From: Andrew M. Kuchling <amk@amk.ca>
Date: Fri, 2 Apr 2010 17:48:23 +0000 (+0000)
Subject: #6647: document that catch_warnings is not thread-safe
X-Git-Tag: v2.7b1~140
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d8862904641efabcded42a8db16f255f171e59e7;p=thirdparty%2FPython%2Fcpython.git

#6647: document that catch_warnings is not thread-safe
---

diff --git a/Doc/library/warnings.rst b/Doc/library/warnings.rst
index e4343e87fad0..91ab0854b57a 100644
--- a/Doc/library/warnings.rst
+++ b/Doc/library/warnings.rst
@@ -381,6 +381,14 @@ Available Context Managers
     protected. This argument exists primarily for testing the :mod:`warnings`
     module itself.
 
+    .. note::
+
+        The :class:`catch_warnings` manager works by replacing and
+        then later restoring the module's
+        :func:`showwarning` function and internal list of filter
+        specifications.  This means the context manager is modifying
+        global state and therefore is not thread-safe.
+
     .. note::
 
         In Python 3.0, the arguments to the constructor for