diff --git a/Lib/unittest/case.py b/Lib/unittest/case.py index bedbc670d21..aa00b7accf4 100644 --- a/Lib/unittest/case.py +++ b/Lib/unittest/case.py @@ -9,6 +9,7 @@ import re import warnings import collections import contextlib +import traceback from . import result from .util import (strclass, safe_repr, _count_diff_all_purpose, @@ -178,6 +179,8 @@ class _AssertRaisesContext(_AssertRaisesBaseContext): self.obj_name)) else: self._raiseFailure("{} not raised".format(exc_name)) + else: + traceback.clear_frames(tb) if not issubclass(exc_type, self.expected): # let unexpected exceptions pass through return False diff --git a/Lib/unittest/test/test_assertions.py b/Lib/unittest/test/test_assertions.py index af08d5ad65a..c349a95794f 100644 --- a/Lib/unittest/test/test_assertions.py +++ b/Lib/unittest/test/test_assertions.py @@ -1,5 +1,6 @@ import datetime import warnings +import weakref import unittest from itertools import product @@ -97,6 +98,36 @@ class Test_Assertions(unittest.TestCase): else: self.fail("assertRaises() didn't let exception pass through") + def test_assertRaises_frames_survival(self): + # Issue #9815: assertRaises should avoid keeping local variables + # in a traceback alive. + class A: + pass + wr = None + + class Foo(unittest.TestCase): + + def foo(self): + nonlocal wr + a = A() + wr = weakref.ref(a) + try: + raise IOError + except IOError: + raise ValueError + + def test_functional(self): + self.assertRaises(ValueError, self.foo) + + def test_with(self): + with self.assertRaises(ValueError): + self.foo() + + Foo("test_functional").run() + self.assertIsNone(wr()) + Foo("test_with").run() + self.assertIsNone(wr()) + def testAssertNotRegex(self): self.assertNotRegex('Ala ma kota', r'r+') try: diff --git a/Misc/NEWS b/Misc/NEWS index 856520fb2bc..3975afa4625 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -39,6 +39,9 @@ Core and Builtins Library ------- +- Issue #9815: assertRaises now tries to clear references to local variables + in the exception's traceback. + - Issue #13204: Calling sys.flags.__new__ would crash the interpreter, now it raises a TypeError.