[prerelease] pytest.TmpdirFactory is not importable anymore

Discovered in https://github.com/ClearcodeHQ/pytest-postgresql/issues/533#issuecomment-999567968 via #9415:

Doing e.g. python3 -c "import pytest; pytest.TempdirFactory" fails since 5e883f51959f900fcf985493ce2d09e07bad7e00. This is a bit similar to #9396, but #9400 won’t help with this one.

Test modules often use pytest.TempdirFactory for type annotations - in fact, that’s why that was added in 6.2.0.

However, it being set from a plugin means that:

a) Test modules aren’t even importable anymore outside of pytest - in case of pytest-postgresql, this breaks an importability check, but I can imagine various other things breaking… b) Perhaps more importantly, static analysis in IDEs or tools like mypy aren’t aware anymore that the attribute exists - however, after all, that’s the whole point of it existing, and lots of projects use it that way. (Some import it from _pytest.tmpdir, probably because they did that before 6.2.0 - I’m not too worried about those, they knew what they’re in for)

Reproducer:

from pytest import TempdirFactory

def test_nothing(tmpdir: TempdirFactory):
    pass

Fails with mypy:

test_x.py:1: error: Module "pytest" has no attribute "TempdirFactory"; maybe "TempPathFactory"?
Found 1 error in 1 file (checked 1 source file)

What to do? I suppose as a stop-gap until we want to distribute the plugin independently from pytest, we could import the class from the plugin or so?

[RonnyPfannschmidt]

Let’s provide the attribute, for python 3.7+ we can provide a deprecation using the module getattr special method

[nicoddemus]

Also, please don’t feel bad for it - you worked on a lot of very tricky topics for this release (which is very appreciated!), so it’s somewhat natural that regressions happen to bisect to one of your commits - let us know if we can help somewhere, and thanks for handling the fallout!

I second that! 👍