gedit 'External Tools' plugin hashlib weirdness

[Joel Hedlund]

I'm having a weird problem with the 'External Tools' plugin for gedit,
that seems to get weirder the more I dig into it. When I start gedit
by clicking a launcher (from the Ubuntu menu, panel or desktop)
everything is dandy and the 'External Tools' plugin works as expected.
When gedit is launched from the terminal, the 'External Tools' plugin
is greyed out in the plugin list and I get this traceback on stderr:

$ gedit
Traceback (most recent call last):
  File "/usr/lib/gedit-2/plugins/externaltools/__init__.py", line 24,
in <module>
    from manager import Manager
  File "/usr/lib/gedit-2/plugins/externaltools/manager.py", line 27,
in <module>
    import hashlib
  File "/usr/lib/python2.6/hashlib.py", line 136, in <module>
    md5 = __get_builtin_constructor('md5')
  File "/usr/lib/python2.6/hashlib.py", line 63, in
__get_builtin_constructor
    import _md5
ImportError: No module named _md5

** (gedit:8714): WARNING **: Error loading plugin 'External Tools'

The same thing happens if I try to activate the plugin from a gedit
launched from the terminal (if it's already been deactivated from a
gedit launched from the menu).

My analysis is that gedit tries to import the externaltools package,
which imports hashlib, which tries to import _hashlib but fails and
falls back to _md5 which also fails, which apparently /should not
happen/, or so google tells me. One of _hashlib and _md5 should always
exist.

However, importing _hashlib in a python interpreter works just fine,
i.e:

$ python -c 'import _hashlib'

returns nothing. What also puzzles me is that I don't seem to have
_hashlib* anywhere on my system (am I supposed to?) and getting the
__file__ attribute off the module doesn't work, and help(_hashlib)
says FILE is (built-in).

>>> import _hashlib
>>> _hashlib.__file__
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'module' object has no attribute '__file__'

Google drops vague hints that there may be a a virtualenv that one
might have to rebuild, but in that case I have no idea where to
begin.

I've tried reinstalling the ubuntu packages gedit, gedit-common and
gedit-plugins, but to no avail. And the machine runs a fully updated
ubuntu karmic koala (10.4) that has survived numerous dist-upgrades,
if that's of any use to anybody.

I'd appreciate any input on this, even if it's just new bushes to
whack for scaring the problem out into the light.

Cheers!
/Joel