Current File : /opt/alt/python33/share/doc/alt-python33-pip/docs//distribute_setuptools.rst
:orphan:
"ImportError: No module named setuptools"
+++++++++++++++++++++++++++++++++++++++++
Although using ``pip install --upgrade setuptools`` to upgrade from distribute
to setuptools works in isolation, it's possible to get "ImportError: No module
named setuptools" when using pip<1.4 to upgrade a package that depends on
setuptools or distribute.
e.g. when running a command like this: `pip install --upgrade pyramid`
Solution
~~~~~~~~
To prevent the problem in *new* environments (that aren't broken yet):
* Option 1:
* *First* run `pip install -U setuptools`,
* *Then* run the command to upgrade your package (e.g. `pip install --upgrade pyramid`)
* Option 2:
* Upgrade pip using :ref:`get-pip <get-pip>`
* *Then* run the command to upgrade your package (e.g. `pip install --upgrade pyramid`)
To fix the problem once it's occurred, you'll need to manually install the new
setuptools, then rerun the upgrade that failed.
1. Download `ez_setup.py` (https://bitbucket.org/pypa/setuptools/downloads/ez_setup.py)
2. Run `python ez_setup.py`
3. Then rerun your upgrade (e.g. `pip install --upgrade pyramid`)
Cause
~~~~~
distribute-0.7.3 is just an empty wrapper that only serves to require the new
setuptools (setuptools>=0.7) so that it will be installed. (If you don't know
yet, the "new setuptools" is a merge of distribute and setuptools back into one
project).
distribute-0.7.3 does its job well, when the upgrade is done in isolation.
E.g. if you're currently on distribute-0.6.X, then running `pip install -U
setuptools` works fine to upgrade you to setuptools>=0.7.
The problem occurs when:
1. you are currently using an older distribute (i.e. 0.6.X)
2. and you try to use pip to upgrade a package that *depends* on setuptools or
distribute.
As part of the upgrade process, pip builds an install list that ends up
including distribute-0.7.3 and setuptools>=0.7 , but they can end up being
separated by other dependencies in the list, so what can happen is this:
1. pip uninstalls the existing distribute
2. pip installs distribute-0.7.3 (which has no importable setuptools, that pip
*needs* internally to function)
3. pip moves on to install another dependency (before setuptools>=0.7) and is
unable to proceed without the setuptools package
Note that pip v1.4 has fixes to prevent this. distribute-0.7.3 (or
setuptools>=0.7) by themselves cannot prevent this kind of problem.
.. _setuptools: https://pypi.python.org/pypi/setuptools
.. _distribute: https://pypi.python.org/pypi/distribute
