Merge pull request #18456 from jhance/gil-fix

Make gil handling in completion queue more robust

src/python/grpcio/grpc/_cython/_cygrpc/completion_queue.pyx.pxi

@@ -30,19 +30,20 @@ cdef grpc_event _next(grpc_completion_queue *c_completion_queue, deadline):
   else:
     c_deadline = _timespec_from_time(deadline)
 
-  with nogil:
-    while True:
+  while True:
+    with nogil:
       c_timeout = gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), c_increment)
       if gpr_time_cmp(c_timeout, c_deadline) > 0:
         c_timeout = c_deadline
+  
       c_event = grpc_completion_queue_next(c_completion_queue, c_timeout, NULL)
+  
       if (c_event.type != GRPC_QUEUE_TIMEOUT or
           gpr_time_cmp(c_timeout, c_deadline) == 0):
         break
 
-      # Handle any signals
-      with gil:
-        cpython.PyErr_CheckSignals()
+    # Handle any signals
+    cpython.PyErr_CheckSignals()
   return c_event