From 1a3bc5546aa27f01426ad76618a9b2c3b698ae68 Mon Sep 17 00:00:00 2001 From: Serhiy Storchaka Date: Tue, 4 Jul 2017 07:55:45 +0300 Subject: [PATCH] [3.5] bpo-30441: Fix bug when modifying os.environ while iterating over it (GH-2409). (#2557) (cherry picked from commit 8a8d28501fc8ce25926d168f1c657656c809fd4c) --- Lib/os.py | 4 +++- Lib/test/test_os.py | 24 +++++++++++++++++++ Misc/ACKS | 1 + .../2017-06-29-14-25-14.bpo-30441.3Wh9kc.rst | 1 + 4 files changed, 29 insertions(+), 1 deletion(-) create mode 100644 Misc/NEWS.d/next/Library/2017-06-29-14-25-14.bpo-30441.3Wh9kc.rst diff --git a/Lib/os.py b/Lib/os.py index 011285e74b..b1add54cf2 100644 --- a/Lib/os.py +++ b/Lib/os.py @@ -741,7 +741,9 @@ class _Environ(MutableMapping): raise KeyError(key) from None def __iter__(self): - for key in self._data: + # list() from dict object is an atomic operation + keys = list(self._data) + for key in keys: yield self.decodekey(key) def __len__(self): diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py index e9c850793a..6dc05eb7fd 100644 --- a/Lib/test/test_os.py +++ b/Lib/test/test_os.py @@ -809,6 +809,30 @@ class EnvironTests(mapping_tests.BasicTestMappingProtocol): self.assertIs(cm.exception.args[0], missing) self.assertTrue(cm.exception.__suppress_context__) + def _test_environ_iteration(self, collection): + iterator = iter(collection) + new_key = "__new_key__" + + next(iterator) # start iteration over os.environ.items + + # add a new key in os.environ mapping + os.environ[new_key] = "test_environ_iteration" + + try: + next(iterator) # force iteration over modified mapping + self.assertEqual(os.environ[new_key], "test_environ_iteration") + finally: + del os.environ[new_key] + + def test_iter_error_when_changing_os_environ(self): + self._test_environ_iteration(os.environ) + + def test_iter_error_when_changing_os_environ_items(self): + self._test_environ_iteration(os.environ.items()) + + def test_iter_error_when_changing_os_environ_values(self): + self._test_environ_iteration(os.environ.values()) + class WalkTests(unittest.TestCase): """Tests for os.walk().""" diff --git a/Misc/ACKS b/Misc/ACKS index 7f9044ac7c..5440326ac3 100644 --- a/Misc/ACKS +++ b/Misc/ACKS @@ -1056,6 +1056,7 @@ Vilmos Nebehaj Fredrik Nehr Tony Nelson Trent Nelson +Osvaldo Santana Neto Chad Netzer Max Neunhöffer Anthon van der Neut diff --git a/Misc/NEWS.d/next/Library/2017-06-29-14-25-14.bpo-30441.3Wh9kc.rst b/Misc/NEWS.d/next/Library/2017-06-29-14-25-14.bpo-30441.3Wh9kc.rst new file mode 100644 index 0000000000..55dd6136c8 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2017-06-29-14-25-14.bpo-30441.3Wh9kc.rst @@ -0,0 +1 @@ +Fix bug when modifying os.environ while iterating over it -- 2.40.0