async110 now also warns if looping .lowlevel.checkpoint()

CHANGELOG.md

@@ -1,6 +1,9 @@
 # Changelog
 *[CalVer, YY.month.patch](https://calver.org/)*
 
+## 24.3.4
+- ASYNC110 (don't loop sleep) now also warns if looping `[trio/anyio].lowlevel.checkpoint()`
+
 ## 24.3.3
 - Add ASYNC251: `time.sleep()` in async method.
 

flake8_async/__init__.py

@@ -37,7 +37,7 @@
 
 
 # CalVer: YY.month.patch, e.g. first release of July 2022 == "22.7.1"
-__version__ = "24.3.3"
+__version__ = "24.3.4"
 
 
 # taken from https://github.com/Zac-HD/shed

flake8_async/visitors/visitors.py

@@ -65,7 +65,19 @@ def visit_While(self, node: ast.While):
             len(node.body) == 1
             and isinstance(node.body[0], ast.Expr)
             and isinstance(node.body[0].value, ast.Await)
-            and get_matching_call(node.body[0].value.value, "sleep", "sleep_until")
+            and (
+                get_matching_call(node.body[0].value.value, "sleep", "sleep_until")
+                or (
+                    # get_matching_call doesn't (currently) support checking for trio.x.y
+                    isinstance(call := node.body[0].value.value, ast.Call)
+                    and isinstance(call.func, ast.Attribute)
+                    and call.func.attr == "checkpoint"
+                    and isinstance(call.func.value, ast.Attribute)
+                    and call.func.value.attr == "lowlevel"
+                    and isinstance(call.func.value.value, ast.Name)
+                    and call.func.value.value.id in ("trio", "anyio")
+                )
+            )
         ):
             self.error(node, self.library_str)
 

tests/eval_files/async110.py

@@ -69,3 +69,8 @@ async def blah():
 
     while await trio.sleep():
         ...
+
+    # also error when looping .lowlevel.checkpoint, which is equivalent to .sleep(0)
+    # see https://github.com/python-trio/flake8-async/issues/201
+    while ...:  # ASYNC110: 4, "trio"
+        await trio.lowlevel.checkpoint()