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Title: Cannot unpickle classes derived from 'Exception'
Type: behavior Stage: resolved
Components: Interpreter Core Versions: Python 3.2, Python 2.7
Status: closed Resolution: fixed
Dependencies: Superseder:
Assigned To: Nosy List: Aman.Shah, Andreas.Hausmann, alexandre.vassalotti, belopolsky, benjamin.peterson, bpb, brett.cannon, ehuss, facundobatista, fmitha, georg.brandl, jafo, jaraco, jarpa, kylev, loewis, lukasz.langa, nnorwitz, pitrou, python-dev, r.david.murray, sbt, tseaver, vstinner, zbysz, zseil
Priority: normal Keywords: patch

Created on 2013-02-25 17:00 by Andreas.Hausmann, last changed 2022-04-11 14:57 by admin. This issue is now closed.

File name Uploaded Description Edit Andreas.Hausmann, 2013-02-25 17:00 r.david.murray, 2013-02-25 17:36
exception_pickling.patch r.david.murray, 2013-02-27 13:54
issue_17296.patch Aman.Shah, 2013-03-11 08:27 review
issue_17296v2.patch Aman.Shah, 2013-03-11 17:34 Version 2 review
Messages (13)
msg182960 - (view) Author: Andreas Hausmann (Andreas.Hausmann) Date: 2013-02-25 17:00
When pickling/unpickling a class that derives from the builtin class Exception, unpickling results in a

TypeError: ('__init__() takes at least 2 arguments (1 given)', <class '__main__.TestException'>, ())

A standard exception like ValueError can be pickled/unpickled without any problem.

This was observed for versions 2.7.3 and 3.2.3. for both pickle and cPickle.

A script (cpickle) that shows that behavior is included.

This is related (but I do not quite understand how) to the closed Issue1692335.
msg182961 - (view) Author: R. David Murray (r.david.murray) * (Python committer) Date: 2013-02-25 17:04
That issue was only fixed in 3.3.  Does your code work in 3.3?
msg182962 - (view) Author: Andreas Hausmann (Andreas.Hausmann) Date: 2013-02-25 17:14
I have not tried in 3.3. I have no running installation of 3.3.

I need a solution for 2.7 for a Zope project that was just ported to 2.7. My test for Python3 was halfheartedly on my standard Python3 installation (3.2) after reading Issue1692335.
msg182963 - (view) Author: R. David Murray (r.david.murray) * (Python committer) Date: 2013-02-25 17:23
The reason I ask is because that issue ends with "reopen if you think this should be backported", so a backport is at least within the real of possibility :)
msg182964 - (view) Author: R. David Murray (r.david.murray) * (Python committer) Date: 2013-02-25 17:36
I modified your script to run under both python2 and python3.  I get the error for 2.5, 2.6, and 2.7.  The script produces the same output (without the EXCEPTION ## EXCEPTION) under 2.4 and 3.3.
msg183037 - (view) Author: Andreas Hausmann (Andreas.Hausmann) Date: 2013-02-26 09:52
That is correct.

Under 2.4 and 3.3 it should show neither the line "EXCEPTION ## EXCEPTION" nor the following line "TypeError: ('__init__() takes at least 2 arguments....."

That means, that in version 2.4 and 3.3 that unpickling problem doesn't exist. In version 2.4 I tested it myself; exactly, there is no problem. In version 3.3 I simply take your word, that the bug is fixed.
msg183038 - (view) Author: Andreas Hausmann (Andreas.Hausmann) Date: 2013-02-26 09:56
A backport to 2.7 would be in the interest of the Zope community (I dare say ;)), at least in ours.

In our project, after having migrated to Zope 2.13/Python2.7 we found this bug and now we are quite worried what else might happen with our huge pickled database.
msg183151 - (view) Author: R. David Murray (r.david.murray) * (Python committer) Date: 2013-02-27 13:54
I don't have the expertise required to do the 2.7 backport.  My naive attempt is attached, but the message attribute is not preserved (test failure).  If someone can fix the patch, I'll commit it.
msg183152 - (view) Author: Roundup Robot (python-dev) (Python triager) Date: 2013-02-27 14:04
New changeset 2c9f7ed28384 by R David Murray in branch '3.2':
#17296: backport fix for issue 1692335, naive exception pickling.
msg183944 - (view) Author: Aman Shah (Aman.Shah) * Date: 2013-03-11 08:27
Fixed the patch for 2.7
msg183955 - (view) Author: Tres Seaver (tseaver) * Date: 2013-03-11 12:48
The latest 2.7 patch does not cause the following tests (from
issue 1692335) to pass:
msg183982 - (view) Author: Aman Shah (Aman.Shah) * Date: 2013-03-11 17:34
I think it works with the other test also now. Have also included the failed test mentioned by Tres in the patch since it wasn't present in the python2.7 test suite.
msg363539 - (view) Author: Brett Cannon (brett.cannon) * (Python committer) Date: 2020-03-06 20:04
As this was fixed in 3.3 that means all actively maintained versions have the fix, and so closing as fixed.
Date User Action Args
2022-04-11 14:57:42adminsetgithub: 61498
2020-03-06 20:04:29brett.cannonsetstatus: open -> closed
resolution: fixed
messages: + msg363539

stage: resolved
2014-02-04 12:11:49taleinatsetnosy: - taleinat
2013-11-11 11:39:25sbtlinkissue15440 superseder
2013-03-11 18:25:01gvanrossumsetnosy: - gvanrossum
2013-03-11 17:34:39Aman.Shahsetfiles: + issue_17296v2.patch

messages: + msg183982
2013-03-11 12:48:47tseaversetmessages: + msg183955
2013-03-11 08:27:55Aman.Shahsetfiles: + issue_17296.patch
nosy: + Aman.Shah
messages: + msg183944

2013-02-27 14:04:39python-devsetmessages: + msg183152
2013-02-27 13:54:09r.david.murraysetfiles: + exception_pickling.patch
keywords: + patch
messages: + msg183151
2013-02-26 09:56:54Andreas.Hausmannsetmessages: + msg183038
2013-02-26 09:52:42Andreas.Hausmannsetmessages: + msg183037
2013-02-25 17:36:21r.david.murraysetfiles: +

messages: + msg182964
2013-02-25 17:23:05r.david.murraysetmessages: + msg182963
2013-02-25 17:14:40Andreas.Hausmannsetmessages: + msg182962
2013-02-25 17:04:34r.david.murraysetnosy: + r.david.murray
messages: + msg182961
2013-02-25 17:00:16Andreas.Hausmanncreate