test/langtools/tools/javap/ClassFileVersionTest.java

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/*
 * @test
 * @bug 8358078
 * @summary javap should not crash due to class file versions
 * @library /tools/lib
 * @modules jdk.jdeps/com.sun.tools.javap
 * @run junit ClassFileVersionTest
 */

import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.MethodSource;
import toolbox.JavapTask;
import toolbox.Task;
import toolbox.ToolBox;

import java.lang.classfile.ClassFile;
import java.lang.constant.ClassDesc;
import java.lang.reflect.AccessFlag;
import java.lang.reflect.ClassFileFormatVersion;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.stream.Stream;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.params.provider.Arguments.of;

public class ClassFileVersionTest {

    final ToolBox toolBox = new ToolBox();

    public static Stream<Arguments> classFiles() {
        int major17 = ClassFileFormatVersion.RELEASE_17.major();
        int preview = Character.MAX_VALUE;
        int majorLatest = ClassFileFormatVersion.latest().major();
        AccessFlag[] noFlags = {};
        return Stream.of(
            of(false, major17, 0, noFlags),
            of(false, major17, preview, noFlags),
            of(false, 0, 0, noFlags),
            of(false, major17, 0, new AccessFlag[]{AccessFlag.PUBLIC}),
            of(false, major17, preview, new AccessFlag[]{AccessFlag.PUBLIC}),
            of(false, majorLatest, preview, new AccessFlag[]{AccessFlag.PUBLIC}),
            of(true, majorLatest, 0, new AccessFlag[]{AccessFlag.BRIDGE}), // misplaced access flag
            of(true, majorLatest, preview, new AccessFlag[]{AccessFlag.BRIDGE}) // misplaced access flag
        );
    }

    private static byte[] createClassFile(int major, int minor, AccessFlag[] classFlags) {
        return ClassFile.of().build(ClassDesc.of("Test"), (builder) -> {
            // manually assemble flag bits to avoid exception in ClassFile api
            int flags = 0;
            for (AccessFlag classFlag : classFlags) {
                flags |= classFlag.mask();
            }
            builder.withVersion(major, minor).withFlags(flags);
        });
    }

    @ParameterizedTest
    @MethodSource("classFiles")
    void test(boolean shouldError, int major, int minor, AccessFlag[] classFlags) throws Throwable {

        Files.write(Path.of("cf.class"), createClassFile(major, minor, classFlags));

        var lines = new JavapTask(toolBox)
            .classes("cf.class")
            .options("-c", "-p", "-v")
            .run(shouldError ? Task.Expect.FAIL : Task.Expect.SUCCESS)
            .writeAll()
            .getOutputLines(Task.OutputKind.DIRECT);

        assertEquals(shouldError, lines.stream().anyMatch(l -> l.startsWith("Error: Access Flags:")), "printed error");
    }
}