This pull request is a follow-up to https://github.com/python/mypy/issues/7214.
In short, within that mypy issue, we found it would be helpful to
determine between contextmanagers that can "swallow" exceptions vs ones
that can't. This helps prevent some false positive when using flags that
analyze control flow such as `--warn-unreachable`. To do this,
Jelle proposed assuming that only contextmanagers where the `__exit__`
returns `bool` are assumed to swallow exceptions.
This unfortunately required the following typeshed changes:
1. The typing.IO, threading.Lock, and concurrent.futures.Executor
were all modified so `__exit__` returns `Optional[None]` instead
of None -- along with all of their subclasses.
I believe these three types are meant to be subclassed, so I felt
picking the more general type was correct.
2. There were also a few concrete types (e.g. see socketserver,
subprocess, ftplib...) that I modified to return `None` -- I checked
the source code, and these all seem to return None (and don't appear
to be meant to be subclassable).
3. contextlib.suppress was changed to return bool. I also double-checked
the unittest modules and modified a subset of those contextmanagers,
leaving ones like `_AssertRaisesContext` alone.
- Adding optional to _FILE for stderr + stdout arguments to subprocess functions
- Sometimes you might want subprocess commands to be quiet and other time print the output
* Fix incorrect usage of AnyStr
- sqlite3 was using Union[bytes, AnyStr], which doesn't make sense
- The urllib functions I changed accept either bytes or str for their "safe"
argument
- Also added supports for PathLike to pstats
- Remove some unused imports of AnyStr
* pstats: python 2 accepts unicode
* Improve types for CalledProcessError
This adds union types in the constructor to account for parameters that
might be either byte strings or unicode strings. At the same time, this
*removes* specific types from the user-accessible fields, to avoid the
need for users to at every use site specify which types their particular
instance was instantiated with.
* remove 'moral' comments; add List import; change 'str' to 'Text'
* import Text
* List -> Sequence; reinsert 'moral' comments
* Regularize string types everywhere
This defines _TXT and _CMD aliases, and uses them everywhere applicable.
Also brings the _FILE alias to python3.
* fix typo; possibly fix indentation
* remove trailing comma, which caused problems in python 2 tests
* fix py2 outputs to be bytes; tweak descriptive comments; remove one AnyStr
* Add `None` to type union for `subprocess.Popen.communicate` stub's `input` parameter.
* subprocess.communicate `input` annotated as `Optional[AnyStr]` for both 2.7 and 3.x; `timeout` as `Optional[float]`.
