javaagent/java 7 and custom javassist not working together: stack shape inconsistent

[johanhaleby]

From gdel...@gmail.com on December 02, 2014 18:23:18

What steps will reproduce the problem? 1. Write an empty test with a before class method
2. add as content of the beforeClass method this:
ClassPool cp = ClassPool.getDefault();
CtClass cc = cp.get("java.lang.String");
ClassFile cf = cc.getClassFile();
List methods = cf.getMethods();
for (MethodInfo m : methods) {
System.out.println(m.getName());
}
3. Add the javaagent to the VM argument : -javaagent:powermock-module-javaagent-1.6.0.jar, in the run classpath, set the javaagent jar first
4. Make sure to set the compliance of the project to 1.7 (using a JRE 7)
4. Launch test with the standard JUnit4 runner What is the expected output? What do you see instead? I expect the test to pass as with Java 6, instead I get:
java.lang.VerifyError: JVMVRFY012 stack shape inconsistent; class=TestPSC, method=beforeClass()V, pc=29
at java.lang.J9VMInternals.prepareClassImpl(Native Method)
at java.lang.J9VMInternals.prepare(J9VMInternals.java:430)
at java.lang.Class.getMethod(Class.java:1061)
at org.junit.internal.builders.SuiteMethodBuilder.hasSuiteMethod(SuiteMethodBuilder.java:18)
at org.junit.internal.builders.SuiteMethodBuilder.runnerForClass(SuiteMethodBuilder.java:10)
at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:26)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.(JUnit4TestReference.java:33)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestClassReference.(JUnit4TestClassReference.java:25)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createTest(JUnit4TestLoader.java:48)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.loadTests(JUnit4TestLoader.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:444)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192) What version of the product are you using? On what operating system? JUnit 4.11, Powermock 1.6.0, javassist 3.18.2-GA Please provide any additional information below. Launching with a compliance 1.6 works perfectly fine, launching with 1.7 fails. I have also tried to add the option -XX:-UseSplitVerifier. And the javaagent jar is first in the classpath.

Any ideas?

Thank you!

Guillaume

The class is:

@Rule
public PowerMockRule rule = new PowerMockRule ();

static { PowerMockAgent .initializeIfNeeded();
}

@BeforeClass
public static void beforeClass() throws NotFoundException, CannotCompileException {
    ClassPool cp = ClassPool.getDefault();
    CtClass cc = cp.get("java.lang.String");
    ClassFile cf = cc.getClassFile();
    List<MethodInfo> methods = cf.getMethods();
    for (MethodInfo m : methods) {
        System.out.println(m.getName());
    }
}

@Test
public void test() throws Exception {
}

Original issue: http://code.google.com/p/powermock/issues/detail?id=529

[johanhaleby]

From gdel...@gmail.com on December 02, 2014 09:28:36

I forgot to say that, to isolate the problem, I made a really dummy class being this:

public class TestA {

public static void main(String[] args) throws NotFoundException {
    ClassPool cp = ClassPool.getDefault();
    CtClass cc = cp.get("java.lang.String");
    ClassFile cf = cc.getClassFile();
    List<MethodInfo> methods = cf.getMethods();
    for (MethodInfo m : methods) {
        System.out.println(m.getName());
    }
}

}

And under Java 7, it runs fine without the powermock agent, as soon as I add the VM argument: -javaagent:powermock-module-javaagent-1.6.0.jar
it fails with the same error. So there is something wrong between javassist and the powermock javaagent under Java 7, or maybe I doing something wrong :)

[johanhaleby]

From gdel...@gmail.com on December 18, 2014 04:34:55

Output with a JRE 7 SUN 32 bits is the following:

Exception in thread "main" java.lang.VerifyError: Expecting a stackmap frame at branch target 57
Exception Details:
  Location:
    TestA.main([Ljava/lang/String;)V @31: goto
  Reason:
    Expected stackmap frame at this location.
  Bytecode:
    0000000: b800 154c 2b12 17b6 001b 4d2c b600 214e
    0000010: 2db6 0027 3a04 1904 b900 2d01 003a 06a7
    0000020: 001a 1906 b900 3301 00c0 0035 3a05 b200
    0000030: 3b19 05b6 003f b600 4519 06b9 0049 0100
    0000040: 9aff e2b2 003b 124b b600 45b1          

    at java.lang.Class.getDeclaredMethods0(Native Method)
    at java.lang.Class.privateGetDeclaredMethods(Unknown Source)
    at java.lang.Class.getMethod0(Unknown Source)
    at java.lang.Class.getMethod(Unknown Source)
    at sun.launcher.LauncherHelper.getMainMethod(Unknown Source)
    at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)

[johanhaleby]

From gdel...@gmail.com on December 19, 2014 02:32:51

The problem seems to come from the transformer class org.powermock.modules.agent.DefinalizingClassTransformer which rewrites the bytecode of class when loading. I guess there is something wrong in the rewriting from the ClassWriter or PowerMockClassVisitor classes but for now I don't have enough knowledge nor time to tell where is the problem.

[johanhaleby]

From gdel...@gmail.com on December 19, 2014 02:36:11

Also for the moment I found a workaround/fix (don't know if there is a way to fix the agent to make it work without the flag). I explain here ( http://www.notonlyanecmplace.com/java-7-enforces-bytecode-verification/ ) but basically you can just disable the bytecode verification on IBM JRE or fallback to the old one on SUN JRE. I'll try to see if there is a better fix so it passes the verification, but help from the author would be nice because it is a bit too much for me now :)

[Vampire]

Probably fixed by #1043