import re import types import unittest import weakref from test import support class ClearTest(unittest.TestCase): """ Tests for frame.clear(). """ def inner(self, x=5, **kwargs): 1/0 def outer(self, **kwargs): try: self.inner(**kwargs) except ZeroDivisionError as e: exc = e return exc def clear_traceback_frames(self, tb): """ Clear all frames in a traceback. """ while tb is not None: tb.tb_frame.clear() tb = tb.tb_next def test_clear_locals(self): class C: pass c = C() wr = weakref.ref(c) exc = self.outer(c=c) del c support.gc_collect() # A reference to c is held through the frames self.assertIsNot(None, wr()) self.clear_traceback_frames(exc.__traceback__) support.gc_collect() # The reference was released by .clear() self.assertIs(None, wr()) def test_clear_generator(self): endly = False def g(): nonlocal endly try: yield self.inner() finally: endly = True gen = g() next(gen) self.assertFalse(endly) # Clearing the frame closes the generator gen.gi_frame.clear() self.assertTrue(endly) def test_clear_executing(self): # Attempting to clear an executing frame is forbidden. try: 1/0 except ZeroDivisionError as e: f = e.__traceback__.tb_frame with self.assertRaises(RuntimeError): f.clear() with self.assertRaises(RuntimeError): f.f_back.clear() def test_clear_executing_generator(self): # Attempting to clear an executing generator frame is forbidden. endly = False def g(): nonlocal endly try: 1/0 except ZeroDivisionError as e: f = e.__traceback__.tb_frame with self.assertRaises(RuntimeError): f.clear() with self.assertRaises(RuntimeError): f.f_back.clear() yield f finally: endly = True gen = g() f = next(gen) self.assertFalse(endly) # Clearing the frame closes the generator f.clear() self.assertTrue(endly) @support.cpython_only def test_clear_refcycles(self): # .clear() doesn't leave any refcycle behind with support.disable_gc(): class C: pass c = C() wr = weakref.ref(c) exc = self.outer(c=c) del c self.assertIsNot(None, wr()) self.clear_traceback_frames(exc.__traceback__) self.assertIs(None, wr()) class FrameAttrsTest(unittest.TestCase): def make_frames(self): def outer(): x = 5 y = 6 def inner(): z = x + 2 1/0 t = 9 return inner() try: outer() except ZeroDivisionError as e: tb = e.__traceback__ frames = [] while tb: frames.append(tb.tb_frame) tb = tb.tb_next return frames def test_locals(self): f, outer, inner = self.make_frames() outer_locals = outer.f_locals self.assertIsInstance(outer_locals.pop('inner'), types.FunctionType) self.assertEqual(outer_locals, {'x': 5, 'y': 6}) inner_locals = inner.f_locals self.assertEqual(inner_locals, {'x': 5, 'z': 7}) def test_clear_locals(self): # Test f_locals after clear() (issue #21897) f, outer, inner = self.make_frames() outer.clear() inner.clear() self.assertEqual(outer.f_locals, {}) self.assertEqual(inner.f_locals, {}) def test_locals_clear_locals(self): # Test f_locals before and after clear() (to exercise caching) f, outer, inner = self.make_frames() outer.f_locals inner.f_locals outer.clear() inner.clear() self.assertEqual(outer.f_locals, {}) self.assertEqual(inner.f_locals, {}) def test_f_lineno_del_segfault(self): f, _, _ = self.make_frames() with self.assertRaises(AttributeError): del f.f_lineno class ReprTest(unittest.TestCase): """ Tests for repr(frame). """ def test_repr(self): def outer(): x = 5 y = 6 def inner(): z = x + 2 1/0 t = 9 return inner() offset = outer.__code__.co_firstlineno try: outer() except ZeroDivisionError as e: tb = e.__traceback__ frames = [] while tb: frames.append(tb.tb_frame) tb = tb.tb_next else: self.fail("should have raised") f_this, f_outer, f_inner = frames file_repr = re.escape(repr(__file__)) self.assertRegex(repr(f_this), r"^$" % (file_repr, offset + 23)) self.assertRegex(repr(f_outer), r"^$" % (file_repr, offset + 7)) self.assertRegex(repr(f_inner), r"^$" % (file_repr, offset + 5)) if __name__ == "__main__": unittest.main()