The following code produces an error in mypy:
import asyncio
from asyncio.subprocess import PIPE
async def main() -> None:
proc = await asyncio.create_subprocess_shell("ls -l", stdout=PIPE)
assert proc.stdout is not None
async for line in proc.stdout:
print(line.decode())
await proc.wait()
asyncio.run(main())
$ mypy --strict file.py
file.py:8: error: "StreamReader" has no attribute "__aiter__" (not async iterable)
This commits fixes this by adding __aiter__/__anext__ methods that are
needed for async iterator protocol.
This is a follow-up on #4232. memoryview, hashlib, and hmac are updated
to use ReadableBuffer type instead of their own home-spun unions of
bytes, bytearray and whatever else each use case used. mmap is being
handled in #4244, and I'll leave BinaryIO for another day (or possibly
another person) because it's going to require some messy code
duplication because the relevant methods are defined in IO[AnyStr].
There's one corner case I'm not quite sure how best to handle: the
documentation for hmac.digest claim that the parmaeters have the same
meanings as in hmac.new, but in CPython the latter has an explicit check
that `key` is bytes or bytearray while the former works with a
memory-view. For now I've matched the documentation.
Also, the documentation for HMAC.update says that `msg` can be any type
supported by hashlib from Python 3.4; but I can't see anything in the
Python 2.7 implementation that would prevent it also taking bytes-like
objects, so I've not tried to treat Python 2 any different to Python 3.
* Update mmap stubs for newer Python versions
Based on the Python stdlib documentation:
- Since Python 3.5, mmap.{find,rfind,write} all accept any bytes-like.
I've used the _typeshed.ReadableBuffer alias defined in #4232.
- Since Python 3.6, mmap.write returns the number of bytes written.
- Since Python 3.3, mmap.read allows None as the parameter; while in
Python 2 the argument cannot be omitted.
* Further clean up mmap.pyi
Use the fact that Python 3.0-3.4 are no longer supported to clean up the
version-dependent logic. Functions that always have different signatures
in Python 2/3 are moved from the base _mmap[bytes] to the mmap subclass.
Since typing doesn't yet have a way to express buffer protocol objects
(python/typing#593), various interfaces have ended up with a mish-mash
of options: some list just bytes (or just bytearray, when writable),
some include mmap, some include memoryview, I think none of them include
array.array even though it's explicitly mentioned as bytes-like, etc. I
ran into problems because RawIOBase.readinto didn't allow for
memoryview.
To allow for some uniformity until the fundamental issue is resolved,
I've introduced _typeshed.ReadableBuffer and _typeshed.WriteableBuffer,
and applied them in stdlib/3/io.pyi as an example. If these get rolled
out in more places, it will mean that we have only one place where they
have to get tweaked in future, or swapped out for a public protocol.
This unfortunately does have the potential to break code that inherits
from RawIOBase/BufferedIOBase and overrides these methods, because the
base method is now more general and so the override now needs to accept
these types as well (which is why I've also updated gzip and lzma).
However, it should be a reasonably easy fix, and will make the
downstream annotations more correct.
A few comments between imports were removed or moved to the top of the
import block, due to behavioral differences between black and isort. See
psf/black#251 for details.
In two instances @overloads at the top of the file needed to be moved
due to psf/black#1490.
write() is inherited from IO[bytes], where it's defined as
`def write(self, s: AnyStr) -> int: ...`. If AnyStr is bytes,
this should accept bytes, bytearray, and memoryview, so the
overload is unnecessary.
Closes: #4201
