Fixed current_effective_deadline() for shielded cancellation scopes

anyio/_backends/asyncio.py

@@ -294,7 +294,10 @@ async def current_effective_deadline():
     cancel_scope = _task_states[current_task()].cancel_scope
     while cancel_scope:
         deadline = min(deadline, cancel_scope.deadline)
-        cancel_scope = cancel_scope._parent_scope
+        if cancel_scope.shield:
+            break
+        else:
+            cancel_scope = cancel_scope._parent_scope
 
     return deadline
 

anyio/_backends/curio.py

@@ -187,7 +187,10 @@ async def current_effective_deadline():
     cancel_scope = _task_states[await curio.current_task()].cancel_scope
     while cancel_scope:
         deadline = min(deadline, cancel_scope.deadline)
-        cancel_scope = cancel_scope._parent_scope
+        if cancel_scope.shield:
+            break
+        else:
+            cancel_scope = cancel_scope._parent_scope
 
     return deadline
 

docs/versionhistory.rst

@@ -7,6 +7,8 @@ This library adheres to `Semantic Versioning <http://semver.org/>`_.
 
 - Fixed some corner cases of cancellation where behavior on asyncio and curio did not match with
   that of trio. Thanks to Joshua Oreman for help with this.
+- Fixed ``current_effective_deadline()`` not taking shielded cancellation scopes into account on
+  asyncio and curio
 - Added the ``current_time()`` function
 
 **1.0.0rc1**

tests/test_taskgroups.py

@@ -4,7 +4,7 @@
 
 from anyio import (
     create_task_group, sleep, move_on_after, fail_after, open_cancel_scope, wait_all_tasks_blocked,
-    current_effective_deadline)
+    current_effective_deadline, current_time)
 from anyio._backends import asyncio
 from anyio.exceptions import ExceptionGroup
 
@@ -393,3 +393,11 @@ async def parent(tg):
     async with create_task_group() as tg:
         await tg.spawn(parent, tg)
         await tg.cancel_scope.cancel()
+
+
+@pytest.mark.anyio
+async def test_shielded_deadline():
+    async with move_on_after(10):
+        async with open_cancel_scope(shield=True):
+            async with move_on_after(1000):
+                assert await current_effective_deadline() - await current_time() > 900