Pip deprecation warnings not displayed by default

[sbidoul]

Description

Following #11229 the pip deprecation warnings are not displayed by default, because DeprecationWarnings are ignored by the default warning filters.

I propose to revert #11229 in pip 22.2.2 and we can think about a better solution for 22.3 or later.

Expected behavior

Pip deprecation warnings should be displayed with a default python installation, otherwise most users won't see them.

pip version

22.2

Python version

3

OS

any

How to Reproduce

...

Output

No response

Code of Conduct

• I agree to follow the PSF Code of Conduct.

[uranusjr]

Copying the problem from #11225. There is currently no good way to suppress pip’s deprecation warnings, even if they are expected for various reasons.

[pradyunsg]

We can subclass from warning, and let user suppress PipDeprecationWarning?

[pradyunsg]

Regardless, I’d prefer we unconditionally show warnings than not show them. ;)

[sbidoul]

FWIW, I've tried this:

❯ python -W 'ignore::pip._internal.utils.deprecation.PipDeprecationWarning' -m pip --version
Invalid -W option ignored: invalid module name: 'pip._internal.utils.deprecation'
...

I've not had time to dig further. So if no better low risk idea shows up I'm going to go ahead with #11333 for 22.2.2 and reopen #11225.

[pradyunsg]

Just ignore PipDeprecationWarning, without any internal module path?

[sbidoul]

Nope, I had tried that too: Invalid -W option ignored: unknown warning category: 'PipDeprecationWarning'.

[pfmoore]

I can reproduce this in a standalone package:

ttt
    __init__.py (contains "class W(Warning): pass")
    __main__.py (contains a print("hi") statement)

❯ py -W ignore::ttt.W ttt
Invalid -W option ignored: invalid module name: 'ttt'
hi

I suspect this is a core Python bug, with -W not handling 3rd party module names for some reason.

[uranusjr]

Ah so the syntax seems pretty weird. https://docs.python.org/3/using/cmdline.html#cmdoption-w

So I think -W ignore::PipDeprecationWarning:pip._internal.utils.deprecation should work?

(I wonder if it’s worthwhile to make PipDeprecationWarning a top-level import so a user can write ignore:PipDeprecationWarning:pip)

[pradyunsg]

❯ python -W ignore::PipDeprecationWarning:pip._internal.utils.deprecation -m pip --version
Invalid -W option ignored: unknown warning category: 'PipDeprecationWarning'
pip 22.3.dev0 from /Users/pradyunsg/Developer/github/pip/src/pip (python 3.10)