[`flake8-pyi`] Implement PYI026 #5844

LaBatata101 · 2023-07-17T22:52:00Z

Summary

Checks for typehint.TypeAlias annotation in type aliases. See original source.

$ flake8 --select Y026 crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.pyi
crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.pyi:4:1: Y026 Use typing_extensions.TypeAlias for type aliases, e.g. "NewAny: TypeAlias = Any"
crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.pyi:5:1: Y026 Use typing_extensions.TypeAlias for type aliases, e.g. "OptinalStr: TypeAlias = typing.Optional[str]"
crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.pyi:6:1: Y026 Use typing_extensions.TypeAlias for type aliases, e.g. "Foo: TypeAlias = Literal['foo']"
crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.pyi:7:1: Y026 Use typing_extensions.TypeAlias for type aliases, e.g. "IntOrStr: TypeAlias = int | str"
crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.pyi:8:1: Y026 Use typing_extensions.TypeAlias for type aliases, e.g. "AliasNone: TypeAlias = None"

$ ./target/debug/ruff --select PYI026 crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.pyi --no-cache
crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.pyi:4:1: PYI026 Use `typing.TypeAlias` for type aliases in `NewAny`, e.g. "NewAny: typing.TypeAlias = Any"
crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.pyi:5:1: PYI026 Use `typing.TypeAlias` for type aliases in `OptinalStr`, e.g. "OptinalStr: typing.TypeAlias = typing.Optional[str]"
crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.pyi:6:1: PYI026 Use `typing.TypeAlias` for type aliases in `Foo`, e.g. "Foo: typing.TypeAlias = Literal["foo"]"
crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.pyi:7:1: PYI026 Use `typing.TypeAlias` for type aliases in `IntOrStr`, e.g. "IntOrStr: typing.TypeAlias = int | str"
crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.pyi:8:1: PYI026 Use `typing.TypeAlias` for type aliases in `AliasNone`, e.g. "AliasNone: typing.TypeAlias = None"
Found 5 errors.

ref: #848

Test Plan

Snapshots, manual runs of flake8.

## What it does Checks for `typehint.TypeAlias` annotation in type aliases. ## Why is this bad? It makes harder for someone reading the code to differentiate between a value assignment and a type alias. ## Example ```python IntOrStr = int | str ``` Use instead: ```python IntOrStr: TypeAlias = int | str ```

github-actions · 2023-07-17T23:37:52Z

PR Check Results

Ecosystem

ℹ️ ecosystem check detected changes. (+2, -0, 0 error(s))

typeshed (+2, -0)

+ stdlib/builtins.pyi:1664:1: PYI026 Use `typing.TypeAlias` for type alias, e.g., `_SupportsSomeKindOfPow: typing.TypeAlias = _SupportsPow2[Any, Any] | _SupportsPow3NoneOnly[Any, Any] | _SupportsPow3[Any, Any, Any]`
+ stdlib/builtins.pyi:220:1: PYI026 Use `typing.TypeAlias` for type alias, e.g., `_LiteralInteger: typing.TypeAlias = _PositiveInteger | _NegativeInteger | Literal[0]`

Rules changed: 1

Rule	Changes	Additions	Removals
PYI026	2	2	0

Benchmark

Linux

group                                      main                                   pr
-----                                      ----                                   --
formatter/large/dataset.py                 1.00     11.0±0.03ms     3.7 MB/sec    1.00     10.9±0.03ms     3.7 MB/sec
formatter/numpy/ctypeslib.py               1.00      2.2±0.00ms     7.5 MB/sec    1.01      2.2±0.06ms     7.5 MB/sec
formatter/numpy/globals.py                 1.04   256.3±11.23µs    11.5 MB/sec    1.00    246.9±0.78µs    12.0 MB/sec
formatter/pydantic/types.py                1.00      4.8±0.01ms     5.4 MB/sec    1.01      4.8±0.01ms     5.3 MB/sec
linter/all-rules/large/dataset.py          1.00     15.4±0.04ms     2.6 MB/sec    1.00     15.3±0.03ms     2.7 MB/sec
linter/all-rules/numpy/ctypeslib.py        1.01      3.9±0.00ms     4.2 MB/sec    1.00      3.9±0.00ms     4.3 MB/sec
linter/all-rules/numpy/globals.py          1.01    518.2±0.82µs     5.7 MB/sec    1.00    515.2±1.17µs     5.7 MB/sec
linter/all-rules/pydantic/types.py         1.00      7.0±0.01ms     3.6 MB/sec    1.00      7.0±0.01ms     3.7 MB/sec
linter/default-rules/large/dataset.py      1.01      7.9±0.02ms     5.1 MB/sec    1.00      7.9±0.02ms     5.2 MB/sec
linter/default-rules/numpy/ctypeslib.py    1.01   1687.6±7.22µs     9.9 MB/sec    1.00   1676.1±4.23µs     9.9 MB/sec
linter/default-rules/numpy/globals.py      1.00    185.1±0.35µs    15.9 MB/sec    1.00    184.5±0.32µs    16.0 MB/sec
linter/default-rules/pydantic/types.py     1.01      3.6±0.03ms     7.1 MB/sec    1.00      3.6±0.02ms     7.2 MB/sec

Windows

group                                      main                                   pr
-----                                      ----                                   --
formatter/large/dataset.py                 1.00     11.4±0.33ms     3.6 MB/sec    1.08     12.4±0.27ms     3.3 MB/sec
formatter/numpy/ctypeslib.py               1.00      2.2±0.05ms     7.4 MB/sec    1.07      2.4±0.04ms     6.9 MB/sec
formatter/numpy/globals.py                 1.00    251.0±7.05µs    11.8 MB/sec    1.04    261.4±7.59µs    11.3 MB/sec
formatter/pydantic/types.py                1.00      4.8±0.08ms     5.3 MB/sec    1.11      5.4±0.08ms     4.8 MB/sec
linter/all-rules/large/dataset.py          1.00     16.2±0.33ms     2.5 MB/sec    1.00     16.2±0.36ms     2.5 MB/sec
linter/all-rules/numpy/ctypeslib.py        1.01      4.3±0.09ms     3.8 MB/sec    1.00      4.3±0.07ms     3.9 MB/sec
linter/all-rules/numpy/globals.py          1.01   505.4±10.55µs     5.8 MB/sec    1.00    499.1±9.31µs     5.9 MB/sec
linter/all-rules/pydantic/types.py         1.02      7.5±0.21ms     3.4 MB/sec    1.00      7.4±0.17ms     3.5 MB/sec
linter/default-rules/large/dataset.py      1.00      8.3±0.16ms     4.9 MB/sec    1.01      8.4±0.17ms     4.9 MB/sec
linter/default-rules/numpy/ctypeslib.py    1.00  1714.4±21.75µs     9.7 MB/sec    1.02  1741.5±29.81µs     9.6 MB/sec
linter/default-rules/numpy/globals.py      1.00    191.4±3.44µs    15.4 MB/sec    1.02    194.9±5.02µs    15.1 MB/sec
linter/default-rules/pydantic/types.py     1.00      3.7±0.06ms     6.9 MB/sec    1.01      3.7±0.09ms     6.8 MB/sec

crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.py

crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.pyi

zanieb

Welcome and thanks for contributing!

This seems like a good candidate for a suggested or automatic fix if your up for it :)

crates/ruff/src/rules/flake8_pyi/rules/simple_defaults.rs

LaBatata101 · 2023-07-18T00:07:04Z

Welcome and thanks for contributing!

This seems like a good candidate for a suggested or automatic fix if your up for it :)

I'll try to add the automatic fix. Do you have any examples for this?

zanieb · 2023-07-18T00:09:33Z

@LaBatata101 here's an example that changes one type annotation to another https://github.com/astral-sh/ruff/pull/4695/files#diff-f72967b46be9c2c0fed6dc2bf98259327c03cc36dd28839e72cc106a60f552dbR83-R91

crates/ruff/resources/test/fixtures/flake8_pyi/PYI026.pyi

crates/ruff/src/rules/flake8_pyi/rules/simple_defaults.rs

- fix a bug in `is_valid_pep_604_union` where it was returning `true` when only receiving an `Expr::Name`, `Expr::Subscript`, `Expr::Attribute` or `Expr::Constant(ast::ExprConstant {value: Constant::None, ..})` - don't run rule for multiple targets, e.g., `x = y = 1` - change the verification for when the rule should run to match the flake8-pyi implementation - implement autofix

charliermarsh · 2023-07-20T01:34:23Z

crates/ruff/src/rules/flake8_pyi/rules/simple_defaults.rs

+
+    if !is_annotatable_type_alias(value, checker.semantic()) {
+        return;
+    }


I reordered these operations from least- to most-expensive.

charliermarsh · 2023-07-20T01:34:44Z

crates/ruff/src/rules/flake8_pyi/rules/simple_defaults.rs

@@ -523,3 +599,40 @@ pub(crate) fn unassigned_special_variable_in_stub(
        stmt.range(),
    ));
 }
+
+/// PIY026
+pub(crate) fn type_alias_without_annotation(checker: &mut Checker, value: &Expr, targets: &[Expr]) {


I renamed the method and rule to be a little more in-line with our conventions ("describe the bad case").

charliermarsh

Looks great -- nice work, thank you!

LaBatata101 added 2 commits July 17, 2023 19:35

add docs

eb3e654