fix crash. Make identifier_to_string less footgunny. (#323)

* fix crash. Make identifier_to_string less footgunny.

* add changelog & bump version. Fix incorrect changelog placement.

docs/changelog.rst

@@ -4,20 +4,24 @@ Changelog
 
 `CalVer, YY.month.patch <https://calver.org/>`_
 
+24.11.2
+=======
+- Fix crash in ``Visitor91x`` on ``async with a().b():``.
+
 24.11.1
 =======
 - :ref:`ASYNC100 <async100>` now ignores :func:`trio.open_nursery` and :func:`anyio.create_task_group`
   as cancellation sources, because they are :ref:`schedule points <schedule_points>` but not
   :ref:`cancellation points <cancel_points>`.
+- :ref:`ASYNC101 <async101>` and :ref:`ASYNC119 <async119>` are now silenced for decorators in :ref:`transform-async-generator-decorators`.
 
 24.10.2
 =======
-- :ref:`ASYNC101 <async101>` and :ref:`ASYNC119 <async119>` are now silenced for decorators in :ref:`transform-async-generator-decorators`
 - :ref:`ASYNC102 <async102>` now also warns about ``await()`` inside ``__aexit__``.
 
 24.10.1
 =======
-- Add :ref:`ASYNC123 <async123>` bad-exception-group-flattening
+- Add :ref:`ASYNC123 <async123>` bad-exception-group-flattening.
 
 24.9.5
 ======

flake8_async/__init__.py

@@ -38,7 +38,7 @@
 
 
 # CalVer: YY.month.patch, e.g. first release of July 2022 == "22.7.1"
-__version__ = "24.11.1"
+__version__ = "24.11.2"
 
 
 # taken from https://github.com/Zac-HD/shed

flake8_async/visitors/helpers.py

@@ -337,15 +337,20 @@ def build_cst_matcher(attr: str) -> m.BaseExpression:
     return m.Attribute(value=build_cst_matcher(body), attr=m.Name(value=tail))
 
 
-def identifier_to_string(attr: cst.Name | cst.Attribute) -> str | None:
-    if isinstance(attr, cst.Name):
-        return attr.value
-    if not isinstance(attr.value, (cst.Attribute, cst.Name)):
-        return None
-    lhs = identifier_to_string(attr.value)
-    if lhs is None:
-        return None
-    return lhs + "." + attr.attr.value
+def identifier_to_string(node: cst.CSTNode) -> str | None:
+    """Convert a simple identifier to a string.
+
+    If the node is composed of anything but cst.Name + cst.Attribute it returns None.
+    """
+    if isinstance(node, cst.Name):
+        return node.value
+    if (
+        isinstance(node, cst.Attribute)
+        and (lhs := identifier_to_string(node.value)) is not None
+    ):
+        return lhs + "." + node.attr.value
+
+    return None
 
 
 def with_has_call(

flake8_async/visitors/visitor91x.py

@@ -501,17 +501,16 @@ def _checkpoint_with(self, node: cst.With):
         """
         if getattr(node, "asynchronous", None):
             for item in node.items:
-                if not isinstance(item.item, cst.Call) or not isinstance(
-                    item.item.func, (cst.Attribute, cst.Name)
+                if not (
+                    isinstance(item.item, cst.Call)
+                    and identifier_to_string(item.item.func)
+                    in (
+                        "trio.open_nursery",
+                        "anyio.create_task_group",
+                    )
                 ):
                     self.checkpoint()
                     break
-
-                func = identifier_to_string(item.item.func)
-                assert func is not None
-                if func not in ("trio.open_nursery", "anyio.create_task_group"):
-                    self.checkpoint()
-                    break
             else:
                 self.uncheckpointed_statements = set()
 

flake8_async/visitors/visitors.py

@@ -5,8 +5,6 @@
 import ast
 from typing import TYPE_CHECKING, Any, cast
 
-import libcst as cst
-
 from .flake8asyncvisitor import Flake8AsyncVisitor, Flake8AsyncVisitor_cst
 from .helpers import (
     disabled_by_default,
@@ -20,6 +18,8 @@
 if TYPE_CHECKING:
     from collections.abc import Mapping
 
+    import libcst as cst
+
 LIBRARIES = ("trio", "anyio", "asyncio")
 
 
@@ -460,8 +460,7 @@ def visit_CompIf(self, node: cst.CSTNode):
 
     def visit_Call(self, node: cst.Call):
         if (
-            isinstance(node.func, (cst.Name, cst.Attribute))
-            and identifier_to_string(node.func) == "asyncio.create_task"
+            identifier_to_string(node.func) == "asyncio.create_task"
             and not self.safe_to_create_task
         ):
             self.error(node)

tests/autofix_files/async100.py

@@ -141,3 +141,8 @@ async def nursery_no_cancel_point():
 async def dont_crash_on_non_name_or_attr_call():
     async with contextlib.asynccontextmanager(agen_fn)():
         ...
+
+
+async def another_weird_with_call():
+    async with a().b():
+        ...

tests/eval_files/async100.py

@@ -141,3 +141,8 @@ async def nursery_no_cancel_point():
 async def dont_crash_on_non_name_or_attr_call():
     async with contextlib.asynccontextmanager(agen_fn)():
         ...
+
+
+async def another_weird_with_call():
+    async with a().b():
+        ...