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.
* Fix flask render_template and render_template_string stubs
* Add types for flask view function
* Import TracebackType from the right location
* Switch to bound typevar in route decorator stub
* Change render_template and render_template_string parameters to Text
This includes two things to sync up with recent runtime updates:
* Move `Final`, `@final`, `Literal`, and `TypedDict` to `typing` (`typing_extensions` still defines or re-exports them)
* Rename `@typing.runtime` to `@typing.runtime_checkable`, while keeping `@runtime` as a backwards-compatible alias in `typing_extensions`.
Since these properties do not have a setter, be explicit with the
`@property` decorator. This will allow type checkers to see that
assignment of these attributes is an error.
See https://github.com/python/typeshed/pull/3027#discussion_r289623016
for some related context.
The main purpose of this change is to get the stubs into a
form that pytype will support with its next release. Since
these stubs already mostly use fully qualified names, this
will also increase consistency.
This also makes the flask stubs that depend on click parseable.
* In pytype_test, only parse files with the .pyi extension.
(There's a README in third_party/2and3/click/.)
* Annotate with ContextManager rather than using the
contextmanager decorator. This is shorter, removes a
dependency, and gets rid of the slight weirdness of a
decorator needing to be evaluated in a stub.
* Fix non-stub things.
Depending on if a "stream" or the "encoding" is given, the functions
either return None, str/unicode or bytes.
Use @overload fix distinguish those cases.
Also fix the functions using **kwds as they delegate their work to the
more generic functions: copy their signatures.
* yaml.dump(): Drop distinguishing encoding
As far as I know it's currently impossible to use "overloads with return
types depending on optional arguments" (Issue #5621). As "encoding" is
in the middle of 11 optional arguments, it would require ~ 2^6 overloads
for each of those 6 functions.
For now just return Any and wait for Issue #5621 to get fixed.
