[ python-Bugs-1176893 ] Readline segfault

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Bugs item #1176893, was opened at 2005-04-05 04:50
Message generated for change (Comment added) made by tim_one
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Category: Python Library
Group: Python 2.5
Status: Open
Resolution: None
Priority: 5
Submitted By: Walter Dörwald (doerwalter)
>Assigned to: Mark Hammond (mhammond)
Summary: Readline segfault

Initial Comment:
The latest change to the readline module has broken tab
completion:

./python
Python 2.5a0 (#1, Apr  5 2005, 01:14:33) 
[GCC 3.3.5  (Gentoo Linux 3.3.5-r1, ssp-3.3.2-3,
pie-8.7.7.1)] on linux2
Type "help", "copyright", "credits" or "license" for
more information.
>>> import readline, rlcompleter
[25913 refs]
>>> readline.parse_and_bind("tab: complete")
[25913 refs]
>>> Segmentation fault

[Press tab after the parse_and_bind() call]

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>Comment By: Tim Peters (tim_one)
Date: 2005-04-07 11:15

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Sorry, can't make time for this.  Reassigned to Mark in case 
he can.

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Comment By: Michael Hudson (mwh)
Date: 2005-04-05 06:27

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Or maybe this one line patch is the answer (it certainly
fixes this case).

Tim, can you spare a minute to think about this?  The patch
simply adds a check to PyEval_ReleaseThread that doesn't
call PyThread_release_lock if the GIL hasn't been allocated.

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Comment By: Michael Hudson (mwh)
Date: 2005-04-05 06:18

Message:
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I'm going to go out on a limb and suggest this is a bug in
the PyGilState_ functions.

The problem burrows down to calling
PyThread_release_lock(interpreter_lock) when
interpreter_lock is NULL, i.e. PyEval_InitThreads hasn't
been called. (if you start a thread before running the
crashing code, it doesn't crash, because the GIL has been
allocated).

Not sure what the solution is, or who to bug (time to read
cvs log, I guess).
A silly workaround is to put PyEval_InitThreads in initreadline.

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