Issue #10332: multiprocessing: fix a race condition when a Pool is closed
before all tasks have completed.
diff --git a/Lib/multiprocessing/pool.py b/Lib/multiprocessing/pool.py
index c66876a..bcbf7e3 100644
--- a/Lib/multiprocessing/pool.py
+++ b/Lib/multiprocessing/pool.py
@@ -294,7 +294,11 @@
@staticmethod
def _handle_workers(pool):
- while pool._worker_handler._state == RUN and pool._state == RUN:
+ thread = threading.current_thread()
+
+ # Keep maintaining workers until the cache gets drained, unless the pool
+ # is terminated.
+ while thread._state == RUN or (pool._cache and thread._state != TERMINATE):
pool._maintain_pool()
time.sleep(0.1)
# send sentinel to stop workers