Test the actual application of broadcasts.

Make the whole PR work.

Author: wxtim

cylc/flow/broadcast_mgr.py

@@ -320,11 +320,12 @@ def put_broadcast(
                                 self.broadcasts.get(point_string, {})
                                 .get(namespace, {})
                             )
-                            self.check_for_old_and_new_platform_settings(
+                            if self.bc_mixes_old_and_new_platform_settings(
                                 newconfig,
                                 namespace,
                                 coerced_setting,
-                            )
+                            ):
+                                continue
 
                             if namespace not in self.broadcasts[point_string]:
                                 self.broadcasts[point_string][namespace] = {}
@@ -355,7 +356,7 @@ def put_broadcast(
         return modified_settings, bad_options
 
     @staticmethod
-    def check_for_old_and_new_platform_settings(
+    def bc_mixes_old_and_new_platform_settings(
         task_config, namespace, coerced_setting
     ):
         """Check for combination of old ([remote]host) and new (platform)
@@ -366,8 +367,10 @@ def check_for_old_and_new_platform_settings(
             fail_if_platform_and_host_conflict(
                 task_config, namespace
             )
+            return False
         except PlatformLookupError as exc:
             LOG.error('Cannot apply broadcast:\n' + '\n    '.join(exc.args))
+            return True
 
     @staticmethod
     def _cancel_keys_in_prunes(prunes, cancel_keys):

tests/integration/test_broadcast_mgr.py

@@ -27,9 +27,8 @@ async def test_reject_valid_broadcast_is_remote_clash_with_config(
 
     https://github.com/cylc/cylc-flow/issues/6693
     """
-    conf = one_conf.copy()
-    conf.update({'runtime': {'root': {'platform': 'foo'}}})
-    wid = flow(conf)
+    one_conf.update({'runtime': {'root': {'platform': 'foo'}}})
+    wid = flow(one_conf)
     schd = scheduler(wid)
     async with start(schd):
         bc_mgr = schd.broadcast_mgr
@@ -39,6 +38,7 @@ async def test_reject_valid_broadcast_is_remote_clash_with_config(
             settings=[{'remote': {'host': 'bar'}}]
         )
         assert log_filter(contains='Cannot apply broadcast')
+        assert bc_mgr.broadcasts == {'1': {}}
 
 
 async def test_reject_valid_broadcast_is_remote_clash_with_broadcast(
@@ -67,3 +67,4 @@ async def test_reject_valid_broadcast_is_remote_clash_with_broadcast(
             settings=[{'platform': 'foo'}]
         )
         assert log_filter(contains='Cannot apply broadcast')
+        assert bc_mgr.broadcasts == {'1': {'one': {'remote': {'host': 'bar'}}}}