InstrumentingClassLoader fails as a parent ClassLoader

[ejona86]

Description

InstrumentingClassLoader does not work properly as a parent class loader, due to missing loadClass(String, boolean) overload which is called by ClassLoader.loadClass(String, boolean). Instead of overriding loadClass(String), InstrumentingClassLoader should override loadClass(String, boolean).

This can produce very weird behavior since multiple class definitions for the same class will exist, including ServiceLoader throwing java.util.ServiceConfigurationError "Provider X not a subtype" since the extending class and its ancestors were loaded from the normal class loader but the class doing the call is loaded from InstrumentingClassLoader

Steps to Reproduce

These two lines return different classes, but they shouldn't:

Class<?> class1 = Class.forName("some.class", false,
    this.getClass().getClassLoader());
Class<?> class2 = Class.forName("some.class", false,
    new ClassLoader(this.getClass().getClassLoader()){});
System.out.println(class1 == class2);

Robolectric & Android Version

3.1 SNAPSHOT, commit 78ef7fa

[ejona86]

My previous test didn't quite precise enough, because it depended a lot on the environment and order of operations happening outside of the code snippet. This unit test should work:

class OnlyUsedByChildClassLoaderTest {}

@Test
public void testChildClassLoaderReturnsSameInstanceAsParent() throws Exception {
  // Must not use .class. This class must be loaded from the child first
  String name = getClass().getName() + "$OnlyUsedByChildClassLoaderTest";
  // Note that reversing this line and the next line produces different results
  Class<?> fromChild = Class.forName(name, false,
      new ClassLoader(getClass().getClassLoader()) {});
  Class<?> fromIntrumented = Class.forName(name, false,
      getClass().getClassLoader());
  // Just a sanity test
  assertThat(fromIntrumented).isSameAs(OnlyUsedByChildClassLoaderTest.class);
  // The real verification
  assertThat(fromChild).isSameAs(fromIntrumented);
}

[jongerrish]

I believe this has been fixed.