global pip install doesn't clean up temporary directories

[ronaldoussoren]

"pip install" creates a working directory in /tmp ("/tmp/pip-build-$USERNAME"). This directory is not removed when the installation is done, and still contains the extracted archive for the package you installed without version information. That is, after 'pip install foo==1.0' the directory /tmp/pip-build-$USER still exists, and contains a subdirectory 'foo'.

When the user doesn't clean up the directory manually pip refuses to install updates (pip install foo==2.0), for example with "pip install lxml==3.2.1":

pip install lxml==3.2.1
Downloading/unpacking lxml==3.2.1
  Running setup.py egg_info for package lxml
    /opt/python2.7/lib/python2.7/distutils/dist.py:267: UserWarning: Unknown distribution option: 'bugtrack_url'
      warnings.warn(msg)
    Building lxml version 3.2.0.
    Building without Cython.
    Using build configuration of libxslt 1.1.15
    Building against libxml2/libxslt in the following directory: /usr/lib

    warning: no files found matching '*.txt' under directory 'src/lxml/tests'
  Requested lxml==3.2.1, but installing version 3.2.0

This is rather annoying, as even when pip claims to have finished I still have to verify that it actually installed the package I requested instead of some older version that happens to be the last version I tried to install earlier.

[qwcode]

there's recent commits (#865) in the develop branch for proper build cleanup when operating in a virtualenv.

the "pip-build-username" pattern is for global pip installs, and I just checked and it's still not being cleaned up properly.

adding to 1.4 milestone. I'll look at this

[ronaldoussoren]

Why does the code not use tempfile.mkdtemp to create the working directory? That way the scratch directory is unique and can always be cleaned up. You'd also avoid problems with guessable names in /tmp.

[qwcode]

pip has a legacy of using fixed build dirs, as best I can tell, due to the "workflow" of the --no-install/--no-download options. my intention is to refactor much of this in #906 in v1.5.

1.5 milestone: https://github.com/pypa/pip/issues?milestone=2&state=open

but for v1.4, the quick fix is that /tmp/pip-build-$USERNAME" needs pip's delete marker dropped into it, when it's created, and pip will clean it up. will merge that fix soon.

[qwcode]

closing due to merge of #948
#906 in v1.5 will contain a better fix.