feat: add check for async context managers used with regular with

doc/data/messages/a/async-context-manager-with-regular-with/bad.py

@@ -0,0 +1,10 @@
+from contextlib import asynccontextmanager
+
+
+@asynccontextmanager
+async def async_context():
+    yield
+
+
+with async_context():  # [async-context-manager-with-regular-with]
+    print("This will cause an error at runtime")

doc/data/messages/a/async-context-manager-with-regular-with/good.py

@@ -0,0 +1,12 @@
+import asyncio
+from contextlib import asynccontextmanager
+
+
+@asynccontextmanager
+async def async_context():
+    yield
+
+
+async def main():
+    async with async_context():
+        print("This works correctly")

doc/data/messages/a/async-context-manager-with-regular-with/related.rst

@@ -0,0 +1,2 @@
+- `PEP 492 - Coroutines with async and await syntax <https://peps.python.org/pep-0492/>`_
+- `contextlib.asynccontextmanager <https://docs.python.org/3/library/contextlib.html#contextlib.asynccontextmanager>`_

doc/user_guide/checkers/features.rst

@@ -29,6 +29,9 @@ Async checker Messages
   Used when an async context manager is used with an object that does not
   implement the async context management protocol. This message can't be
   emitted when using Python < 3.5.
+:async-context-manager-with-regular-with (E1145): *Context manager '%s' is async and should be used with 'async with'.*
+  Used when an async context manager is used with a regular 'with' statement
+  instead of 'async with'.
 
 
 Bad-Chained-Comparison checker

doc/user_guide/messages/messages_overview.rst

@@ -53,6 +53,7 @@ All messages in the error category:
    error/assigning-non-slot
    error/assignment-from-no-return
    error/assignment-from-none
+   error/async-context-manager-with-regular-with
    error/await-outside-async
    error/bad-configuration-section
    error/bad-except-order

doc/whatsnew/fragments/10999.new_check

@@ -0,0 +1,3 @@
+Add new check ``async-context-manager-with-regular-with`` to detect async context managers used with regular ``with`` statements instead of ``async with``.
+
+Refs #10999

pylint/checkers/typecheck.py

@@ -299,6 +299,12 @@ def _similar_names(
         "Used when an instance in a with statement doesn't implement "
         "the context manager protocol(__enter__/__exit__).",
     ),
+    "E1145": (
+        "Context manager '%s' is async and should be used with 'async with'.",
+        "async-context-manager-with-regular-with",
+        "Used when an async context manager is used with a regular 'with' statement "
+        "instead of 'async with'.",
+    ),
     "E1130": (
         "%s",
         "invalid-unary-operand-type",
@@ -1872,7 +1878,9 @@ def _check_invalid_slice_index(self, node: nodes.Slice) -> None:
         if invalid_slice_step:
             self.add_message("invalid-slice-step", node=node.step, confidence=HIGH)
 
-    @only_required_for_messages("not-context-manager")
+    @only_required_for_messages(
+        "not-context-manager", "async-context-manager-with-regular-with"
+    )
     def visit_with(self, node: nodes.With) -> None:
         for ctx_mgr, _ in node.items:
             context = astroid.context.InferenceContext()
@@ -1886,6 +1894,17 @@ def visit_with(self, node: nodes.With) -> None:
                         inferred.parent, self.linter.config.contextmanager_decorators
                     ):
                         continue
+                    # Check if it's an AsyncGenerator decorated with asynccontextmanager
+                    if isinstance(inferred, astroid.bases.AsyncGenerator):
+                        async_decorators = ["contextlib.asynccontextmanager"]
+                        if decorated_with(inferred.parent, async_decorators):
+                            self.add_message(
+                                "async-context-manager-with-regular-with",
+                                node=node,
+                                args=(inferred.parent.name,),
+                                confidence=INFERENCE,
+                            )
+                            continue
                     # If the parent of the generator is not the context manager itself,
                     # that means that it could have been returned from another
                     # function which was the real context manager.

tests/functional/a/async_context_manager_with_regular_with.py

@@ -0,0 +1,13 @@
+# pylint: disable=missing-function-docstring
+"""Test async context manager used with regular 'with'."""
+
+from contextlib import asynccontextmanager
+
+
+@asynccontextmanager
+async def async_cm():
+    yield
+
+
+with async_cm():  # [async-context-manager-with-regular-with]
+    pass

tests/functional/a/async_context_manager_with_regular_with.txt

@@ -0,0 +1 @@
+async-context-manager-with-regular-with:12:0:13:8::Context manager 'async_cm' is async and should be used with 'async with'.:INFERENCE