[Python-checkins] cpython (merge 3.4 -> default): Issue #21905: Avoid RuntimeError in pickle.whichmodule() when sys.modules is

[antoine.pitrou]

https://hg.python.org/cpython/rev/d748a3503ad5
changeset:   92811:d748a3503ad5
parent:      92810:be4debd9a82e
parent:      92809:86ba3bdfac15
user:        Antoine Pitrou <solipsis at pitrou.net>
date:        Sat Oct 04 22:17:26 2014 +0200
summary:
  Issue #21905: Avoid RuntimeError in pickle.whichmodule() when sys.modules is mutated while iterating.

Patch by Olivier Grisel.

files:
  Lib/pickle.py |  4 +++-
  Misc/ACKS     |  1 +
  Misc/NEWS     |  3 +++
  3 files changed, 7 insertions(+), 1 deletions(-)


diff --git a/Lib/pickle.py b/Lib/pickle.py
--- a/Lib/pickle.py
+++ b/Lib/pickle.py
@@ -280,7 +280,9 @@
     module_name = getattr(obj, '__module__', None)
     if module_name is not None:
         return module_name
-    for module_name, module in sys.modules.items():
+    # Protect the iteration by using a list copy of sys.modules against dynamic
+    # modules that trigger imports of other modules upon calls to getattr.
+    for module_name, module in list(sys.modules.items()):
         if module_name == '__main__' or module is None:
             continue
         try:
diff --git a/Misc/ACKS b/Misc/ACKS
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -498,6 +498,7 @@
 Grant Griffin
 Andrea Griffini
 Duncan Grisby
+Olivier Grisel
 Fabian Groffen
 Eric Groo
 Dag Gruneau
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -162,6 +162,9 @@
 Library
 -------
 
+- Issue #21905: Avoid RuntimeError in pickle.whichmodule() when sys.modules
+  is mutated while iterating.  Patch by Olivier Grisel.
+
 - Issue #11271: concurrent.futures.Executor.map() now takes a *chunksize*
   argument to allow batching of tasks in child processes and improve
   performance of ProcessPoolExecutor.  Patch by Dan O'Reilly.

-- 
Repository URL: https://hg.python.org/cpython