`pip uninstall -y <pkg>` should warn when an extra file will not be removed

[zanieb]

Description

pip uninstall -y <pkg> does not display warnings for files it does not remove, which means you can think an uninstall was successful while you are left in a bad state due to lingering files.

Expected behavior

pip uninstall -y <pkg> should display warnings for files that are not removed. This information is already shown for pip uninstall <pkg>.

e.g.

WARNING: Did not remove `.venv/lib/python3.11/site-packages/idna-3.6.dist-info/FOO

pip version

23.3.2

Python version

3.11.4

OS

macOS

How to Reproduce

Here's a script to reproduce in a clean environment:

python -m venv .venv
source .venv/bin/activate
python -m pip install pip==23.3.2 > /dev/null 2>&1

set -eux

SITE_PACKAGES=$(python -c 'import site; print(site.getsitepackages()[0])')
pip install --no-cache idna==3.6 > /dev/null 2>&1

# Create an extra file, this is "silly" but you can end up in this state without touching `site-packages` manually
touch $SITE_PACKAGES/idna-3.6.dist-info/FOO

# Shows "would not remove" warning
yes | pip uninstall idna

pip install --no-cache idna==3.6 > /dev/null 2>&1

# Does not show warning
pip uninstall -y idna

rm -rf .venv

Output

++ python -c 'import site; print(site.getsitepackages()[0])'
+ SITE_PACKAGES=.venv/lib/python3.11/site-packages
+ pip install --no-cache idna==3.6
+ touch .venv/lib/python3.11/site-packages/idna-3.6.dist-info/FOO
+ yes
+ pip uninstall idna
Found existing installation: idna 3.6
Uninstalling idna-3.6:
  Would remove:
    .venv/lib/python3.11/site-packages/idna-3.6.dist-info/*
    .venv/lib/python3.11/site-packages/idna/*
  Would not remove (might be manually added):
    .venv/lib/python3.11/site-packages/idna-3.6.dist-info/FOO
Proceed (Y/n)?   Successfully uninstalled idna-3.6
+ pip install --no-cache idna==3.6
+ pip uninstall -y idna
Found existing installation: idna 3.6
Uninstalling idna-3.6:
  Successfully uninstalled idna-3.6
+ rm -rf .venv

Code of Conduct

• I agree to follow the PSF Code of Conduct.

[pfmoore]

How do you know a file is "extra"? If the package is a namespace package, there could easily be legitimate files from another package in the same directory.

I'm not against this idea in principle, but I'm skeptical anyone can come up with an implementable definition of the "right" behaviour.

[zanieb]

That's fair! I'm just looking to match the behavior of pip uninstall without the -y flag here e.g. explain which files or directories are not removed during uninstall. I agree there are legitimate cases where the files should remain.