Strange internal traceback

[schwehr]

With IPython 0.13 on Python 2.7.3 (default, Apr 15 2012, 16:15:00) from Mac OSX 10.7 (64bit) via fink:

The code in this pastebin causes the following strange traceback when run:

http://pastebin.com/wrFn1zMT

ERROR: Internal Python error in the inspect module.
Below is the traceback from this internal error.
Traceback (most recent call last):
  File "/sw/lib/python2.7/site-packages/IPython/core/ultratb.py", line 756, in structured_traceback
    records = _fixed_getinnerframes(etb, context, tb_offset)
  File "/sw/lib/python2.7/site-packages/IPython/core/ultratb.py", line 242, in _fixed_getinnerframes
    records  = fix_frame_records_filenames(inspect.getinnerframes(etb, context))
  File "/sw/lib/python2.7/inspect.py", line 1043, in getinnerframes
    framelist.append((tb.tb_frame,) + getframeinfo(tb, context))
  File "/sw/lib/python2.7/inspect.py", line 1007, in getframeinfo
    lines, lnum = findsource(frame)
  File "/sw/lib/python2.7/inspect.py", line 580, in findsource
    if pat.match(lines[lnum]): break
IndexError: list index out of range

Unfortunately, your original traceback can not be constructed.

[fperez]

Mmh, that's really odd. It works just fine for me here, on a Linux 64b build of python 2.7.3:

In [6]: run /home/fperez/f.py
version: ['0.8.0']
0 pandas-0.8.0.tar.gz
match: .tar.gz pandas-0.8.0.tar.gz
1 pandas-0.8.0.win-amd64-py2.6.exe
2 pandas-0.8.0.win-amd64-py2.7.exe
3 pandas-0.8.0.win-amd64-py3.1.exe
4 pandas-0.8.0.win-amd64-py3.2.exe
5 pandas-0.8.0.win32-py2.5.exe
6 pandas-0.8.0.win32-py2.6.exe
7 pandas-0.8.0.win32-py2.7.exe
8 pandas-0.8.0.win32-py3.1.exe
9 pandas-0.8.0.win32-py3.2.exe
10 pandas-0.8.0.zip
match: .zip pandas-0.8.0.zip
possible_url {'.tar.gz': 0, '.zip': 10}
---------------------------------------------------------------------------
AssertionError                            Traceback (most recent call last)
/home/fperez/usr/lib/python2.7/site-packages/IPython/utils/py3compat.pyc in execfile(fname, *where)
    177             else:
    178                 filename = fname
--> 179             __builtin__.execfile(filename, *where)

/home/fperez/f.py in <module>()
     38 
     39 if __name__ == '__main__':
---> 40     try_me()
     41 

/home/fperez/f.py in try_me()
     34 
     35 def try_me():
---> 36     package_data = package_url('pandas')
     37     print package_data
     38 

/home/fperez/f.py in package_url(package_name)
     29             entry_num = possible_url[pref]
     30             break
---> 31     assert entry_num
     32 
     33     return urls[entry_num]

AssertionError: 

where f.py is just my save of your pastebin. I know we've had these 'internal inspect errors' occasionally, and I got excited that you might have found a reproducible case so we can finally track things down. But again, it seems this type of error is very, very tricky to replicate. I suspect the inspect module has hidden state that gets messed up, but I haven't done a full audit to see where that could be the case.

But that's what makes these so hard to debug: they only seem to occur during long work sessions, and we've never found a way to replicate one in isolation.

[schwehr]

yeah, I only posted this in hopes that it would correlate with something someone else had seen

[fperez]

I'm going to close it in the sense that this one by itself won't help us fix the problem, but it's still useful to have a record in case we eventually find a way to set the problematic state. So thanks for the report!