java.lang.IllegalArgumentException: red equals black

[GoogleCodeExporter]

What steps will reproduce the problem?
Here are two classes

public final class AnotherSimpleClass {
    private final transient OutputStream output;
    public AnotherSimpleClass(final OutputStream stream) {
        this.output = stream;
    }
    public boolean equals(final Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        return true;
    }
    public int hashCode() {
        return output != null ? output.hashCode() : 0;
    }
}

and 

public final class SimpleClass {
    private final transient AnotherSimpleClass foo;
    public SimpleClass(final AnotherSimpleClass foo) {
        this.foo = foo;
    }
    public AnotherSimpleClass getFoo() {
        return foo;
    }
    @Override
    public boolean equals(final Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        final SimpleClass that = (SimpleClass) o;
        if (foo != null ? !foo.equals(that.foo) : that.foo != null)
            return false;
        return true;
    }
    @Override
    public int hashCode() {
        return foo != null ? foo.hashCode() : 0;
    }
}

equals and hashcode are generated by IDEA (in production code we use lombok)

Here are tests:
public class SimpleClassTest {
    @Test
    public void testEquals() throws Exception {
        EqualsVerifier.forClass(SimpleClass.class)
            .suppress(Warning.TRANSIENT_FIELDS)
            .verify();
    }
    @Test
    public void testEqualsAnother() throws Exception {
        EqualsVerifier
            .forClass(AnotherSimpleClass.class)
            .suppress(Warning.TRANSIENT_FIELDS)
            .verify();
    }
}

So the fist problem:
AnotherSimpleClass is kinda singleton, so second test failed with
java.lang.AssertionError: Precondition: two objects are equal to each other: 

And as SimpleClass uses AnotherSimpleClass first test failed with:
java.lang.AssertionError: java.lang.IllegalArgumentException: red equals black

I read your post 
http://www.jqno.nl/equalsverifier/2012/11/20/precondition-two-objects-are-equal-
to-each-other/


What version of EqualsVerifier are you using?
1.4.11, 1.5.1

Original issue reported on code.google.com by [email protected] on 7 Dec 2014 at 4:22

[GoogleCodeExporter]

Thanks for posting this.

As for the first problem (AnotherSimpleClass): that's essentially the same 
problem as Issue 46, so I will handle that there.

The second problem (SimpleClass) is a problem in EqualsVerifier. I think it 
should work the way you describe, although I'm not 100% sure yet I can make 
that work. At the very least, the error message should be improved.

Note, btw, that due to the implementation of AnotherSimpleClass's equals 
method, the whole "(foo != null ? !foo.equals(that.foo) : that.foo != null)" is 
basically a no-op if both foos are non-null.

Original comment by [email protected] on 8 Dec 2014 at 1:21

• Changed state: Accepted
• Added labels: ****
• Removed labels: ****

[GoogleCodeExporter]

Both problems are fixed in version 1.6.

Original comment by [email protected] on 17 Jan 2015 at 4:26

• Changed state: Fixed
• Added labels: ****
• Removed labels: ****

[GoogleCodeExporter]

Thank you very much! I'll try new version asap

Original comment by [email protected] on 18 Jan 2015 at 6:19

• Added labels: ****
• Removed labels: ****