Followup changes to fix ruff & pyright warnings

README.md

@@ -1,3 +1,4 @@
+[![pre-commit.ci status](https://results.pre-commit.ci/badge/github/python-trio/flake8-trio/main.svg)](https://results.pre-commit.ci/latest/github/python-trio/flake8-trio/main)
 # flake8-trio
 
 A highly opinionated flake8 plugin for [Trio](https://github.com/python-trio/trio)-related problems.

flake8_trio/base.py

@@ -29,18 +29,6 @@ class Statement(NamedTuple):
     lineno: int
     col_offset: int = -1
 
-    # pyright is unhappy about defining __eq__ but not __hash__ .. which it should
-    # but it works :tm: and needs changing in a couple places to avoid it.
-    def __eq__(self, other: object) -> bool:
-        return (
-            isinstance(other, Statement)
-            and self[:2] == other[:2]
-            and (
-                self.col_offset == other.col_offset
-                or -1 in (self.col_offset, other.col_offset)
-            )
-        )
-
 
 class Error:
     def __init__(

flake8_trio/runner.py

@@ -21,7 +21,7 @@
 from .visitors.visitor_utility import NoqaHandler
 
 if TYPE_CHECKING:
-    from collections.abc import Iterable
+    from collections.abc import Iterable, Mapping
 
     from libcst import Module
 
@@ -46,7 +46,7 @@ def __init__(self, options: Options):
         super().__init__()
         self.state = SharedState(options)
 
-    def selected(self, error_codes: dict[str, str]) -> bool:
+    def selected(self, error_codes: Mapping[str, str]) -> bool:
         enabled_or_autofix = (
             self.state.options.enabled_codes | self.state.options.autofix_codes
         )

flake8_trio/visitors/flake8triovisitor.py

@@ -4,15 +4,15 @@
 
 import ast
 from abc import ABC
-from typing import TYPE_CHECKING, Any, ClassVar, Union
+from typing import TYPE_CHECKING, Any, Union
 
 import libcst as cst
 from libcst.metadata import PositionProvider
 
 from ..base import Error, Statement
 
 if TYPE_CHECKING:
-    from collections.abc import Iterable
+    from collections.abc import Iterable, Mapping
 
     from ..runner import SharedState
 
@@ -23,7 +23,7 @@
 
 class Flake8TrioVisitor(ast.NodeVisitor, ABC):
     # abstract attribute by not providing a value
-    error_codes: ClassVar[dict[str, str]]
+    error_codes: Mapping[str, str]
 
     def __init__(self, shared_state: SharedState):
         super().__init__()
@@ -158,7 +158,7 @@ def add_library(self, name: str) -> None:
 
 class Flake8TrioVisitor_cst(cst.CSTTransformer, ABC):
     # abstract attribute by not providing a value
-    error_codes: dict[str, str]
+    error_codes: Mapping[str, str]
     METADATA_DEPENDENCIES = (PositionProvider,)
 
     def __init__(self, shared_state: SharedState):

flake8_trio/visitors/visitor91x.py

@@ -26,9 +26,10 @@
 )
 
 if TYPE_CHECKING:
-    from collections.abc import Sequence
+    from collections.abc import Mapping, Sequence
 
 
+# Statement injected at the start of loops to track missed checkpoints.
 ARTIFICIAL_STATEMENT = Statement("artificial", -1)
 
 
@@ -226,7 +227,7 @@ def leave_Yield(
 @error_class_cst
 @disabled_by_default
 class Visitor91X(Flake8TrioVisitor_cst, CommonVisitors):
-    error_codes = {
+    error_codes: Mapping[str, str] = {
         "TRIO910": (
             "{0} from async function with no guaranteed checkpoint or exception "
             "since function definition on line {1.lineno}."
@@ -591,10 +592,7 @@ def visit_While_body(self, node: cst.For | cst.While):
         if getattr(node, "asynchronous", None):
             self.uncheckpointed_statements = set()
         else:
-            # pyright correctly dislikes Statement defining __eq__ but not __hash__
-            # but it works:tm:, and changing it touches on various bits of code, so
-            # leaving it for another time.
-            self.uncheckpointed_statements = {ARTIFICIAL_STATEMENT}  # pyright: ignore
+            self.uncheckpointed_statements = {ARTIFICIAL_STATEMENT}
 
         self.loop_state.uncheckpointed_before_continue = set()
         self.loop_state.uncheckpointed_before_break = set()

pyproject.toml

@@ -95,10 +95,8 @@ ignore = [
   'TRY003',  # Avoid specifying long messages outside the exception class
   'B904',  # Use `raise from` to specify exception cause
   'TRY201',  # Use `raise` without specifying exception name
-  'FIX002',  # line contains #TODO
-  'RUF012'  # Mutable class attribute should be annotated with `typing.ClassVar`
+  'FIX002'  # line contains #TODO
 ]
-# RUF012 occurs in 25 places ... I'm not going to fix that unless type checkers also complain
 select = ["ALL"]
 
 [tool.ruff.lint.per-file-ignores]

tests/test_flake8_trio.py

@@ -50,6 +50,22 @@
 class ParseError(Exception): ...
 
 
+class ColumnAgnosticStatement(Statement):
+    def __eq__(self, other: object) -> bool:
+        assert isinstance(other, Statement)
+        return (
+            self.name == other.name
+            and self.lineno == other.lineno
+            and (
+                self.col_offset == other.col_offset
+                or -1 in (self.col_offset, other.col_offset)
+            )
+        )
+
+    def __hash__(self) -> int:
+        raise NotImplementedError
+
+
 # check for presence of _pyXX, skip if version is later, and prune parameter
 def check_version(test: str):
     python_version = re.search(r"(?<=_PY)\d*", test)
@@ -332,8 +348,8 @@ def _parse_eval_file(test: str, content: str) -> tuple[list[Error], list[str], s
                         {
                             "lineno": lineno,
                             "line": lineno,
-                            "Statement": Statement,
-                            "Stmt": Statement,
+                            "Statement": ColumnAgnosticStatement,
+                            "Stmt": ColumnAgnosticStatement,
                         },
                     )
                 except NameError: