Function _assert_no_gc_cycles_context

numpy/testing/_private/utils.py:2581–2629

(name=None)

@contextlib.contextmanager
def _assert_no_gc_cycles_context(name=None):
    __tracebackhide__ = True  # Hide traceback for py.test

    # not meaningful to test if there is no refcounting
    if not HAS_REFCOUNT:
        yield
        return

    assert_(gc.isenabled())
    gc.disable()
    gc_debug = gc.get_debug()
    try:
        for i in range(100):
            if gc.collect() == 0:
                break
        else:
            raise RuntimeError(
                "Unable to fully collect garbage - perhaps a __del__ method "
                "is creating more reference cycles?")

        gc.set_debug(gc.DEBUG_SAVEALL)
        yield
        # gc.collect returns the number of unreachable objects in cycles that
        # were found -- we are checking that no cycles were created in the context
        n_objects_in_cycles = gc.collect()
        objects_in_cycles = gc.garbage[:]
    finally:
        del gc.garbage[:]
        gc.set_debug(gc_debug)
        gc.enable()

    if n_objects_in_cycles:
        name_str = f' when calling {name}' if name is not None else ''
        raise AssertionError(
            "Reference cycles were found{}: {} objects were collected, "
            "of which {} are shown below:{}"
            .format(
                name_str,
                n_objects_in_cycles,
                len(objects_in_cycles),
                ''.join(
                    "\n  {} object with id={}:\n    {}".format(
                        type(o).__name__,
                        id(o),
                        pprint.pformat(o).replace('\n', '\n    ')
                    ) for o in objects_in_cycles
                )
            )
        )


def assert_no_gc_cycles(*args, **kwargs):