task: allow queuing a CancelFrame to cancel the task

CHANGELOG.md

@@ -15,6 +15,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed a `PipelineTask` issue that was preventing processors to be cleaned up
   after cancelling the task.
 
+- Fixed an issue where queuing a `CancelFrame` to a pipeline task would not
+  cause the task to finish. However, using `PipelineTask.cancel()` is still the
+  recommended way to cancel a task.
+
 ### Other
 
 - Updated all examples to use `task.cancel()` instead of pushing an `EndFrame`

src/pipecat/pipeline/task.py

@@ -279,7 +279,7 @@ class PipelineTask(BaseTask):
             await self._source.queue_frame(frame, FrameDirection.DOWNSTREAM)
             if isinstance(frame, EndFrame):
                 await self._wait_for_endframe()
-            running = not isinstance(frame, (StopTaskFrame, EndFrame))
+            running = not isinstance(frame, (CancelFrame, EndFrame, StopTaskFrame))
             should_cleanup = not isinstance(frame, StopTaskFrame)
             self._push_queue.task_done()
         # Cleanup only if we need to.