Merge stdlib/{2,3}/os/{__init__,path}.pyi

[euresti]

This is the full merge of os and os.path in one PR. With this the files are identical and could easily be renamed into stdlib/2and3

[gvanrossum]

So this supersedes #1103 right? Does it contain the changes requested in the review there? Can you close #1103?

[gvanrossum]

So there's still a problem here -- are you aware that there's also a definition of stat_result in posix.pyi? There are quite a few duplicates there -- it doesn't matter for the constants (e.g. O_APPEND) but it does match for the classes, since I've found code (in our own codebase) using posix.stats_result in type annotations. I expect it may be ditto for posixpath.pyi.

[gvanrossum]

Anther issue: I found a few expressions like this:

os.stat(path)[stat.ST_MODE]  # E: Tuple index must be an integer literal

Now arguably this should be replaced with

os.stat(path).st_mode

But the old code should still be considered valid IMO.

I'm not sure how to fix this other than making mypy somehow recognize constant definitions like ST_MODE = 0 in stats.pyi. (BTW the constants there seem wrong -- to work with the NamedTuple they should be the correct indices, if we fix mypy to support that.)

[gvanrossum]

See discussion in main thread of PR.

[JelleZijlstra]

This merge conflicts now because I merged #1103.

Currently the stubs for posix.pyi in Python 2 are fairly complete, but the ones in Python 3 just re-export stat_result from os.pyi. In reality the os module mostly re-exports names from posix (or from nt on windows?), so maybe ideally the os stub would just have a big from posix import x as x, y as y.

[euresti]

I tried bringing everything into posix.pyi but hit a small hitch if I wanted to just do from posix import *, which is what os.py does in cpython, basically posix.environ is a Dict[bytes, bytes] but os.environ is a different beast and mypy gives me an import error. Technically, like 90% of the methods and constants in os are imported from posix so I'd rather not do from posix import O_CREATE, S_OK, etc any tips on handling this?

[JelleZijlstra]

I see, that's unfortunate. I can't really think of a better solution than repeating all the names.

[euresti]

I'm gonna close this PR and split it up into smaller parts.