#11655 Remove use of pkg_resources

[ofek]

Scope and purpose

Fixes #11655

See #11728 (comment)

[ofek]

https://docs.python.org/3.9/library/importlib.metadata.html

[glyph]

Looks fine, but I'm not sure it's going to pass coverage. I'll switch the merge base to trunk now that it's reviewed, and hopefully that will run through CI

[glyph]

Sigh. Okay. Codecov is too smart for our trickery.

Which actually raises the question: why are we doing this faffing with packaging metadata, anyway? We used to do this because we wanted to be as similar as possible to the stubs that pip install generated, but looking at a modern virtualenv, I see the stubs look like this:

#!/Users/glyph/.virtualenvs/Twisted/bin/python
# -*- coding: utf-8 -*-
import re
import sys
from twisted.scripts.trial import run
if __name__ == '__main__':
    sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
    sys.exit(run())

So that implies that this should instead simply be:

    from twisted.scripts.trial import run
    sys.exit(run())

Is there any reason not to do that?

(Suggestion in multiple parts below)

[ofek]

very true

[glyph]

Part 1: no need for this package at all

Suggested change

	if sys.version_info >= (3, 8):
	from importlib.metadata import distribution
	else:
	from importlib_metadata import distribution

[glyph]

Part 2: let's not overcomplicate things

Suggested change

	sys.exit(
	next(
	ep
	for ep in distribution("twisted").entry_points
	if (ep.group, ep.name) == ("console_scripts", "trial")
	).load()()
	)
	from twisted.scripts.trial import run
	sys.exit(run())

[glyph]

Oops. Whatever we do here, twisted/__main__.py also needs to be fixed in the same way.

[glyph]

Made a suggestion to keep the script import inside the if __name__ block, but otherwise, if this passes tests let's land.

[ofek]

rebased

[adiroiban]

Many thanks @ofek for the fix and @glyph for the review.

I have merged this on behalf of @glyph :)

[glyph]

Thanks @adiroiban !