Remove a package with its dependencies that are not required by other packages

[DarkSuniuM]

What's the problem this feature will solve?
Uninstall a package with its dependencies that are not required by any other package

Describe the solution you'd like
A flag like --remove-dependencies that user can use with pip uninstall <package_name>

For example, I wrongly installed a package (Virtualenv or SystemGlobal) and then I realized I don't need that, Only footage I can see is the log of installation that says which packages are installed after I ran pip install jupyter, There is no way to remove the package and its dependencies!

[benoit-pierre]

One thing that might make implementing this functionality problematic: there's no record of the extras used when a package was installed (which is also a problem with pip check).

[uranusjr]

Another piece missing is what packages are “top-level”. Say I install Django, and then “wrongly” install django-debug-toolbar, I wouldn’t want the hypothetical pip uninstall --remove-dependencies django-debug-toolbar to remove Django (and its dependencies).

[pradyunsg]

This is something that we might want to do moving forward but we would need to first fix the issues with installed package metadata that @benoit-pierre and @uranusjr point out.

IMO The best path forward here would be to resolve those issues and then proceed with the discussion on this feature.

[DarkSuniuM]

This is something that we might want to do moving forward but we would need to first fix the issues with installed package metadata that @benoit-pierre and @uranusjr point out.

IMO The best path forward here would be to resolve those issues and then proceed with the discussion on this feature.

I'm not a professional or a well experienced developer, But I guess each package has a requirements.txt file or something like that, is that right? If so, can't we just use them to lookup the dependencies and check them against other installed packages?

[DarkSuniuM]

Another piece missing is what packages are “top-level”. Say I install Django, and then “wrongly” install django-debug-toolbar, I wouldn’t want the hypothetical pip uninstall --remove-dependencies django-debug-toolbar to remove Django (and its dependencies).

A Metadata file, can has a key like installed-by, The key can be null, or it can be the name of the package that installed the package, No one will install django-debug-toolbar to install django, users will install django, and then install other packages like django-debug-toolbar.
When django is installed first, the installed-by key in the metadata file should be null, and then if u uninstall django-debug-toolbar, then the django package which installed before and is a dependency of django-debug-toolbar won't be uninstalled, but the packages that has installed-by key and the value is django-debug-toolbar will be uninstalled.. I guess it will work well this way

[uranusjr]

I read through the relevent PEPs and realised that, although pip does not implement it, there is already a mechanism to record whether a package is “user-installed” (and should not be removed even if no-one depends on it)—namely, the REQUESTED file in PEP 376. The extras are however still difficult to handle, and would require some extra metadata. The CLI would also need some extra work to sort out edge cases like this:

pip install A[x]
pip install A[y]
pip uninstall --remove-dependencies A     # What should it uninstall?
pip uninstall --remove-dependencies A[x]  # This is not currently possible.

[pradyunsg]

Yep. I can confirm that I had the same findings earlier.

I'd started a discussion about storing the extras on distutils-sig a while back but haven't had the time to follow through on it.

[pradyunsg]

To reiterate, IMO until we store the missing bits information on the filesystem or in an internal database, this feature can't be meaningfully discussed.