Message9680

In running the Sphinx test suite, I have traced it down: it's due to the use PyInstance (old style class), vs new style class in zipfile.ZipFile:

java.lang.Exception: Stack trace
	at java.lang.Thread.dumpStack(Thread.java:1342)
	at org.python.core.PyMethod.toString(PyMethod.java:327)
	at java.util.Formatter$FormatSpecifier.printString(Formatter.java:2838)
	at java.util.Formatter$FormatSpecifier.print(Formatter.java:2718)
	at java.util.Formatter.format(Formatter.java:2488)
	at java.util.Formatter.format(Formatter.java:2423)
	at java.lang.String.format(String.java:2797)
	at org.python.core.Py.writeUnraisable(Py.java:1285)
	at org.python.core.PyInstance.__del__(PyInstance.java:1958)
	at org.python.core.finalization.FinalizeTrigger.runFinalizer(FinalizeTrigger.java:88)
	at org.python.core.finalization.FinalizeTrigger.performFinalization(FinalizeTrigger.java:170)
	at org.python.core.finalization.FinalizeTrigger.finalize(FinalizeTrigger.java:209)
	at java.lang.ref.Finalizer.invokeFinalizeMethod(Native Method)
	at java.lang.ref.Finalizer.runFinalizer(Finalizer.java:101)
	at java.lang.ref.Finalizer.access$100(Finalizer.java:32)
	at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:190)
Exception java.lang.NullPointerException: java.lang.NullPointerException in <bound method ZipFile.__del__ of <zipfile.ZipFile instance at 0x122>> ignored

(A little instrumentation can help - I did this in PyMethod#toString)

The immediate fix is to convert ZipFile to a newstyle class - this is in fact what it is in CPython 2.7. We can review oldstyle classes at some future point to see if this can be fixed as well.