Pip not uninstalling previous versions when installing directly from a wheel path/url

[agronholm]

Reproducible with pip 1.5.6 as follows:

1. create and activate a virtualenv
2. install wheel
3. create a trivial setup.py
4. run bdist_wheel
5. install the wheel
6. bump up the version in setup.py
7. run bdist_wheel again
8. install the newer version

Contents of setup.py used:

from setuptools import setup

setup(
  name='Foo',
  version='1.0.0'
)

The previous version remains in site-packages and "Foo" can be uninstalled twice.
If I install Foo as a wheel first and the next version as sdist, the old version is uninstalled properly.
If I install the sdist first and wheel later, I get two Foos in site-packages.
Thus I conclude that wheel installation does not check for an existing installation.
I'm not even sure this bug belongs to pip.

[qwcode]

yes, I can confirm this.
It's specifically when installing from wheel archives directly (local paths or urls)
i.e. it's not wheels in general (for example when using specifiers that only happen to install wheels from indexes or find-links)

btw, installing directly from sdist does not have this problem.

I'll take a look at fixing this.

[dstufft]

This is probably a big enough bug to issue another 1.5.x I think?

[agronholm]

+1 for another 1.5.x

[qwcode]

I think I have a fix for this.
I can post it tomorrow with tests.

[pfmoore]

If we're doing another 1.5.x, can we revendor distlib? I'll try to get together a PR for that this evening, if nobody beats me to it :-)

[dstufft]

Sure.

[Ivoz]

Added a 1.5.7 to organise things to put in it~

[qwcode]

afaict, this has been a wheel bug from the beginning, so not sure it really qualifies for a patch release, but if people want to do a 1.5.7 for this, that's fine.

[qwcode]

if we're really doing the 1.5.7, I need to redo #1831 against 1.5.X

[Ivoz]

I don't have much of an opinion on whether or not to do more point releases on 1.5, but organising issues into milestones doesn't cost anything so it's just a why not, in case :)