the request.
• [#279] Enhancement: assign empty String when String option was specified without value. Thanks to pditommaso for the request.
• [#285] Bugfix: Vararg positional parameters should not consume options. Thanks to pditommaso for the bug report.
• [#286] Documentation: clarify when picocli instantiates fields for options and positional parameters. Thanks to JanMosigItemis for pointing this out.

Deprecations

This release has no additional deprecations.

Potential breaking changes

This release has no breaking changes.

Picocli 2.2.2

The picocli community is pleased to announce picocli 2.2.2.

This is a bugfix release.

This is the nineteenth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and noteworthy

This is a bugfix release and does not include any new features.

Promoted features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#282] Bugfix: unmatched option heuristic did not work when there were no options to compare against. Thanks to jcapsule.

Deprecations

This release has no additional deprecations.

Potential breaking changes

This release has no breaking changes.

Picocli 2.2.1

The picocli community is pleased to announce picocli 2.2.1.

This is a bugfix release.

This is the eighteenth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and noteworthy

This is a bugfix release and does not include any new features.

Promoted features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#254] Bugfix: Starting from 2.0.3, usage help didn't render empty lines in multi-line descriptions.
• [#255] Documentation: Update Kotlin example in user manual for the new Kotlin 1.2 array literal syntax in annotations.

Deprecations

This release has no additional deprecations.

Potential breaking changes

This release has no breaking changes.

Picocli 2.2.0

The picocli community is pleased to announce picocli 2.2.

This release is a "Project Coin"-like release for picocli: small changes with a nice pay-off.

In command line applications with subcommands, options of the parent command are often intended as "global" options that apply to all the subcommands. This release introduces a new @ParentCommand annotation that makes it easy for subcommands to access such parent command options: fields of the subcommand annotated with @ParentCommand are initialized with a reference to the parent command.

This release adds support for more built-in types, so applications don't need to register custom converters for common types. The new types include Java 7 classes like java.nio.file.Path and Java 8 classes like the value classes in the java.time package. These converters are loaded using reflection and are not available when running on Java 5 or Java 6.

This release also adds a converter attribute to the @Option and @Parameter annotations. This allows a specific option or positional parameter to use a different converter than would be used by default based on the type of the field.

Furthermore, the @Command annotation now supports a versionProvider attribute. This is useful when the version of an application should be detected dynamically at runtime. For example, an implementation may return version information obtained from the JAR manifest, a properties file or some other source.

Finally, applications may now specify a custom factory for instantiating classes that were configured as annotation attributes, like subcommands, type converters and version providers.

This is the seventeenth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and noteworthy

New @ParentCommand annotation

In command line applications with subcommands, options of the top level command are often intended as "global" options that apply to all the subcommands. Prior to this release, subcommands had no easy way to access their parent command options unless the parent command made these values available in a global variable.

The @ParentCommand annotation makes it easy for subcommands to access their parent command options: subcommand fields annotated with @ParentCommand are initialized with a reference to the parent command. For example:

@Command(name = "fileutils", subcommands = List.class)
class FileUtils {

    @Option(names = {"-d", "--directory"},
            description = "this option applies to all subcommands")
    File baseDirectory;
}

@Command(name = "list")
class List implements Runnable {

    @ParentCommand
    private FileUtils parent; // picocli injects reference to parent command

    @Option(names = {"-r", "--recursive"}, 
            description = "Recursively list subdirectories")
    private boolean recursive;

    @Override
    public void run() {
        list(new File(parent.baseDirectory, "."));
    }

    private void list(File dir) {
        System.out.println(dir.getAbsolutePath());
        if (dir.isDirectory()) {
            for (File f : dir.listFiles()) {
                System.out.println(f.getAbsolutePath());
                if (f.isDirectory() && recursive) {
                    list(f);
                }
            }
        }
    }
}

More built-in types

This release adds support for more built-in types, so applications don't need to register custom converters for common types. The new types include Java 7 classes like java.nio.file.Path and Java 8 classes like the value classes in the java.time package. These converters are loaded using reflection and are not available when running on Java 5 or Java 6.

Converters for the following types were added in this release:

• java.nio.file.Path (requires Java 7 or higher)
• java.time value objects: Duration, Instant, LocalDate, LocalDateTime, LocalTime, MonthDay, OffsetDateTime, OffsetTime, Period, Year, YearMonth, ZonedDateTime, ZoneId, ZoneOffset (requires Java 8 or higher, invokes the parse method of these classes)
• java.lang.Class (for the fully qualified class name)
• java.nio.ByteOrder (for the Strings "BIG_ENDIAN" or "LITTLE_ENDIAN")
• java.util.Currency (for the ISO 4217 code of the currency)
• java.net.NetworkInterface (for the InetAddress or name of the network interface)
• java.util.TimeZoneConverter (for the ID for a TimeZone)
• java.sql.Connection (for a database url of the form jdbc:subprotocol:subname)
• java.sql.Driver (for a database URL of the form jdbc:subprotocol:subname)
• java.sql.Timestamp (for values in the "yyyy-MM-dd HH:mm:ss" or "yyyy-MM-dd HH:mm:ss.fffffffff" formats)

Option-specific Type Converters

This release adds a converter attribute to the @Option and @Parameter annotations. This allows a specific option or positional parameter to use a different converter than would be used by default based on the type of the field.

For example, you may want to convert the constant names defined in java.sql.Types to their int value for a specific field, but this should not impact any other int fields: other int fields should continue to use the default int converter that parses numeric values.

Example usage:

class App {
    @Option(names = "--sqlType", converter = SqlTypeConverter.class)
    int sqlType;
}

Example implementation:

class SqlTypeConverter implements ITypeConverter<Integer> {
    public Integer convert(String value) throws Exception {
        switch (value) {
            case "ARRAY"  : return Types.ARRAY;
            case "BIGINT" : return Types.BIGINT;
            case "BINARY" : return Types.BINARY;
            case "BIT"    : return Types.BIT;
            case "BLOB"   : return Types.BLOB;
            //...
        }
    }
}

Dynamic Version Information

From this release, the @Command annotation supports a versionProvider attribute. Applications may specify a IVersionProvider implementation in this attribute, and picocli will instantiate this class and invoke it to collect version information.

This is useful when the version of an application should be detected dynamically at runtime. For example, an implementation may return version information obtained from the JAR manifest, a properties file or some other source.

Custom version providers need to implement the picocli.CommandLine.IVersionProvider interface:

public interface IVersionProvider {
    /**
     * Returns version information for a command.
     * @return version information (each string in the array is displayed on a separate line)
     * @throws Exception an exception detailing what went wrong when obtaining version information
     */
    String[] getVersion() throws Exception;
}

The GitHub project has a manifest file-based example and a build-generated version properties file-based example version provider implementation.

Custom factory

Declaratively registered subcommands, type converters and version providers must be instantiated somehow. From this release, a custom factory can be specified when constructing a CommandLine instance. This allows full control over object creation and opens possibilities for Inversion of Control and Dependency Injection. For example:

IFactory myFactory = getCustomFactory();
CommandLine cmdLine = new CommandLine(new Git(), myFactory);

Promoted features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#247] New @ParentCommand annotation to inject a reference to the parent command into subcommand fields. Thanks to michaelpj for the request.
• [#83] Add more built-in converters. Thanks to garydgregory for the inspiration.
• [#237] Option and Positional Parameter-specific type converters. Thanks to godzsa for the request.
• [#236] Allow obtaining version information dynamically at runtime. Thanks to kcris for the request.
• [#169] Configurable factory to instantiate subcommands that are registered via annotation attributes. Thanks to kakawait for the request.
• [#252] Example version provider implementations.

Deprecations

This release has no additional deprecations.

Potential breaking changes

This release has no breaking changes.

Picocli 2.1.0

This release contains bugfixes and new features.

Users sometimes run into system limitations on the length of a command line when creating a command line with lots of options or with long arguments for options. Starting from this release, picocli supports "argument files" or "@-files". Argument files are files that themselves contain arguments to the command. When picocli encounters an argument beginning with the character `@', it expands the contents of that file into the argument list.

Secondly, this release adds support for multi-value boolean flags. A common use case where this is useful is to let users control the level of output verbosity by specifying more -v flags on the command line. For example, -v could give high-level output, -vv could show more detailed output, and -vvv could show debug-level information.

Finally, thanks to aadrian and RobertZenz, an examples subproject containing running examples has been added. (Your contributions are welcome!)

This is the sixteenth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and noteworthy

Argument Files (@-files)

An argument file can include options and positional parameters in any combination. The arguments within a file can be space-separated or newline-separated. If an argument contains embedded whitespace, put the whole argument in double or single quotes ("-f=My Files\Stuff.java").

Lines starting with # are comments and are ignored. The file may itself contain additional @-file arguments; any such arguments will be processed recursively.

Multiple @-files may be specified on the command line.

For example, suppose a file with arguments exists at /home/foo/args, with these contents:

# This line is a comment and is ignored.
ABC -option=123
'X Y Z'

A command may be invoked with the @file argument, like this:

java MyCommand @/home/foo/args

The above will be expanded to the contents of the file:

java MyCommand ABC -option=123 "X Y Z"

This feature is similar to the 'Command Line Argument File' processing supported by gcc, javadoc and javac. The documentation for these tools shows further examples.

Repeated Boolean Flags

Multi-valued boolean options are now supported. For example:

@Option(names = "-v", description = { "Specify multiple -v options to increase verbosity.",
                                      "For example, `-v -v -v` or `-vvv`"})
boolean[] verbosity;

Users may specify multiple boolean flag options without parameters. For example:

<command> -v -v -v -vvv

The above example results in six true values being added to the verbosity array.

Promoted features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#126] New feature: Support expanding argument files, also called @-files.
• [#241] New feature (enhancing [#126]): Recursively process nested @-files; allow multiple arguments per line, allow quoted arguments with embedded whitespace.
• [#217] New feature: Support repeated boolean flag options captured in multi-valued fields.
• [#223] New feature: Added examples subproject containing running examples. Thanks to aadrian and RobertZenz.
• [#68] Enhancement: Reject private final primitive fields annotated with @Option or @Parameters: because compile-time constants are inlined, updates by picocli to such fields would not be visible to the application.
• [#239] Enhancement: Improve error message when Exception thrown from Runnable/Callable.
• [#240] Bugfix: RunAll handler should return empty list, not null, when help is requested.
• [#244] Bugfix: the parser only considered help options instead of any of help, usageHelp and versionHelp to determine if missing required options can be ignored when encountering a subcommand. Thanks to mkavanagh.

Deprecations

The Range::defaultArity(Class) method is now deprecated in favour of the Range::defaultArity(Field) method introduced in v2.0.

Potential breaking changes

Private final fields that are either String or primitive types can no longer be annotated with @Option or @Parameters. Picocli will throw an InitializationException when it detects such fields, because compile-time constants are inlined, and updates by picocli to such fields would not be visible to the application.

Picocli 2.0.3

The picocli community is pleased to announce picocli 2.0.3.

This is a bugfix release that fixes a parser bug where the first argument following a clustered options was treated as a positional parameter, and removes the erroneous runtime dependency on groovy-lang that slipped in with the 2.0 release.

This release also includes a minor enhancement to support embedded newlines in usage help sections like header or descriptions. This allows Groovy applications to use triple-quoted and dollar slashy multi-line strings in usage help sections.

This is the fifteenth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and noteworthy

This is a bugfix release and does not include any new features.

Promoted features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#230] Enhancement: Support embedded newlines in usage help sections like header or descriptions. Thanks to ddimtirov.
• [#233] Bugfix: Parser bug: first argument following clustered options is treated as a positional parameter. Thanks to mgrossmann.
• [#232] Bugfix: Remove required runtime dependency on groovy-lang. Thanks to aadrian.

Deprecations

This release does not deprecate any features.

Potential breaking changes

This release does not include any breaking features.

Picocli 2.0.2

The picocli community is pleased to announce picocli 2.0.2.

This is a bugfix release that prevents an EmptyStackException from being thrown when the command line ends in a cluster of boolean options, and furthermore fixes two scripting-related minor issues.

This is the fourteenth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and noteworthy

This is a bugfix release and does not include any new features.

Promoted features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#226] Bugfix: EmptyStackException when command line ends in a cluster of boolean options. Thanks to RobertZenz.
• [#222] Bugfix: Register default converter for Object fields for better scripting support.
• [#219] Bugfix: Command line system property -Dpicocli.trace (without value) throws exception when used with Groovy.
• [#220] Enhancement: Improve tracing for positional parameters (provide detail on current position).
• [#221] Enhancement: Add documentation for Grapes bug workaround on Groovy versions before 2.4.7.

Deprecations

This release does not deprecate any features.

Potential breaking changes

This release does not include any breaking features.

Picocli 2.0.1

The picocli community is pleased to announce picocli 2.0.1.

This is a bugfix release that removes a dependency on Java 1.7 which was accidentally included.

This is the thirteenth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and noteworthy

This is a bugfix release and does not include any new features.

Promoted features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

No features have been promoted in this picocli release.

Fixed issues

• [#214] Removed a dependency on Java 1.7 that was accidentally included. Thanks to sjsajj.

Deprecations

This release does not deprecate any features.

Potential breaking changes

This release does not include any breaking features.

Picocli 2.0

The picocli community is pleased to announce picocli 2.0.

First, picocli now provides tight integration for Groovy scripts. The new @picocli.groovy.PicocliScript annotation allows Groovy scripts to use the @Command annotation, and turns a Groovy script into a picocli-based command line application. When the script is run, @Field variables annotated with @Option or @Parameters are initialized from the command line arguments before the script body is executed.

Applications with subcommands will also benefit from upgrading to picocli 2.0. The CommandLine.run and CommandLine.call methods now work for subcommands, and if more flexibility is needed, take a look at the new parseWithHandler methods. Error handling for subcommands has been improved in this release with the new ParseException.getCommandLine method.

Improved ease of use: Usage help is now printed automatically from the CommandLine.run and CommandLine.call methods and from the built-in handlers used with the parseWithHandler method.

The parser has been improved and users can now mix positional arguments with options on the command line. Previously, positional parameter had to follow the options. Important notice: To make this feature possible, the default parsing behaviour of multi-value options and parameters changed to be non-greedy by default.

Finally, this release includes many bug fixes.

This is the twelfth public release. Picocli follows semantic versioning.

Table of Contents

• New and noteworthy
  • Groovy Script Support
  • Better Subcommand Support
  • Easier To Use
  • Parser Improvements
  • Usage Help Format Improvements
• Promoted features
• Fixed issues
• Deprecations
• Potential breaking changes

New and noteworthy

Groovy Script Support

Picocli 2.0 introduces special support for Groovy scripts.

Scripts annotated with @picocli.groovy.PicocliScript are automatically transformed to use picocli.groovy.PicocliBaseScript as their base class and can also use the @Command annotation to customize parts of the usage message like command name, description, headers, footers etc.

Before the script body is executed, the PicocliBaseScript base class parses the command line and initializes @Field variables annotated with @Option or @Parameters. The script body is executed if the user input was valid and did not request usage help or version information.

// exampleScript.groovy
@Grab('info.picocli:picocli:2.0.0')
@Command(name = "myCommand", description = "does something special")
@PicocliScript
import picocli.groovy.PicocliScript
import picocli.CommandLine.Command
import picocli.CommandLine.Option
import groovy.transform.Field

@Option(names = "-x", description = "number of repetitions")
@Field int count;

@Option(names = ["-h", "--help"], usageHelp = true, description = "print this help message and exit")
@Field boolean helpRequested;

//if (helpRequested) { // not necessary: PicocliBaseScript takes care of this
//    CommandLine.usage(this, System.err); return 0;
//}
count.times {
   println "hi"
}
// the CommandLine that parsed the args is available as a property
assert this.commandLine.commandName == "myCommand"

Better Subcommand Support

New methods CommandLine::parseWithHandler were added. These methods intend to offer the same ease of use as the run and call methods, but with more flexibility and better support for nested subcommands.

The CommandLine::call and CommandLine::run now support subcommands and will execute the last subcommand specified by the user. (Previously subcommands were ignored and only the top-level command was executed.)

From this release, picocli exceptions provide a getCommandLine method that returns the command or subcommand where parsing or execution failed. Previously, if the user provided invalid input for applications with subcommands, it was difficult to pinpoint exactly which subcommand failed to parse the input.

Easier To Use

The convenience methods will automatically print usage help and version information when the user specifies options annotated with the versionHelp or usageHelp attributes.

Methods that automatically print help:

• CommandLine::call
• CommandLine::run
• CommandLine::parseWithHandler (with the built-in Run…​ handlers)
• CommandLine::parseWithHandlers (with the built-in Run…​ handlers)

Methods that do not automatically print help:

• CommandLine::parse
• CommandLine::populateCommand

Also notable: Collection and Map fields no longer require the type annotation attribute: picocli now infers the conversion target type from the generic type parameters where possible.

Parser Improvements

Positional parameters can now be mixed with options on the command line. Previously, positional parameter had to follow the options.

To make this feature possible, the default parsing behaviour of multi-value options and parameters changed to be non-greedy by default.

Usage Help Format Improvements

This release contains various bugfixes related to improving the usage help format for multi-value options and collections. For example, for Maps that don't have a paramLabel, picocli now shows key type and value type instead of the internal Java field name.

Promoted features

Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility.

The following are the features that have been promoted in this picocli release.

• Autocomplete - as of picocli 2.0, autocompletion is no longer beta.

Fixed issues

• [#207] API Change: Provide ability to find which subcommand threw a ParameterException API enhancement. Thanks to velit and AshwinJay.
• [#179] API Change to remove full JRE dependency and require only Compact Profile. Replace use of java.awt.Point with picocli.CommandLine.Help.TextTable.Cell. Thanks to webfolderio.
• [#205] API Change: CommandLine::getCommand now returns a generic type instead of Object so client code can avoid type casting.
• [#196] API Change: Option::type() and Parameters::type() now return empty array by default (was {String.class}).
• [#210] API Change: Deprecated the option help attribute in favour of the usageHelp and versionHelp attributes.
• [#115] New feature: Added new CommandLine::parseWithHandler convenience methods for commands with subcommands.
• [#130] New feature: Options and positional parameters can now be mixed on the command line.
• [#196] New feature: Infer type from collections and maps when type annotation not specified. Thanks to ddimtirov for the suggestion.
• [#197] New feature: Use type attribute to determine conversion target type instead of field type. This allows fields to be declared as interfaces or abstract types (or arrays/collections/maps of these) and via the type attribute picocli will be able to convert String arguments to concrete implementation objects.
• [#187] New feature: Added methods to programmatically get and set the command name.
• [#192] Bugfix: Default arity should be 1, not *, for array and collection options. Thanks to RobertZenz.
• [#193] Bugfix: Splitting an argument should not cause max arity to be exceeded.
• [#191] Bugfix: Arity should not limit the total number of values put in an array or collection. Thanks to RobertZenz.
• [#186] Bugfix: Confusing usage message for collection options. Thanks to AlexFalappa.
• [#181] Bugfix: Incorrect help message was displayed for short options with paramLabel when arity > 1.
• [#184] Bugfix/Enhancement: Programmatically setting the separator is now reflected in the usage help message. Thanks to defnull.
• [#200] Bugfix: Prevent NPE when command name is set to empty string or spaces. Thanks to jansohn.
• [#203] Bugfix: Empty string parameter parsed incorrectly. Thanks to AshwinJay.
• [#194] Enhancement: Usage help should show split regex for option/parameters.
• [#198] Enhancement: Usage help parameter list details should indicate arity for positional parameters.
• [#195] Enhancement: Usage help should show Map types if paramLabel not specified.
• [#183] Enhancement: Add examples to user manual for using picocli in other JVM languages. Thanks to binkley for pointing out that Kotlin may support array literals in annotations from 1.2.
• [#185] Enhancement: Exception message text for missing options should not use field names but be more descriptive and consistent with usage help. Thanks to AlexFalappa.
• [#201] Enhancement: Usage help should not show null default values. Thanks to jansohn.
• [#202] Enhancement: Java 9: add Automatic-Module-Name: info.picocli to MANIFEST.MF to make picocli play nice in the Java 9 module system.
• [#204] Enhancement: instantiate LinkedHashSet instead of HashSet for Set fields to preserve input ordering.
• [#208] Enhancement: Remove pom.xml, which was not being maintained. Picocli can only be built with gradle going forward.
• [#212] Enhancement: Improve javadoc for picocli.AutoComplete.

Deprecations

The help attribute for options is now deprecated. Please change to use usageHelp and versionHelp attributes instead. From picocli v2.0, the convenience methods will automatically print usage help and version information when requested with the versionHelp and usageHelp option attributes (but not for the help attribute).

Potential breaking changes

This release has a number of incompatible changes:

• Multi-value options (array, list and map fields) are not greedy by default any more.
• Arity is not max values: end users may specify multi-value options (array, list and map fields) an unlimited number of times.
• A single argument that is split into parts with a regex now counts as a single argument (so arity="1" won't prevent all parts from being added to the field)
• API change: replaced java.awt.Point with custom Cell class as return value type for public method Help.TextTable.putValue().
• API change: @Option.type() and @Parameters.type() now return an empty array by default (was {String.class}).
• API change: ParameterException and all subclasses now require a CommandLine object indicating the command or subcommand that the user provided invalid input for.
• The CommandLine::call and CommandLine::run now support subcommands and will execute the last subcommand specified by the user. Previously subcommands were ignored and the top-level command was executed unconditionally.

I am not happy about the disruption these changes may cause, but I felt they were needed for three reasons: the old picocli v1.0 behaviour caused ambiguity in common use cases, was inconsistent with most Unix tools, and prevented supporting mixing options with positional arguments on the command line.

To illustrate the new non-greedy behaviour, consider this example program:

class MixDemo {
  @Option(names="-o") List<String> options;
  @Parameters         List<String> positionalParams;

  public void run() {
    System.out.println("positional: " + positionalParams);
    System.out.println("options   : " + options);
  }

  public static void main(String[] args) {
    CommandLine.run(new MixDemo(), System.err, args);
  }
}

We run this program as below, where the option is followed by multiple values:

$ java MixDemo -o 1 2 3

Previously, the arguments following -o would all end up in the options list. Running the above command with picocli 1.0 would print out the following:

# (Previously, in picocli-1.0.1)
$ java MixDemo -o 1 2 3

positional: null
options   : [1, 2, 3]

From picocli 2.0, only the first argument following -o is added to the options list, the remainder is parsed as positional parameters:

# (Currently, in picocli-2.0)
$ java MixDemo -o 1 2 3

positional: [2, 3]
options   : [1]

To put multiple values in the options list in picocli 2.0, users can specify the -o option multiple times:

$ java MixDemo -o 1 -o 2 -o 3

positional: null
options   : [1, 2, 3]

Alternatively, application authors can make a multi-value option greedy in picocli v2.0 by explicitly setting a variable arity:

class Args {
    @Option(names = "-o", arity = "1..*") List<String> options;
}

(... "greedy" means consume until the next option, so not necessarily all remaining command line arguments.)

1.0.1 - Bugfix release.

Summary: zsh autocompletion bugfix

This is the eleventh public release. Picocli follows semantic versioning.

• [#178] Fixed autocompletion bug for subcommands in zsh. Autocomplete on zsh would show only the global command options even when a subcommand was specified. Autocompletion now works for nested subcommands.

1.0.0 - Bugfix and enhancements release.

Summary

New features: command line autocompletion, -Dkey=value-like Map options and parser tracing.

Non-breaking changes to support Callable commands, Map options and format specifiers in version help.

This is the tenth public release. Picocli follows semantic versioning.

Fixed issues

• [#121] New feature: command line autocompletion. Picocli can generate bash and zsh completion scripts that allow the shell to generate potential completion matches based on the @Option and @Command annotations in your application. After this script is installed, the shell will show the options and subcommands available in your java command line application, and in some cases show possible option values.
• [#67] New feature: Map options like -Dkey1=val1 -Dkey2=val2. Both key and value can be strongly typed (not just Strings).
• [#158] New feature: parser TRACING for easy troubleshooting. The trace level can be controlled with a system property.
• [#170] New feature: added call convenience method similar to run. Applications whose main business logic may throw an exception or returns a result can now implement Callable and reduce some boilerplate code.
• [#149] Parser now throws UnmatchedArgumentException for args that resemble options but are not, instead of treating like them positional parameters. Thanks to giaco777.
• [#172] Parser now throws MaxValuesforFieldExceededException when multi-valued option or parameters max arity exceeded
• [#173] Parser now throws UnmatchedArgumentException when not all positional parameters are assigned to a field
• [#171] WARN when option overwritten with different value (when isOverwrittenOptionsAllowed=true); WARN for unmatched args (when isUnmatchedArgumentsAllowed=true). Thanks to ddimtirov.
• [#164] API change: Support format patterns in version string and printVersionHelp
• [#167] API change: Change type attribute from Class to Class[]. This was needed for Map options support.
• [#168] API change: CommandLine::setSeparator method now returns this CommandLine (was void), allowing for chained method calls.
• [#156] Added example to user manual to clarify main command common usage. Thanks to nagkumar.
• [#166] Fixed bug where adjacent markup sections resulted in incorrect ANSI escape sequences
• [#174] Fixed bug where under some circumstances, unmatched parameters were added to UnmatchedParameters list twice

0.9.8 - Bugfix and enhancements release for public review. API may change.

Summary

Non-breaking changes to add better help support and better subcommand support.

Fixed issues

• [#162] Added new Version Help section to user manual; added version attribute on @Command; added CommandLine::printVersionHelp convenience method to print version information from this annotation to the console
• [#145] Added usageHelp and versionHelp attributes on @Option; added CommandLine::isUsageHelpRequested and CommandLine::isVersionHelpRequested to allow external components to detect whether usage help or version information was requested (without inspecting the annotated domain object). Thanks to kakawait.
• [#160] Added @since version in javadoc for recent API changes.
• [#157] API change: added CommandLine::getParent method to get the parent command of a subcommand. Thanks to nagkumar.
• [#152] Added support for registering subcommands declaratively with the @Command(subcommands#{...}) annotation. Thanks to nagkumar.
• [#146] Show underlying error when type conversion fails
• [#147] Toggle boolean flags instead of setting to true
• [#148] Long string in default value no longer causes infinite loop when printing usage. Thanks to smartboyathome.
• [#142] First line of long synopsis no longer overshoots 80-character usage help width. Thanks to waacc-gh.

0.9.7 - Bugfix and enhancements release for public review. API may change.

Summary

Version 0.9.7 has some breaking API changes.

Better Groovy support

It was pointed out that Groovy had trouble distinguishing between the static parse(Object, String...) method and the instance method parse(String...).

To address this, the static parse(Object, String...) method has been renamed to populateCommand(Object, String...) in version 0.9.7.

Nested subcommands

• Version 0.9.7 adds support for nested sub-subcommands
• CommandLine::parse now returns List<CommandLine> (was List<Object>)
• CommandLine::getCommands now returns Map<String, CommandLine> (was Map<String, Object>)
• renamed method CommandLine::addCommand to addSubcommand
• renamed method CommandLine::getCommands to getSubcommands

Miscellaneous

Renamed class Arity to Range since it is not just used for @Option and @Parameters arity but also for index in positional @Parameters.

Fixed issues

• [#127] Added support for nested sub-subcommands
• [#135] API change: renamed static convenience method CommandLine::parse to populateCommand
• [#134] API change: CommandLine::parse now returns List<CommandLine> (was List<Object>)
• [#133] API change: CommandLine::getCommands now returns Map<String, CommandLine> (was Map<String, Object>)
• [#133] API change: Added method CommandLine::getCommand
• [#136] API change: renamed method CommandLine::addCommand to addSubcommand;
• [#136] API change: renamed method CommandLine::getCommands to getSubcommands
• [#131] API change: Renamed class Arity to Range
• [#137] Improve validation: disallow index gap in @Parameters annotations
• [#132] Improve validation: parsing should fail when unmatched arguments remain
• [#138] Improve validation: disallow option overwriting by default
• [#129] Make "allow option overwriting" configurable
• [#140] Make "allow unmatched arguments" configurable
• [#139] Improve validation: CommandLine must be constructed with a command that has at least one of @Command, @Option or @Parameters annotation
• [#141] Bugfix: prevent NullPointerException when sorting required options/parameters

0.9.6 - Bugfix release for public review. API may change.

• [#128] Fix unexpected MissingParameterException when a help-option is supplied (bug)

0.9.5 - Bugfix and enhancements release for public review. API may change.

• [#122] API change: remove field CommandLine.ansi (enhancement)
• [#123] API change: make public Arity fields final (enhancement)
• [#124] API change: make Help fields optionFields and positionalParameterFields final and unmodifiable (enhancement)
• [#118] BumpVersion gradle task scrambles chars in manual (bug)
• [#119] Add gradle task to publish to local folder (enhancement)

0.9.4 - Bugfix release for public review. API may change.

• [#114] Replace ISO-8613-3 "true colors" with more widely supported 256-color palette (enhancement)
• [#113] Fix javadoc warnings (doc enhancement)
• [#117] The build should work for anyone checking out the project (bug)
• [#112] Improve (shorten) user manual (doc enhancement)
• [#105] Automate publishing to JCentral & Maven Central

0.9.3 - Bugfix release for public review. API may change.

• [#90] Automate release
• [#111] Improve picocli.Demo (enhancement)
• [#110] Fix javadoc for parse(String...) return value (doc enhancement)
• [#108] Improve user manual (doc enhancement)
• [#109] run convenience method should accept PrintStream (enhancement)

0.9.2 - Bugfix release for public review. API may change.

• [#106] MissingParameterException not thrown for missing mandatory @Parameters when options are specified
• [#104] Investigate why colors don't show by default on Cygwin

0.9.1 - Bugfix release for public review. API may change.

• [#103] Replace javadoc occurences of ASCII with ANSI. (doc bug)
• [#102] Move ColorScheme inside Ansi class (enhancement question wontfix)
• [#101] Cosmetics: indent Default: <value> by 2 spaces (enhancement)
• [#100] Improve error message for DuplicateOptionAnnotationsException (enhancement)
• [#99] MissingRequiredParams error shows optional indexed Parameters (bug)
• [#98] MissingRequiredParams error shows indexed Parameters in wrong order when not declared in index order (bug)
• [#97] Fix compiler warnings (bug)
• [#96] Synopsis shows indexed Parameters in wrong order when subclassing for reuse (bug)
• [#95] EmptyStackException when no args are passed to object annotated with Parameters (bug)
• [#94] heading fields are not inherited when subclassing for reuse (bug)
• [#93] Only option fields are set accessible, not parameters fields (bug)
• [#91] Syntax highlighting in manual source blocks (doc enhancement)

0.9.0 (was 0.4.0) - User Manual and API Changes. Initial public release.

• [#89] Improve error message for missing required options and parameters (enhancement)
• [#88] Code cleanup (enhancement)
• [#87] Add CommandLine.usage methods with a ColorScheme parameter (enhancement)
• [#86] Work around issue on Windows (Jansi?) where style OFF has no effect (bug)
• [#85] Javadoc for Ansi classes (doc)
• [#84] System property to let end users set color scheme (enhancement)
• [#81] Improve README (doc enhancement)
• [#80] Support customizable Ansi color scheme (enhancement)
• [#79] Approximate istty() by checking System.console() != null (enhancement)
• [#78] Add method CommandLine.setUsageWidth(int) (enhancement wontfix)
• [#77] Replace PicoCLI in javadoc with picocli (doc enhancement)
• [#76] @Parameters javadoc is out of date (bug doc)
• [#75] The default value for the showDefaultValues attribute should be false (bug)
• [#74] rename attribute valueLabel to paramLabel (enhancement)
• [#73] Remove @Parameters synopsis attribute enhancement)
• [#72] numeric parameter conversion should parse as decimal (bug enhancement)
• [#71] Allow multiple values for an option -pA,B,C or -q="A B C" (enhancement)
• [#66] Support ansi coloring (doc enhancement)
• [#65] Consider removing the required Option attribute (enhancement question wontfix)
• [#64] Test that boolean options with arity=1 throw MissingParameterException when no value exists (not ParameterException) (bug QA)
• [#35] Allow users to express arity as a range: 0..* or 1..3 (remove "varargs" attribute) (enhancement)
• [#30] Test & update manual for exceptions thrown from custom type converters (doc QA)
• [#26] Ergonomic API - convenience method to parse & run an app (duplicate enhancement)
• [#12] Create comparison feature table with prior art (doc)
• [#11] Write user manual (doc in-progress)
• [#6] Array field values should be preserved (like Collections) and new values appended (enhancement)
• [#4] Should @Option and @Parameters have listConverter attribute instead of elementType? (enhancement question wontfix)

0.3.0 - Customizable Usage Help

• [#69] Improve TextTable API (enhancement question)
• [#63] Unify @Option and @Parameters annotations (enhancement wontfix)
• [#59] Support declarative API for customizing usage help message (enhancement wontfix)
• [#58] Add unit tests for ShortestFirst comparator (QA)
• [#57] Consider using @Usage separator for parsing as well as for usage help (enhancement)
• [#56] Add unit tests for customizable option parameter name and positional parameter name (QA)
• [#55] Add unit tests for detailed Usage line (QA)
• [#54] Add unit tests for DefaultLayout (QA)
• [#53] Add unit tests for DefaultParameterRenderer (QA)
• [#52] Add unit tests for DefaultOptionRenderer (QA)
• [#51] Add unit tests for MinimalOptionRenderer (QA)
• [#50] Add unit tests for Arity (QA)
• [#49] Detailed usage header should cluster boolean options (enhancement)
• [#48] Show positional parameters details in TextTable similar to option details (enhancement)
• [#47] Reduce API surface for usage Help (enhancement)
• [#44] Support detailed Usage line instead of generic Usage <main> [option] [parameters] (enhancement)
• [#43] Generated help message should show parameter default value (except for boolean fields) (enhancement)
• [#42] Show option parameter in generated help (use field name or field type?) (enhancement)
• [#41] Required options should be visually distinct from optional options in usage help details (enhancement)
• [#40] Test SortByShortestOptionName (QA)
• [#39] Test that first declared option is selected by ShortestFirst comparator if both equally short (QA)
• [#38] Test DefaultRenderer chooses shortest option name in left-most field (QA)
• [#37] Consider returning a list of Points from TextTable::putValue (enhancement wontfix)
• [#36] javadoc ILayout, IRenderer, DefaultLayout, DefaultRenderer (doc)
• [#34] Usage should not show options if no options exist (enhancement)
• [#32] Support customizable user help format. (enhancement)
• [#31] Add test for recognizing clustered short option when parsing varargs array (bug QA)
• [#27] Support git-like commands (enhancement)
• [#8] Add positional @Parameter annotation (enhancement)
• [#7] Implement online usage help (enhancement)
• [#5] Rename description attribute to helpText or usage (enhancement wontfix)

0.2.0 - Vararg Support

• [#25] Use Integer.decode(String) rather than Integer.parseInt (enhancement)
• [#23] @Option should not greedily consume args if varargs=false (bug)

0.1.0 - Basic Option and Parameter Parsing

• [#20] add test where option name is "-p", give it input "-pa-p" (QA)
• [#19] Improve error message for type conversion: include field name (and option name?) (enhancement)
• [#18] test superclass bean and child class bean where child class field shadows super class and have different annotation Option name (QA)
• [#17] Test superclass bean and child class bean where child class field shadows super class and have same annotation Option name (invalid QA)
• [#16] Test arity > 1 for single-value fields (int, File, ...) (QA)
• [#13] Test for enum type conversation (QA)
• [#3] Interpreter should set helpRequested=false before parse() (bug)
• [#2] Test that separators other than '=' can be configured (QA)
• [#1] Test with other option prefixes than '-' (QA)