StringIndexOutOfBoundsException in `StringUtil.toLowerCaseAndDotted(String) - Fail to accept env variable named 00_PYTHON_2_7

[99sono]

The method io.smallrye.config.common.utils.StringUtil.toLowerCaseAndDotted(String) is causing a java.lang.StringIndexOutOfBoundsException when faced with an input parameter such as 00_PYTHON_2_7. This issue occurs during deployment of an application into WildFly 26.1.3 using the library smallrye-config-common-2.10.0.jar.

Steps to Reproduce:

1. Create a unit test similar to the following:

package deleteMe;

import org.junit.Test;
import io.smallrye.config.common.utils.StringUtil;

public class SmallRyeStringUtilBugTest {

    @Test
    public void toLowerCaseAndDottedTest() {
        String temp01 = StringUtil.toLowerCaseAndDotted("Abc_EFD");

        // This environment variable is accepted:
        // String temp02 = StringUtil.toLowerCaseAndDotted("PYTHON_2_7");

        // However, this environment variable leads to an exception
        String temp02 = StringUtil.toLowerCaseAndDotted("00_PYTHON_2_7");
    }
}

Expected Behavior:
The method should handle input parameters correctly without causing exceptions.

Actual Behavior:
The method throws a StringIndexOutOfBoundsException when processing certain input strings.

Environment:

• WildFly version: 26.1.3
• Library: smallrye-config-common-2.10.0.jar

These were the maven dependencies on my pom.xml

        <dependency>
            <groupId>io.smallrye.config</groupId>
            <artifactId>smallrye-config-core</artifactId>
            <version>2.10.0</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>io.smallrye.config</groupId>
            <artifactId>smallrye-config-common</artifactId>
            <version>2.10.0</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>io.smallrye.config</groupId>
            <artifactId>smallrye-config</artifactId>
            <version>2.10.0</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.jboss.msc</groupId>
            <artifactId>jboss-msc</artifactId>
            <version>1.4.13.Final</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.wildfly</groupId>
            <artifactId>wildfly-microprofile-config-smallrye</artifactId>
            <version>26.1.3.Final</version>
            <scope>test</scope>
        </dependency>

Here is the stack trace from wildfly:

Thread [MSC service thread 1-8] (Suspended (exception java.lang.StringIndexOutOfBoundsException))	
	owns: java.util.concurrent.ConcurrentHashMap<K,V>  (id=640)	
	owns: org.jboss.as.server.deployment.DeploymentUnitPhaseService<T>  (id=641)	
	java.lang.AbstractStringBuilder.checkRangeSIOOBE(int, int, int) line: 1724	
	java.lang.StringBuilder(java.lang.AbstractStringBuilder).replace(int, int, java.lang.String) line: 946	
	java.lang.StringBuilder.replace(int, int, java.lang.String) line: 302	
	io.smallrye.config.common.utils.StringUtil.toLowerCaseAndDotted(java.lang.String) line: 118	
	io.smallrye.config.SmallRyeConfig$ConfigSources.generateDottedProperties(java.util.List<org.eclipse.microprofile.config.spi.ConfigSource>, io.smallrye.config.SmallRyeConfigSourceInterceptorContext) line: 733	
	io.smallrye.config.SmallRyeConfig$ConfigSources.<init>(io.smallrye.config.SmallRyeConfigBuilder) line: 559	
	io.smallrye.config.SmallRyeConfig.<init>(io.smallrye.config.SmallRyeConfigBuilder, io.smallrye.config.ConfigMappings) line: 68	
	org.wildfly.extension.microprofile.config.smallrye.MicroProfileConfigSubsystemAdd$1$1(io.smallrye.config.SmallRyeConfigBuilder).build() line: 449	
	io.smallrye.config.SmallRyeConfigFactory$Default.getConfigFor(io.smallrye.config.SmallRyeConfigProviderResolver, java.lang.ClassLoader) line: 59	
	org.wildfly.extension.microprofile.config.smallrye.MicroProfileConfigSubsystemAdd$1(io.smallrye.config.SmallRyeConfigProviderResolver).getConfig(java.lang.ClassLoader) line: 76	
	org.wildfly.extension.microprofile.config.smallrye.deployment.SubsystemDeploymentProcessor.deploy(org.jboss.as.server.deployment.DeploymentPhaseContext) line: 48	
	org.jboss.as.server.deployment.DeploymentUnitPhaseService<T>.start(org.jboss.msc.service.StartContext) line: 182	
	org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(org.jboss.msc.Service, org.jboss.msc.service.StartContext) line: 1739	
	org.jboss.msc.service.ServiceControllerImpl$StartTask.execute() line: 1701	
	org.jboss.msc.service.ServiceControllerImpl$StartTask(org.jboss.msc.service.ServiceControllerImpl$ControllerTask).run() line: 1559	
	org.jboss.threads.ContextClassLoaderSavingRunnable.run() line: 35	
	org.jboss.threads.EnhancedQueueExecutor.safeRun(java.lang.Runnable) line: 1990	
	org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(java.lang.Runnable) line: 1486	
	org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run() line: 1377	
	org.jboss.msc.service.ServiceContainerImpl$ServiceThread(java.lang.Thread).run() line: 829	

For the unit test exception we have:

java.lang.StringIndexOutOfBoundsException: start -1, end 0, length 2
	at java.base/java.lang.AbstractStringBuilder.checkRangeSIOOBE(AbstractStringBuilder.java:1724)
	at java.base/java.lang.AbstractStringBuilder.replace(AbstractStringBuilder.java:946)
	at java.base/java.lang.StringBuilder.replace(StringBuilder.java:302)
	at io.smallrye.config.common.utils.StringUtil.toLowerCaseAndDotted(StringUtil.java:118)
	at deleteMe.SmallRyeStringUtilBugTest.toLowerCaseAndDottedTest(SmallRyeStringUtilBugTest.java:17)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
	at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)
	at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
	at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
	at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:93)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:40)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:529)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:756)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:452)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:210)

Thanks.

[radcortez]

This was fixed in #1000, available in the latest Wildfly distribution.

I don't think there are going to be updates to WildFly 26.1.3. @xstefank what do you think?

[xstefank]

We could probably backport it of there would be 26.1.4 but that's unlikely.

[radcortez]

@99sono are you able to update Wildfly?

[99sono]

Ah, super. Thanks for that information. Then please feel free to close the defect. No, we cannot simply update WildFly whenever we want. We have specific update windows throughout the year to keep up with the latest and most stable runtime technology. However, it's good to know that this update is available.

In any case, this issue is more of a major annoyance and time-consuming for developers who are surprised by it and encounter difficulties deploying applications that others can deploy. Once you're aware of it, you can easily adapt your development environment to work around the problem. So, it's not critical at all once you have that knowledge.

[radcortez]

Thank you! Sorry for the inconvenience.