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
The return type of `__eq___` should be `bool`.
Otherwise, `mypy --disallow-any-unimported --no-silence-site-packages`
fails because the return type becomes `Union[bool, Any]` due to an
unfollowed import.
* make io classes inherit from typing IO classes
This makes these classes usable if type annotations are given as "IO"
or "TextIO". In the future, we'll then be able to move open() to
return a concrete class instead (#3951).
* open: introduce concrete return types
Fixes#3951.
We use the values of the "mode" and "buffering" arguments to figure out
the concrete type open() will return at runtime. (Compare the CPython
code in https://github.com/python/cpython/blob/master/Modules/_io/_iomodule.c#L231.)
This makes these classes usable if type annotations are given as "IO"
or "TextIO". In the future, we'll then be able to move open() to
return a concrete class instead (#3951).
* compileall: add stripdir, prependdir and limit_sl_dest
* compileall: compile_dir's default value is now None
* compileall: update for current py39 (as of beta1)
Co-authored-by: hauntsaninja <>
