The assertion failure occurs in _PyObject_GC_TRACK() at:

static void
gen_dealloc(PyGenObject *gen)
{
    PyObject *self = (PyObject *) gen;

    _PyObject_GC_UNTRACK(gen);

    if (gen->gi_weakreflist != NULL)
        PyObject_ClearWeakRefs(self);

    _PyObject_GC_TRACK(self);  // <==== HERE

    ...
}

It's surprising that the generator is still tracked by the GC after _PyObject_GC_UNTRACK().


> Calling this a compile error - as it seems to be compiler dependent.

Do you reproduce the bug if you build Python with GCC?

Which ./configure command did you use? What are the compiler and linker flags?

You can try:

./python -m test.pythoninfo|grep -E 'CFLAGS|CC|OPT|LDFLAGS'