Incorrect type variable resolution for signatures

[pbull-oracle]

When indexing multiple classes, during class signature parsing/resolution, the wrong bounds can be resolved for a type variable, because the indexer reuses the signature parser and the signature parser reuses resolved type variables between consecutive calls to the index method.

Reproduce with:

package com.example;
public interface WithMethodSignature {
    public <E extends Runnable> E myMethod(E arg);
}

package com.example;
import java.util.Iterator;
public interface WithClassSignature<E extends Exception> extends Iterator<E /*what's the bound?*/ > {
}

package com.example;
import java.io.InputStream;
import org.assertj.core.api.Assertions;
import org.jboss.jandex.ClassInfo;
import org.jboss.jandex.DotName;
import org.jboss.jandex.Index;
import org.jboss.jandex.Indexer;
import org.junit.jupiter.api.Test;
public class JandexTest {
    @Test //passes
    public void classSignatureOnly()
            throws Exception {
        verifyIndex(createIndex(WithClassSignature.class), WithClassSignature.class);
    }
    @Test //passes
    public void classSignatureBeforeMethodSignature()
            throws Exception {
        verifyIndex(createIndex(WithClassSignature.class, WithMethodSignature.class), WithClassSignature.class);
    }
    @Test //fails
    public void classSignatureAfterMethodSignature()
            throws Exception {
        verifyIndex(createIndex(WithMethodSignature.class, WithClassSignature.class), WithClassSignature.class);
    }
    private Index createIndex(Class<?>... types)
            throws Exception {
        Indexer indexer = new Indexer();
        for (Class<?> type : types) { //order matters
            String classNameAsResource = type.getName().replace('.', '/') + ".class";
            try (InputStream fis = type.getClassLoader().getResourceAsStream(classNameAsResource);) {
                indexer.index(fis);
            }
        }
        Index index = indexer.complete();
        return index;
    }
    private void verifyIndex(Index index, Class<?> generic) {
        DotName bound = DotName.createSimple(((Class<?>) generic.getTypeParameters()[0].getBounds()[0]).getName());
        ClassInfo indexedGeneric = index.getClassByName(DotName.createSimple(generic.getName()));
        DotName indexedInterfaceBound = indexedGeneric.interfaceTypes().get(0).asParameterizedType().arguments().get(0).asTypeVariable()
                .bounds().get(0).asClassType().name();
        Assertions.assertThat(indexedInterfaceBound).isEqualTo(bound);
    }
}

[n1hility]

Thanks for the report

[Ladicek]

Fix is a single line of code. The signature parser forgets previously encountered element-level type parameters when parsing a new element, and previously encountered class-level type parameters when parsing a new class. It doesn't forget previously encountered element-level type parameters when parsing a new class, which it should.

[Ladicek]

Done in #202.