Expand return code values returned by TQM and strategies

This allows the PlaybookExecutor to receive more information regarding
what happened internal to the TaskQueueManager and strategy, to determine
things like whether or not the play iteration should stop.

Fixes #15523

lib/ansible/plugins/strategy/__init__.py

@@ -120,7 +120,7 @@ class StrategyBase:
     def run(self, iterator, play_context, result=True):
         # save the failed/unreachable hosts, as the run_handlers()
         # method will clear that information during its execution
-        failed_hosts      = self._tqm._failed_hosts.keys()
+        failed_hosts      = iterator.get_failed_hosts()
         unreachable_hosts = self._tqm._unreachable_hosts.keys()
 
         display.debug("running handlers")
@@ -128,18 +128,20 @@ class StrategyBase:
 
         # now update with the hosts (if any) that failed or were
         # unreachable during the handler execution phase
-        failed_hosts      = set(failed_hosts).union(self._tqm._failed_hosts.keys())
+        failed_hosts      = set(failed_hosts).union(iterator.get_failed_hosts())
         unreachable_hosts = set(unreachable_hosts).union(self._tqm._unreachable_hosts.keys())
 
         # return the appropriate code, depending on the status hosts after the run
-        if len(unreachable_hosts) > 0:
-            return 3
+        if not isinstance(result, bool) and result != self._tqm.RUN_OK:
+            return result
+        elif len(unreachable_hosts) > 0:
+            return self._tqm.RUN_UNREACHABLE_HOSTS
         elif len(failed_hosts) > 0:
-            return 2
-        elif not result:
-            return 1
+            return self._tqm.RUN_FAILED_HOSTS
+        elif isinstance(result, bool) and not result:
+            return self._tqm.RUN_ERROR
         else:
-            return 0
+            return self._tqm.RUN_OK
 
     def get_hosts_remaining(self, play):
         return [host for host in self._inventory.get_hosts(play.hosts)