Drop-off fabric sensitive event when fabric is undefined (#21942)

Author: yunhanw-google

src/app/EventLogging.h

@@ -72,6 +72,8 @@ CHIP_ERROR LogEvent(const T & aEventData, EndpointId aEndpoint, EventNumber & aE
     eventOptions.mPath        = path;
     eventOptions.mPriority    = aEventData.GetPriorityLevel();
     eventOptions.mFabricIndex = aEventData.GetFabricIndex();
+    // this skips logging the event if it's fabric-scoped but no fabric association exists yet.
+    VerifyOrReturnError(eventOptions.mFabricIndex != kUndefinedFabricIndex, CHIP_NO_ERROR);
 
     //
     // Unlike attributes which have a different 'EncodeForRead' for fabric-scoped structs,

src/app/clusters/test-cluster-server/test-cluster-server.cpp

@@ -797,7 +797,7 @@ bool emberAfTestClusterClusterTestEmitTestFabricScopedEventRequestCallback(
 {
     Commands::TestEmitTestFabricScopedEventResponse::Type responseData;
     Events::TestFabricScopedEvent::Type event{ commandData.arg1 };
-
+    event.fabricIndex = commandData.arg1;
     if (CHIP_NO_ERROR != LogEvent(event, commandPath.mEndpointId, responseData.value))
     {
         emberAfSendImmediateDefaultResponse(EMBER_ZCL_STATUS_FAILURE);

src/controller/python/test/test_scripts/cluster_objects.py

@@ -331,6 +331,16 @@ async def TriggerAndWaitForEvents(cls, devCtrl, req):
         await cls._TriggerEvent(devCtrl)
         await cls._RetryForContent(request=lambda: devCtrl.ReadEvent(nodeid=NODE_ID, events=req), until=lambda res: res != 0)
 
+    @classmethod
+    @base.test_case
+    async def TestGenerateUndefinedFabricScopedEventRequests(cls, devCtrl):
+        logger.info("Running TestGenerateUndefinedFabricScopedEventRequests")
+        await devCtrl.SendCommand(nodeid=NODE_ID, endpoint=1, payload=Clusters.TestCluster.Commands.TestEmitTestFabricScopedEventRequest(arg1=0))
+        res = await devCtrl.ReadEvent(nodeid=NODE_ID, events=[
+            (1, Clusters.TestCluster.Events.TestEvent, 0),
+        ])
+        logger.info(f"return result is {res}")
+
     @classmethod
     @base.test_case
     async def TestReadEventRequests(cls, devCtrl, expectEventsNum):
@@ -557,6 +567,7 @@ async def RunTest(cls, devCtrl):
             await cls.TestWriteRequest(devCtrl)
             await cls.TestTimedRequest(devCtrl)
             await cls.TestTimedRequestTimeout(devCtrl)
+            await cls.TestGenerateUndefinedFabricScopedEventRequests(devCtrl)
         except Exception as ex:
             logger.error(
                 f"Unexpected error occurred when running tests: {ex}")