typing: Session.__init__

[blueyed]

Pulled out of #6491.

[nicoddemus]

Out of curiosity, is considered good practice to annotate the return value of all functions even if they return None?

[blueyed]

It has to be for the function to be considered to be typed.
I've amended it to also type config (the arg) explicitly, although done via base class.

[nicoddemus]

I see, thanks makes sense, it is the only annotation.

Now it brings the next question, is:

def __init__(self, config: Config):

enough for it to be considered typed?

[blueyed]

Yes (AFAIK), but might fail with strict options etc?! /cc @bluetech

[blueyed]

btw: reveal_type(var) is very useful in that regard.

[bluetech]

Apparently sometimes the key can be tuple so the type is not exactly correct:

pytest/src/_pytest/main.py

Lines 574 to 579 in ad02f6f

	key = (type(x), x.fspath)
	if key in self._node_cache:
	yield self._node_cache[key]
	else:
	self._node_cache[key] = x
	yield x

I am working on some annotations and will include a fix for this, hopefully tomorrow.