BUG: crash: collections.abc.Callable does not allow tuple in Python 3.10

[StefanRickli]

This PR is about the following line:

pdoc/pdoc/__init__.py

Line 1358 in 65342ae

a = a.__origin__[(args[:-1], args[-1])]

In Python 3.10, _CallableGenericAlias.__new__ does an explicit check for list and not (tuple | list), so the current code crashes in the except clause when the args tuple is sliced into a new tuple.

Here's the type check in Python 3.10:
https://github.com/python/cpython/blob/8773554b717cfb08b4bd11a927813f4ed74762c7/Lib/_collections_abc.py#L433

The same line in Python 3.11:
https://github.com/python/cpython/blob/f0895aa9c1d40d0add673cc51bd143556e22100a/Lib/_collections_abc.py#L433

I suggest we explicitly convert the first argument to __origin__ to a list for backwards compatibility. Unittests failed before, now they pass.

[kernc]

Thanks for a clear bug report and the provided solution!

Unittests failed before, now they pass.

Since we do test on Python 3.9

pdoc/.github/workflows/ci.yml

Line 12 in 65342ae

python-version: ['3.9', '>=3']

what unit tests are that; do you mean yours?

I'm guessing this would otherwise be covered by this, CI-skipped test?

pdoc/pdoc/test/__init__.py

Lines 131 to 134 in 65342ae

	@unittest.skipIf(sys.version_info < (3, 10),
	'HACK: _formatannotation() changed return value in Py3.10')
	def test_project_doctests(self):
	doctests = doctest.testmod(pdoc)

[StefanRickli]

what unit tests are that; do you mean yours?
I'm guessing this would otherwise be covered by this, CI-skipped test?

pdoc/pdoc/test/__init__.py

Lines 131 to 134 in 65342ae

	@unittest.skipIf(sys.version_info < (3, 10),
	'HACK: _formatannotation() changed return value in Py3.10')
	def test_project_doctests(self):
	doctests = doctest.testmod(pdoc)

Yes, unittests on Python3.10, no modifications.
Skipping your highlighted test indeed makes the unittests pass even with the bug present.

Seems like all the holes in the Swiss cheese are aligning in this case.

What makes it even more crazy is that Python3.10 currently is the only supported Python version that has the narrower type check, and the looser (tuple | int) check was even there 3 years ago, and for some reason patched out. Maybe an oversight.