Strange bug doesn't occur in Pydb

[Diez B. Roggisch]

kj wrote:

> In <6bb01lF38u72tU1 at mid.uni-berlin.de> "Diez B. Roggisch"
> <deets at nospam.web.de> writes:
> 
>>kj schrieb:
>>> I'm running into a strange seg fault with the module cjson.  The
>>> strange part is that it does not occur when I run the code under
>>> Emacs' Pydb.
>>> 
>>> Here's an example:
>>> 
>>> 
>>> import sys, cjson
>>> 
>>> d1 = {'a': 1, 'b': 2, 'c': 3}
>>> print sys.version
>>> j1 = cjson.encode(d1)
>>> print j1   # should print the string '{"a": 1, "c": 3, "b": 2}'
>>> 
>>> The code above runs fine under Pydb, but segfaults at the call to
>>> cjson.encode when I run it from the command line in a standard
>>> Linux shell interaction.  In the printed version strings are
>>> identical.
>>> 
>>> I figure this must be a bug in cjson.  I'd love to find a workaround
>>> for it, and hope that this strange difference between Pydb and the
>>> shell command line may be a clue to that.
>>> 
>>> Any thoughts?
> 
>>Are you sure you actually run the same interpreter in emacs as you do on
>>the commandline?
> 
> No, I'm not.  All I know is that both Emacs and the commandline
> are running on the same machine, and that the version string that
> the program prints is the same in both conditions.  How can I verify
> that that the same interpreter is running in both cases?

By e.g. 

import sys
print sys.prefix

Additionally, you should compare what

sys.path

contains and if it's the same - otherwise it might be that cjson is picked
up from somewhere else.

If all that's the case, I'd invoke python through gdb and see where the
segfault happens.

BTW: I've been using (and even patching) cjson - without any troubles
whatsoever.

Diez