ASYNC113 & ASYNC121 false alarm with nested sync functions (#287)

* fix async121 false alarm in asyncfunctiondef

* fix async113 as well

* add changelog entry, bump version

* fix pre-commit mypy error in test file

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

docs/changelog.rst

@@ -4,6 +4,11 @@ Changelog
 
 `CalVer, YY.month.patch <https://calver.org/>`_
 
+24.9.2
+======
+- Fix false alarm in :ref:`ASYNC113 <async113>` and :ref:`ASYNC121 <async121>` with sync functions nested inside an async function.
+
+
 24.9.1
 ======
 - Add :ref:`ASYNC121 <async121>` control-flow-in-taskgroup

flake8_async/__init__.py

@@ -38,7 +38,7 @@
 
 
 # CalVer: YY.month.patch, e.g. first release of July 2022 == "22.7.1"
-__version__ = "24.9.1"
+__version__ = "24.9.2"
 
 
 # taken from https://github.com/Zac-HD/shed

flake8_async/visitors/visitors.py

@@ -188,6 +188,11 @@ def visit_AsyncFunctionDef(self, node: ast.AsyncFunctionDef):
             node, "asynccontextmanager"
         )
 
+    def visit_FunctionDef(self, node: ast.FunctionDef):
+        self.save_state(node, "aenter")
+        # sync function should never be named __aenter__ or have @asynccontextmanager
+        self.aenter = False
+
     def visit_Yield(self, node: ast.Yield):
         self.aenter = False
 
@@ -398,10 +403,12 @@ def visit_Return(self, node: ast.Return) -> None:
             if unsafe_cm in self.unsafe_stack:
                 self.error(node, "return", unsafe_cm)
 
-    def visit_FunctionDef(self, node: ast.FunctionDef):
+    def visit_FunctionDef(self, node: ast.FunctionDef | ast.AsyncFunctionDef):
         self.save_state(node, "unsafe_stack", copy=True)
         self.unsafe_stack = []
 
+    visit_AsyncFunctionDef = visit_FunctionDef
+
 
 @error_class_cst
 class Visitor300(Flake8AsyncVisitor_cst):

tests/eval_files/async113.py

@@ -105,3 +105,13 @@ async def __aenter__(self):
     async def __aexit__(self, *args):
         assert self.moo is not None
         await self.nursery_manager.__aexit__(*args)
+
+
+@asynccontextmanager
+async def foo_nested_sync_def():
+    with trio.open_nursery() as bar:
+
+        def non_async_func():
+            bar.start_soon(trio.run_process)
+
+        yield

tests/eval_files/async121.py

@@ -30,6 +30,9 @@ async def foo_return_nested():
         def bar():
             return  # safe
 
+        async def bar():
+            return  # safe
+
 
 async def foo_while_safe():
     async with trio.open_nursery():