`pip install -t`不适用于命名空间包

Question

When I install a package with pip install -t some_dir , I can usually then add some_dir to my PYTHONPATH when running python and import the package. Like this:

~/dev/scratch [venv] » pip install -t some_dir pytest
...
Successfully installed py pytest
~/dev/scratch [venv]  » PYTHONPATH=some_dir python
...
>>> import pytest
>>>

However, I recently added the library "stompest" to my dependencies, which is apparently a "namespace package" (not entirely sure what that means). It doesn't seem to work with this same pattern:

~/dev/scratch [venv]  » pip install -t some_dir stompest
...
Successfully installed stompest
~/dev/scratch [venv]  » PYTHONPATH=some_dir python
...
>>> import stompest.config
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named stompest.config

It works fine if I just install stompest normally (into a virtual environment, say):

~/dev/scratch [venv]  » pip install stompest
...
Successfully installed stompest-2.1.6
~/dev/scratch [venv]  » python
...
>>> import stompest.config
>>>

The problem seems to be that pip(?) lays down a .pth file that expects to be in the site-dir (notice f_locals['sitedir'] below):

~/dev/scratch [venv]  » cat some_dir/stompest-2.1.6-py2.7-nspkg.pth
import sys,types,os; p = os.path.join(sys._getframe(1).f_locals['sitedir'], *('stompest',)); ie = os.path.exists(os.path.join(p,'__init__.py')); m = not ie and sys.modules.setdefault('stompest',types.ModuleType('stompest')); mp = (m or []) and m.__dict__.setdefault('__path__',[]); (p not in mp) and mp.append(p)

I tried also setting PYTHONUSERBASE=some_dir , but that didn't seem to make any difference. It seems like a similar issue to this one , which suggests using --egg as a workaround. I can't get --egg to work with -t , though, because I get an error that I am "attempting to install a package to a directory that is not on PYTHONPATH and which Python does not read ".pth" files from." The problem is that I can't add the directory to PYTHONPATH because it seems to be trying to install to a temporary directory:

~/dev/scratch [venv]  » PYTHONPATH=some_dir pip install -t some_dir --egg stompest
Collecting stompest
  Using cached stompest-2.1.6.tar.gz
Installing collected packages: stompest
  Running setup.py install for stompest
    Complete output from command /home/nalderso/dev/scratch/venv/bin/python -c "import setuptools, tokenize;__file__='/tmp/pip-build-Wc3oaO/stompest/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-fZlXM2-record/install-record.txt --compile --install-headers /home/nalderso/dev/scratch/venv/include/site/python2.7/stompest --home=/tmp/tmpHNVOP0:
    running install
    Checking .pth file support in /tmp/tmpHNVOP0/lib/python/
    /home/nalderso/dev/scratch/venv/bin/python -E -c pass
    TEST FAILED: /tmp/tmpHNVOP0/lib/python/ does NOT support .pth files
    error: bad install directory or PYTHONPATH

    You are attempting to install a package to a directory that is not
    on PYTHONPATH and which Python does not read ".pth" files from.  The
    installation directory you specified (via --install-dir, --prefix, or
    the distutils default setting) was:

        /tmp/tmpHNVOP0/lib/python/

    and your PYTHONPATH environment variable currently contains:

        'some_dir'

    Here are some of your options for correcting the problem:

    * You can choose a different installation directory, i.e., one that is
      on PYTHONPATH or supports .pth files

    * You can add the installation directory to the PYTHONPATH environment
      variable.  (It must then also be on PYTHONPATH whenever you run
      Python and want to use the package(s) you are installing.)

    * You can set up the installation directory to support ".pth" files by
      using one of the approaches described here:

      https://pythonhosted.org/setuptools/easy_install.html#custom-installation-locations

    Please make the appropriate changes for your system and try again.

    ----------------------------------------
Command "/home/nalderso/dev/scratch/venv/bin/python -c "import setuptools, tokenize;__file__='/tmp/pip-build-Wc3oaO/stompest/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-fZlXM2-record/install-record.txt --compile --install-headers /home/nalderso/dev/scratch/venv/include/site/python2.7/stompest --home=/tmp/tmpHNVOP0" failed with error code 1 in /tmp/pip-build-Wc3oaO/stompest

Am I doing something wrong, or is this an issue with pip ?

Answer 1

It works when you do this:

import site
site.addsitedir('some_dir')

See https://docs.python.org/2/library/site.html#site.addsitedir

I found this answer in a post by Matt Iversen (Ivoz) in this pip issue . Note that talk in this issue continues about some corner cases you might run into.