`pip uninstall` fails when called in the package's source dir

Environment

• pip version: 19.1.1
• Python version: 3.6.8
• OS: macOS

Description

I installed a local package, spam, using python3 -m pip install --user .. If I try to uninstall my package when the package folder is in the current directory, I get the following:

$ pwd
/Users/me/spam
$ ls
README.md  setup.cfg  setup.py  test  tox.ini  spam
$ python3 -m pip uninstall --verbose spam
Not sure how to uninstall: spam 0.0.1 - Check: /Users/me/spam  # this line only shown with --verbose flag
Can't uninstall 'spam'. No files were found to uninstall.

The uninstall completes successfully when I run it from a different directory:

$ cd \tmp && python3 -m pip uninstall --verbose spam
# successfully uninstalls...

Expected behavior I did not expect uninstall to be sensitive to the contents of the local directory. If this is the expected behavior for technical reasons, I would change the stderr message Can't uninstall 'spam'. No files were found to uninstall. to be more helpful in indicating that the failure could be because there is a local folder with the target package’s name.

[reynoldsnlp]

@pfmoore I think your edited message is definitely an improvement (and would have saved me some time), but I would go even further. What about something more instructive, like Can't uninstall 'spam' (in current directory). No files were found to uninstall.\nTo uninstall 'spam' from the system library, run the same command from a directory without a 'spam' directory. (and change system library if there is a more precise term). Is that too verbose?

It seems like the only time someone would ever bump up against this message is if they were in a similar situation to me. I may be wrong, but uninstalling from the current directory like cd path/to/site-packages && python3 -m pip uninstall spam seems like a marginal use case, and if someone knows enough to be doing that, then a message tuned for mouth-breathers like me will not confuse them.

It seems that most users just assume – like I did 😉 – that uninstall is going to magically go find the package in the system library.

[piotr-dobrogost]

With pip list I get also the package in the current working directory, which makes sense because it is available there.

After change in https://github.com/pypa/pip/pull/7955 you should not get this package unless your PYTHONPATH includes current working directory.