String index out of bounds: 3

[runeflobakk]

I think the latest version of equalsverifier introduced a bug in AnnotationCacheBuilder, more specifically line 106. The code assumes that methods which starts with "get" will always have more characters, and will throw a StringIndexOutOfBoundsException on methods simply named get(..)

What steps will reproduce the problem?

Basic EqualsVerifier-test on any class with a method named get.

What is the code that triggers this problem?

Given this class:

public final class MyValue {

    private final long value;

    public MyValue(long value) {
        this.value = value;
    }

    public long get() {
        return value;
    }

    @Override
    public boolean equals(Object o) {
        return o instanceof MyValue && ((MyValue) o).value == this.value;
    }

    @Override
    public int hashCode() {
        return Long.hashCode(value);
    }
}

And this JUnit-test:

import nl.jqno.equalsverifier.EqualsVerifier;
import org.junit.Test;

public class MyValueTest {
    @Test
    public void correctEqualsAndHashCode() {
        EqualsVerifier.forClass(MyValue.class).verify();
    }
}

The test is green on version 3.0.3, but throws the exception below on version 3.1.

What error message or stack trace does EqualsVerifier give?

java.lang.AssertionError: EqualsVerifier found a problem in class MyValue.
-> String index out of range: 3

For more information, go to: http://www.jqno.nl/equalsverifier/errormessages
	at nl.jqno.equalsverifier.EqualsVerifierApi.verify(EqualsVerifierApi.java:308)
	at MyValueTest.correctEqualsAndHashCode(MyValueTest.java:8)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:89)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)
Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: 3
	at java.lang.String.charAt(String.java:658)
	at nl.jqno.equalsverifier.internal.reflection.annotations.AnnotationCacheBuilder.lambda$visitFields$13(AnnotationCacheBuilder.java:106)
	at java.lang.Iterable.forEach(Iterable.java:75)
	at nl.jqno.equalsverifier.internal.reflection.annotations.AnnotationCacheBuilder.visitFields(AnnotationCacheBuilder.java:104)
	at nl.jqno.equalsverifier.internal.reflection.annotations.AnnotationCacheBuilder.visitType(AnnotationCacheBuilder.java:47)
	at nl.jqno.equalsverifier.internal.reflection.annotations.AnnotationCacheBuilder.build(AnnotationCacheBuilder.java:35)
	at nl.jqno.equalsverifier.internal.util.Configuration.buildAnnotationCache(Configuration.java:79)
	at nl.jqno.equalsverifier.internal.util.Configuration.build(Configuration.java:67)
	at nl.jqno.equalsverifier.EqualsVerifierApi.buildConfig(EqualsVerifierApi.java:354)
	at nl.jqno.equalsverifier.EqualsVerifierApi.performVerification(EqualsVerifierApi.java:346)
	at nl.jqno.equalsverifier.EqualsVerifierApi.verify(EqualsVerifierApi.java:302)
	... 24 more

What did you expect?

Green test.

Which version of EqualsVerifier are you using?

Version 3.1.

[jqno]

Thanks for reporting this, it's indeed a bug introduced in version 3.1 at the place you mention.
I've just released version 3.1.1 with a fix!

[runeflobakk]

Wow, that was quick! Thank you!

[jqno]

You're welcome :)