chore: create pre-commit file

Similar to bazelbuild/examples#310
This ensures that contributors outside google3 have a means to easily make buildifier-clean commits.
It is purely opt-in, and we assume that google3 users will have buildifier run for them in another way.

.pre-commit-config.yaml

@@ -0,0 +1,12 @@
+# See CONTRIBUTING.md for instructions.
+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
+
+repos:
+  # Check formatting and lint for starlark code
+  - repo: https://github.com/keith/pre-commit-buildifier
+    rev: 6.3.3
+    hooks:
+      - id: buildifier
+        args: ["-mode=fix", "-lint=fix"]
+      - id: buildifier-lint

BUILD

@@ -12,12 +12,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+load("@rules_license//:version.bzl", "version")
 load("@rules_license//rules:license.bzl", "license")
 load("@rules_license//rules:package_info.bzl", "package_info")
-load("@rules_license//:version.bzl", "version")
 
 package(
-    default_applicable_licenses = [":license", ":package_info"],
+    default_applicable_licenses = [
+        ":license",
+        ":package_info",
+    ],
     default_visibility = ["//visibility:public"],
 )
 
@@ -38,7 +41,10 @@ package_info(
 )
 
 exports_files(
-    ["LICENSE", "WORKSPACE"],
+    [
+        "LICENSE",
+        "WORKSPACE",
+    ],
     visibility = ["//visibility:public"],
 )
 
@@ -55,9 +61,9 @@ filegroup(
         "*.bzl",
         "*.md",
     ]) + [
-        "MODULE.bazel",
         "BUILD",
         "LICENSE",
+        "MODULE.bazel",
         "WORKSPACE.bzlmod",
     ],
     visibility = ["//distro:__pkg__"],

WORKSPACE

@@ -20,27 +20,27 @@ workspace(name = "rules_license")
 # If you want to use any of the reporting or SBOM tools, and you are using a
 # WORKSPACE file instead of bzlmod, they you must explicitly depend on
 # rules_python in your WORKSPACE.
- 
+
 ### INTERNAL ONLY - lines after this are not included in the release packaging.
 
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
 http_archive(
-   name = "rules_python",
-   sha256 = "ffc7b877c95413c82bfd5482c017edcf759a6250d8b24e82f41f3c8b8d9e287e",
-   strip_prefix = "rules_python-0.19.0",
-   urls = [
-       "https://github.com/bazelbuild/rules_python/releases/download/0.19.0/rules_python-0.19.0.tar.gz",
-   ],
+    name = "rules_python",
+    sha256 = "ffc7b877c95413c82bfd5482c017edcf759a6250d8b24e82f41f3c8b8d9e287e",
+    strip_prefix = "rules_python-0.19.0",
+    urls = [
+        "https://github.com/bazelbuild/rules_python/releases/download/0.19.0/rules_python-0.19.0.tar.gz",
+    ],
 )
 
 http_archive(
     name = "rules_pkg",
+    sha256 = "eea0f59c28a9241156a47d7a8e32db9122f3d50b505fae0f33de6ce4d9b61834",
     urls = [
         "https://mirror.bazel.build/github.com/bazelbuild/rules_pkg/releases/download/0.8.0/rules_pkg-0.8.0.tar.gz",
         "https://github.com/bazelbuild/rules_pkg/releases/download/0.8.0/rules_pkg-0.8.0.tar.gz",
     ],
-    sha256 = "eea0f59c28a9241156a47d7a8e32db9122f3d50b505fae0f33de6ce4d9b61834",
 )
 
 load("@rules_pkg//:deps.bzl", "rules_pkg_dependencies")

distro/BUILD

@@ -12,13 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-load("//:version.bzl", "version")
 load("@rules_pkg//pkg:pkg.bzl", "pkg_tar")
 load("@rules_pkg//pkg/releasing:defs.bzl", "print_rel_notes")
+load("//:version.bzl", "version")
 
 package(
-    default_visibility = ["//visibility:public"],
     default_applicable_licenses = ["//:license"],
+    default_visibility = ["//visibility:public"],
 )
 
 licenses(["notice"])
@@ -37,8 +37,8 @@ pkg_tar(
         "//licenses/generic:standard_package",
         "//licenses/spdx:standard_package",
         "//rules:standard_package",
-        "//rules_gathering:standard_package",
         "//rules/private:standard_package",
+        "//rules_gathering:standard_package",
         "//sample_reports:standard_package",
         "//tools:standard_package",
     ],

doc_build/BUILD

@@ -21,10 +21,11 @@ How to:
 
 load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
 load("@io_bazel_stardoc//stardoc:stardoc.bzl", "stardoc")
-load("@rules_python//python:defs.bzl", "py_library")
-load("//:version.bzl", "version")
 
-package(default_package_metadata = ["//:license", "//:package_info"])
+package(default_package_metadata = [
+    "//:license",
+    "//:package_info",
+])
 
 filegroup(
     name = "standard_package",
@@ -50,18 +51,18 @@ exports_files(
 # Must put macro wrapped rules after their wrapper
 # buildifier: leave-alone, do not sort
 ORDER = [
-    ("license",         "//rules:license.bzl"),
-    ("_license",        "//rules:license.bzl"),
-    ("license_kind",    "//rules:license_kind.bzl"),
-    ("_license_kind",   "//rules:license_kind.bzl"),
-    ("package_info",    "//rules:package_info.bzl"),
-    ("_package_info",   "//rules:package_info.bzl"),
-    ("LicenseInfo",     "//rules:providers.bzl"),
+    ("license", "//rules:license.bzl"),
+    ("_license", "//rules:license.bzl"),
+    ("license_kind", "//rules:license_kind.bzl"),
+    ("_license_kind", "//rules:license_kind.bzl"),
+    ("package_info", "//rules:package_info.bzl"),
+    ("_package_info", "//rules:package_info.bzl"),
+    ("LicenseInfo", "//rules:providers.bzl"),
     ("LicenseKindInfo", "//rules:providers.bzl"),
-    ("PackageInfo",     "//rules:providers.bzl"),
-    ("gather_metadata_info",           "//rules_gathering:gather_metadata.bzl"),
+    ("PackageInfo", "//rules:providers.bzl"),
+    ("gather_metadata_info", "//rules_gathering:gather_metadata.bzl"),
     ("gather_metadata_info_and_write", "//rules_gathering:gather_metadata.bzl"),
-    ("trace",           "//rules_gathering:trace.bzl"),
+    ("trace", "//rules_gathering:trace.bzl"),
 ]
 
 genrule(

docs/CONTRIBUTING.md

@@ -31,3 +31,9 @@ implementation.
 
 This project follows
 [Google's Open Source Community Guidelines](https://opensource.google/conduct/).
+
+## Formatting and linting
+
+We recommend that you install [pre-commit](https://pre-commit.com) so that your code is automatically
+formatted when you `git commit`.
+We may enforce that code is formatted and/or lint-free in our CI at some point.

examples/manifest/BUILD

@@ -1,6 +1,5 @@
-load(":android_mock.bzl", "android_binary", "android_library")
 load("@rules_license//tools:test_helpers.bzl", "golden_cmd_test")
-
+load(":android_mock.bzl", "android_binary", "android_library")
 
 # These two rules today capture what an android_binary would look like.
 # This rule represents the Android specific code that displays licenses
@@ -13,7 +12,7 @@ android_library(
         "license_display.sh",
     ],
     data = [
-      "@rules_license//distro:distro",
+        "@rules_license//distro",
     ],
 )
 
@@ -25,17 +24,17 @@ android_library(
 android_binary(
     name = "main",
     srcs = ["main.sh"],
-    deps = [
-    ],
     data = [
         ":licenses",
     ],
+    deps = [
+    ],
 )
 
 golden_cmd_test(
     name = "main_test",
     srcs = [],
     cmd = "$(location :main)",
-    tools = [":main"],
     golden = "main_golden.txt",
+    tools = [":main"],
 )

examples/manifest/android_mock.bzl

@@ -1,10 +1,10 @@
-load("manifest.bzl", "manifest")
-
 """This is a proof of concept to show how to modify a macro definition to
 create a sub-graph allowing for build time injection of license information. We
 use Android-inspired rule names since these are a likely candidate for this
 sort of injection."""
 
+load("manifest.bzl", "manifest")
+
 def android_library(name, **kwargs):
     # This is an approximation for demo purposes.
 
@@ -21,6 +21,7 @@ def android_library(name, **kwargs):
         **kwargs
     )
 
+# buildifier: disable=function-docstring
 def android_binary(name, **kwargs):
     # Same observation about not being sloppy with mapping deps, but I think the only important attribute
     # in android_binary is deps, but need to double-check.

examples/manifest/manifest.bzl

@@ -50,10 +50,10 @@ def get_licenses_mapping(deps, warn = False):
         if type(lic.license_text) == "File":
             mappings[lic.license_text] = lic.package_name
         elif warn:
+            # buildifier: disable=print
             print("Legacy license %s not included, rule needs updating" % lic.license_text)
     return mappings
 
-
 def _manifest_impl(ctx):
     # Gather all licenses and make it available as deps for downstream rules
     # Additionally write the list of license filenames to a file that can
@@ -86,4 +86,3 @@ def manifest(name, deps, out = None, **kwargs):
     if not out:
         out = name + ".manifest"
     _manifest(name = name, deps = deps, out = out, **kwargs)
-

examples/policy_checker/BUILD

@@ -3,7 +3,10 @@
 load("@rules_license//examples/policy_checker:license_policy.bzl", "license_policy")
 load("@rules_license//examples/policy_checker:license_policy_check.bzl", "license_policy_check")
 
-package(default_package_metadata = ["//:license", "//:package_info"])
+package(default_package_metadata = [
+    "//:license",
+    "//:package_info",
+])
 
 # license_policy rules generally appear in a central location per workspace. That
 # should be access controlled by the policy team.
@@ -50,7 +53,6 @@ license_policy_check(
     targets = ["//examples/src:my_server"],
 )
 
-
 # This is marked manual, so bazel test ... does not fail. Try it yourself with
 #   bazel build :check_violating_server
 license_policy_check(

examples/policy_checker/license_policy.bzl

@@ -22,7 +22,7 @@ application type (e.g. production_server, mobile_application, ...)
 
 load(
     "@rules_license//examples/policy_checker:license_policy_provider.bzl",
-    "LicensePolicyInfo"
+    "LicensePolicyInfo",
 )
 
 def _license_policy_impl(ctx):

examples/src/BUILD

@@ -18,7 +18,10 @@ load("@rules_license//rules:compliance.bzl", "check_license")
 load("@rules_license//sample_reports:licenses_used.bzl", "licenses_used")
 
 package(
-    default_package_metadata = ["//:license", "//:package_info"],
+    default_package_metadata = [
+        "//:license",
+        "//:package_info",
+    ],
     default_visibility = ["//examples:__subpackages__"],
 )
 

examples/vndor/acme/BUILD

@@ -16,8 +16,8 @@
 load("@rules_license//rules:license.bzl", "license")
 
 package(
-   default_applicable_licenses = [":license"],
-   default_visibility = ["//examples:__subpackages__"],
+    default_applicable_licenses = [":license"],
+    default_visibility = ["//examples:__subpackages__"],
 )
 
 # The default license for an entire package is typically named "license".

examples/vndor/constant_gen/BUILD

@@ -72,8 +72,8 @@ py_test(
     name = "verify_licenses_test",
     srcs = ["verify_licenses_test.py"],
     data = [
-        ":generator_licenses.json",
         ":generated_code_licenses.json",
+        ":generator_licenses.json",
     ],
     python_version = "PY3",
     deps = [

rules/check_licenses_shim.bzl

@@ -14,7 +14,7 @@
 """This module provides a custom Starlark rule used to create wrappers for targets that
 can have blaze build --check_licenses executed against them."""
 
-def _shim_rule_impl(ctx):
+def _shim_rule_impl(_):
     # This rule doesn't need to return anything. It only exists to propagate the dependency supplied
     # by the label_flag
     return []

rules/compliance.bzl

@@ -16,7 +16,6 @@
 load(
     "@rules_license//rules:gather_licenses_info.bzl",
     "gather_licenses_info",
-    "gather_licenses_info_and_write",
     "write_licenses_info",
 )
 load(
@@ -157,6 +156,7 @@ def get_licenses_mapping(deps, warn = False):
         if type(lic.license_text) == "File":
             mappings[lic.license_text] = lic.package_name
         elif warn:
+            # buildifier: disable=print
             print("Legacy license %s not included, rule needs updating" % lic.license_text)
 
     return mappings

rules/gather_licenses_info.bzl

@@ -30,9 +30,9 @@ def _strip_null_repo(label):
     The is to make str(label) compatible between bazel 5.x and 6.x
     """
     s = str(label)
-    if s.startswith('@//'):
+    if s.startswith("@//"):
         return s[1:]
-    elif s.startswith('@@//'):
+    elif s.startswith("@@//"):
         return s[2:]
     return s
 
@@ -150,7 +150,7 @@ def write_licenses_info(ctx, deps, json_out):
     licenses_files = []
     for dep in deps:
         if TransitiveLicensesInfo in dep:
-            transitive_licenses_info = dep[TransitiveLicensesInfo]            
+            transitive_licenses_info = dep[TransitiveLicensesInfo]
             lic_info, _ = licenses_info_to_json(transitive_licenses_info)
             licenses_json.extend(lic_info)
             for info in transitive_licenses_info.licenses.to_list():
@@ -253,6 +253,7 @@ def licenses_info_to_json(licenses_info):
                 label = _strip_null_repo(license.label),
                 used_by = ",\n          ".join(sorted(['"%s"' % x for x in used_by[str(license.label)]])),
             ))
+
             # Additionally return all File references so that other rules invoking
             # this method can load license text file contents from external repos
             # using runfiles

rules/gather_metadata.bzl

@@ -15,6 +15,7 @@
 
 To be deleted before version 0.1.0
 """
+
 load(
     "@rules_license//rules_gathering:gather_metadata.bzl",
     _gather_metadata_info = "gather_metadata_info",

rules/license.bzl

@@ -15,14 +15,14 @@
 
 """
 
-load(
-    "@rules_license//rules:providers.bzl",
-    "LicenseKindInfo",
-)
 load(
     "@rules_license//rules:license_impl.bzl",
     "license_rule_impl",
 )
+load(
+    "@rules_license//rules:providers.bzl",
+    "LicenseKindInfo",
+)
 
 # Enable this if your organization requires the license text to be a file
 # checked into source control instead of, possibly, another rule.
@@ -67,7 +67,7 @@ _license = rule(
             doc = "A human readable version string identifying this package." +
                   " This may be used to produce an index of OSS packages used" +
                   " by an applicatation.  It should be a value that" +
-                  " increases over time, rather than a commit hash."
+                  " increases over time, rather than a commit hash.",
         ),
     },
 )