debugging - Trace Python imports

47
votes

My Python library just changed it's main module name from foo.bar to foobar. For backward compat, foo.bar still exists, but importing it raises a few warnings. Now, it seems some example program still imports from the old module, but not directly.

I'd like to find the erroneous import statement. Is there any tool that allows me to trace imports and find the culprit without wading through all of the code?

2
pythondebuggingimporttrace

2 Answers

73
votes

Start the python interpreter with -v:

$ python -v -m /usr/lib/python2.6/timeit.py
# installing zipimport hook
import zipimport # builtin
# installed zipimport hook
# /usr/lib/python2.6/site.pyc matches /usr/lib/python2.6/site.py
import site # precompiled from /usr/lib/python2.6/site.pyc
# /usr/lib/python2.6/os.pyc matches /usr/lib/python2.6/os.py
import os # precompiled from /usr/lib/python2.6/os.pyc
import errno # builtin
import posix # builtin
# /usr/lib/python2.6/posixpath.pyc matches /usr/lib/python2.6/posixpath.py
import posixpath # precompiled from /usr/lib/python2.6/posixpath.pyc
# /usr/lib/python2.6/stat.pyc matches /usr/lib/python2.6/stat.py
import stat # precompiled from /usr/lib/python2.6/stat.pyc
# /usr/lib/python2.6/genericpath.pyc matches /usr/lib/python2.6/genericpath.py
import genericpath # precompiled from /usr/lib/python2.6/genericpath.pyc
# /usr/lib/python2.6/warnings.pyc matches /usr/lib/python2.6/warnings.py
import warnings # precompiled from /usr/lib/python2.6/warnings.pyc
# /usr/lib/python2.6/linecache.pyc matches /usr/lib/python2.6/linecache.py
import linecache # precompiled from /usr/lib/python2.6/linecache.pyc
# /usr/lib/python2.6/types.pyc matches /usr/lib/python2.6/types.py
import types # precompiled from /usr/lib/python2.6/types.pyc
# /usr/lib/python2.6/UserDict.pyc matches /usr/lib/python2.6/UserDict.py
...

Then just grep for your old module.

8
votes

edit foo.bar module, add following code:

import pdb
pdb.set_trace()

when foo.bar be imported, program will stop at pdb.set_trace() in pdb mode, where you can debug your code. For example, you can use "w" command to print the full calling stack.