Use context managers for disable_errors()

[dixith]

Description

This PR fixes one of the issue reported in #1184

Test Plan

Since this change is coding style change, new cases are not added.

[JelleZijlstra]

Thanks for your contribution!

[JelleZijlstra]

Should use try-finally

[dixith]

Thank you for the review @JelleZijlstra

yield should be inside try-finally?

@contextmanager
def disable_errors(self) -> Iterator[None]:
    self.disable_count += 1
    try:
        yield
    finally:
        pass
    self.disable_count -= 1

[JelleZijlstra]

And the -= 1 should be in the finally block. The point is to make sure the cleanup code always happens.

[dixith]

Got it.

[dixith]

@JelleZijlstra Now that we have try-finally inside enable_errors() below try-finally is redundent right? Can be removed?

mypy/mypy/checkexpr.py

Line 2811 in 8860575

right_type = self.analyze_cond_branch(right_map, e.right, left_type)

if right_map is None:
  with self.msg.disable_errors():
     try:
        right_type = self.analyze_cond_branch(right_map, e.right, left_type)
     finally:
        pass

[JelleZijlstra]

A try-finally with an empty finally block doesn't do anything useful, so yes you can remove it.

[JelleZijlstra]

Can this method be removed?

[dixith]

Removed enable_errors()

[dixith]

Getting below error.
mypy/checkexpr.py:2772: error: Local variable 'right_map' has inferred type None; add an annotation

[dixith]

@JelleZijlstra

Getting below error. Do you ahve any suggestions?
mypy/checkexpr.py:2772: error: Local variable 'right_map' has inferred type None; add an annotation

[JelleZijlstra]

Sorry, I'm not too familiar with that code. I'd try adding an annotation though, as the error message suggests.

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

flake8 (https://github.com/pycqa/flake8.git)
+ src/flake8/checker.py:471: error: "Optional[FileProcessor]" has no attribute "build_ast"
+ src/flake8/checker.py:497: error: "Optional[FileProcessor]" has no attribute "build_logical_line"
+ src/flake8/checker.py:500: error: "Optional[FileProcessor]" has no attribute "update_state"
+ src/flake8/checker.py:505: error: "Optional[FileProcessor]" has no attribute "update_checker_state_for"
+ src/flake8/checker.py:518: error: "Optional[FileProcessor]" has no attribute "next_logical_line"
+ src/flake8/checker.py:526: error: "Optional[FileProcessor]" has no attribute "update_checker_state_for"
+ src/flake8/checker.py:561: error: "Optional[FileProcessor]" has no attribute "generate_tokens"
+ src/flake8/checker.py:599: error: "Optional[FileProcessor]" has no attribute "reset_blank_before"
+ src/flake8/checker.py:602: error: "Optional[FileProcessor]" has no attribute "visited_new_blank_line"
+ src/flake8/checker.py:603: error: "Optional[FileProcessor]" has no attribute "delete_first_token"
+ src/flake8/checker.py:633: error: "Optional[FileProcessor]" has no attribute "inside_multiline"
+ src/flake8/checker.py:634: error: "Optional[FileProcessor]" has no attribute "split_line"

pydantic (https://github.com/samuelcolvin/pydantic.git)
+ pydantic/validators.py:195: error: Unsupported operand types for < ("int" and "None")  [operator]
+ pydantic/validators.py:199: error: Unsupported operand types for > ("int" and "None")  [operator]

prefect (https://github.com/PrefectHQ/prefect.git)
+ src/prefect/environments/execution/dask/cloud_provider.py:140: error: "None" has no attribute "scheduler"


pandas (https://github.com/pandas-dev/pandas.git)
+ pandas/io/html.py:1092: error: Unsupported operand types for > ("int" and "None")  [operator]
+ pandas/io/html.py:1092: error: Unsupported operand types for > ("int" and "Sequence[int]")  [operator]
+ pandas/io/html.py:1092: error: Unsupported operand types for > ("int" and "slice")  [operator]
+ pandas/io/html.py:1092: note: Left operand is of type "Union[int, Sequence[int], slice, None]"
+ pandas/tseries/holiday.py:451: error: Value of type "None" is not indexable  [index]

aioredis (https://github.com/aio-libs/aioredis.git)
+ aioredis/client.py:3774: error: "Optional[Connection]" has no attribute "read_response"
+ aioredis/client.py:3779: error: "Optional[Match[str]]" has no attribute "groups"


tornado (https://github.com/tornadoweb/tornado.git)
+ tornado/web.py:1715: error: "None" has no attribute "done"

poetry (https://github.com/python-poetry/poetry.git)
+ poetry/utils/appdirs.py:27: error: "Union[str, Path]" has no attribute "startswith"
+ poetry/utils/env.py:1236: error: "Optional[Command]" has no attribute "finalize_options"
+ poetry/utils/env.py:1310: error: "Union[str, int]" has no attribute "strip"
+ poetry/utils/env.py:1321: error: "Union[str, int]" has no attribute "strip"
+ poetry/utils/env.py:1367: error: "Union[int, str]" has no attribute "strip"
+ poetry/version/version_selector.py:54: error: "None" has no attribute "version"
+ poetry/publishing/uploader.py:157: error: "Optional[Match[str]]" has no attribute "group"

spark (https://github.com/apache/spark.git)
+ python/pyspark/shuffle.py:602: error: "Optional[Any]" has no attribute "tell"
+ python/pyspark/shuffle.py:606: error: "Optional[Any]" has no attribute "tell"

pytest (https://github.com/pytest-dev/pytest.git)
+ src/_pytest/fixtures.py:1107: error: "Union[Callable[..., FixtureValue], Callable[..., Generator[FixtureValue, None, None]]]" has no attribute "__get__"  [attr-defined]
+ src/_pytest/fixtures.py:1121: error: "Union[Callable[..., FixtureValue], Callable[..., Generator[FixtureValue, None, None]]]" has no attribute "__get__"  [attr-defined]

isort (https://github.com/pycqa/isort.git)
+ isort/_vendored/toml/decoder.py:888: error: "Optional[Match[str]]" has no attribute "groups"

graphql-core (https://github.com/graphql-python/graphql-core.git)
+ src/graphql/language/block_string.py:52: error: Unsupported operand types for < ("int" and "None")

[JelleZijlstra]

Sorry for dropping this! We ended up merging #10569 instead.