address PR feedback

src/DurableTask.Netherite/OrchestrationService/OrchestrationMessageBatch.cs

@@ -118,22 +118,23 @@ namespace DurableTask.Netherite
                 this.workItem.EventCount = historyState.History?.Count ?? 0;
             }
 
-            if (!this.IsExecutableInstance(this.workItem, out var reason, out bool traceWarningEvenForTimers))
+            if (!this.IsExecutableInstance(this.workItem, out string reason, out bool isNormalSituationForTimerFired))
             {
                 // this instance cannot be executed, so we are discarding the messages
                 for (int i = 0; i < this.workItem.MessageBatch.MessagesToProcess.Count; i++)
                 {
                     TaskMessage message = this.workItem.MessageBatch.MessagesToProcess[i];
 
-                    // since this can happen by design for canceled timers, we are not always creating warnings
-                    if (traceWarningEvenForTimers || ! (message.Event is TimerFiredEvent))
+                    if (isNormalSituationForTimerFired && message.Event is TimerFiredEvent)
                     {
-                        partition.WorkItemTraceHelper.TraceTaskMessageDiscarded(
+                        continue; // do not trace a warning since it is a common situation
+                    }
+
+                    partition.WorkItemTraceHelper.TraceTaskMessageDiscarded(
                             this.PartitionId,
                             message,
                             this.workItem.MessageBatch.MessagesToProcessOrigin[i],
                             reason);
-                    }
                 }
 
                 // we issue a batch processed event which will remove the messages without updating the instance state
@@ -168,16 +169,16 @@ namespace DurableTask.Netherite
             this.workItem.Partition.EnqueueOrchestrationWorkItem(this.workItem);
         }
 
-        bool IsExecutableInstance(TaskOrchestrationWorkItem workItem, out string message, out bool traceWarningEvenForTimers)
+        bool IsExecutableInstance(TaskOrchestrationWorkItem workItem, out string message, out bool isNormalSituationForTimerFired)
         {
             message = default;
-            traceWarningEvenForTimers = default;
 
             if (workItem.OrchestrationRuntimeState.ExecutionStartedEvent == null
                 && !this.MessagesToProcess.Any(msg => msg.Event is ExecutionStartedEvent))
             {
                 if (DurableTask.Core.Common.Entities.AutoStart(this.InstanceId, this.MessagesToProcess))
                 {
+                    isNormalSituationForTimerFired = default;
                     return true;
                 }
                 else
@@ -185,17 +186,17 @@ namespace DurableTask.Netherite
                     if (DurableTask.Core.Common.Entities.IsEntityInstance(this.InstanceId))
                     {
                         message = "Instance is an entity that cannot process this type of message";
-                        traceWarningEvenForTimers = true;
+                        isNormalSituationForTimerFired = false;
                     }
                     else if (workItem.OrchestrationRuntimeState.Events.Count == 0)
                     {
                         message = "Instance does not exist (it may have been purged)";
-                        traceWarningEvenForTimers = false;
+                        isNormalSituationForTimerFired = true;
                     }
                     else
                     {
                         message = $"Instance has an invalid history ({workItem.OrchestrationRuntimeState.Events} events)";
-                        traceWarningEvenForTimers = true;
+                        isNormalSituationForTimerFired = false;
                     }
                     return false;                   
                 }
@@ -206,10 +207,11 @@ namespace DurableTask.Netherite
                 workItem.OrchestrationRuntimeState.OrchestrationStatus != OrchestrationStatus.Pending)
             {
                 message = $"Instance is {workItem.OrchestrationRuntimeState.OrchestrationStatus}";
-                traceWarningEvenForTimers = false;
+                isNormalSituationForTimerFired = true;
                 return false;
             }
 
+            isNormalSituationForTimerFired = default;
             return true;
         }
     }