test/jdk/java/lang/annotation/MalformedAnnotationTest.java

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/*
 * @test
 * @bug 8350704
 * @summary Test behaviors with malformed annotations (in class files)
 * @library /test/lib
 * @run junit MalformedAnnotationTest
 */

import jdk.test.lib.ByteCodeLoader;
import org.junit.jupiter.api.Test;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.classfile.Annotation;
import java.lang.classfile.AnnotationElement;
import java.lang.classfile.AnnotationValue;
import java.lang.classfile.ClassFile;
import java.lang.classfile.attribute.RuntimeVisibleAnnotationsAttribute;
import java.lang.constant.ClassDesc;
import java.lang.reflect.GenericSignatureFormatError;

import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;

class MalformedAnnotationTest {

    /**
     * An annotation that has elements of the Class type.
     * Useful for checking behavior when the string is not a descriptor string.
     */
    @Retention(RetentionPolicy.RUNTIME)
    @interface ClassCarrier {
        Class<?> value();
    }

    /**
     * Ensures bad class descriptors in annotations lead to
     * {@link GenericSignatureFormatError} and the error message contains the
     * malformed descriptor string.
     */
    @Test
    void testMalformedClassValue() throws Exception {
        var badDescString = "Not a_descriptor";
        var bytes = ClassFile.of().build(ClassDesc.of("Test"), clb -> clb
                .with(RuntimeVisibleAnnotationsAttribute.of(
                        Annotation.of(ClassCarrier.class.describeConstable().orElseThrow(),
                                AnnotationElement.of("value", AnnotationValue.ofClass(clb
                                        .constantPool().utf8Entry(badDescString))))
                )));
        var cl = new ByteCodeLoader("Test", bytes, MalformedAnnotationTest.class.getClassLoader()).loadClass("Test");
        var ex = assertThrows(GenericSignatureFormatError.class, () -> cl.getDeclaredAnnotation(ClassCarrier.class));
        assertTrue(ex.getMessage().contains(badDescString), () -> "Uninformative error: " + ex);
    }
}