Changing the default dedupe statuses behavior

src/Client/Core/DurableTaskClient.cs

@@ -73,10 +73,11 @@
     /// <remarks>
     /// <para>All orchestrations must have a unique instance ID. You can provide an instance ID using the
     /// <paramref name="options"/> parameter or you can omit this and a random instance ID will be
-    /// generated for you automatically. If an orchestration with the specified instance ID already exists and is in a
-    /// non-terminal state (Pending, Running, etc.), then this operation may fail silently. However, if an orchestration
-    /// instance with this ID already exists in a terminal state (Completed, Terminated, Failed, etc.) then the instance
-    /// may be recreated automatically, depending on the configuration of the backend instance store.
+    /// generated for you automatically. If an orchestration with the specified instance ID already exists and its status
+    /// is not in the <see cref="StartOrchestrationOptions.DedupeStatuses"/> field of <paramref name="options"/>, then
+    /// a new orchestration may be recreated automatically, depending on the configuration of the backend instance store.
+    /// If the existing orchestration is in a non-terminal state (Pending, Running, etc.), then the orchestration will first
+    /// be terminated before the new orchestration is created.
     /// </para><para>
     /// Orchestration instances started with this method will be created in the
     /// <see cref="OrchestrationRuntimeStatus.Pending"/> state and will transition to the
@@ -98,8 +99,9 @@
     /// </param>
     /// <param name="options">The options to start the new orchestration with.</param>
     /// <param name="cancellation">
-    /// The cancellation token. This only cancels enqueueing the new orchestration to the backend. Does not cancel the
-    /// orchestration once enqueued.
+    /// The cancellation token. This only cancels enqueueing the new orchestration to the backend, or waiting for the
+    /// termination of an existing non-terminal instance if its status is not in
+    /// <see cref="StartOrchestrationOptions.DedupeStatuses"/>. Does not cancel the orchestration once enqueued.
     /// </param>
     /// <returns>
     /// A task that completes when the orchestration instance is successfully scheduled. The value of this task is
@@ -529,7 +531,7 @@
         throw new NotSupportedException(
             $"{this.GetType()} does not support listing orchestration instance IDs filtered by completed time.");
     }
 
     // TODO: Create task hub
 
     // TODO: Delete task hub
@@ -539,3 +541,3 @@
     /// </summary>
     /// <returns>A <see cref="ValueTask"/> that completes when the disposal completes.</returns>
     public abstract ValueTask DisposeAsync();

src/Client/Grpc/GrpcDurableTaskClient.cs

@@ -124,12 +124,9 @@ public override async Task<string> ScheduleNewOrchestrationInstanceAsync(
         }
 
         // Set orchestration ID reuse policy for deduplication support
-        // Note: This requires the protobuf to support OrchestrationIdReusePolicy field
-        // If the protobuf doesn't support it yet, this will need to be updated when the protobuf is updated
-        if (options?.DedupeStatuses != null && options.DedupeStatuses.Count > 0)
-        {
-            // Parse and validate all status strings to enum first
-            ImmutableHashSet<OrchestrationRuntimeStatus> dedupeStatuses = options.DedupeStatuses
+        ImmutableHashSet<OrchestrationRuntimeStatus> dedupeStatuses = options?.DedupeStatuses is null
+            ? []
+            : [.. options.DedupeStatuses
                 .Select(s =>
                 {
                     if (!System.Enum.TryParse<OrchestrationRuntimeStatus>(s, ignoreCase: true, out OrchestrationRuntimeStatus status))
@@ -139,17 +136,11 @@ public override async Task<string> ScheduleNewOrchestrationInstanceAsync(
                     }
 
                     return status;
-                }).ToImmutableHashSet();
-
-            // Convert dedupe statuses to protobuf statuses and create reuse policy
-            IEnumerable<P.OrchestrationStatus> dedupeStatusesProto = dedupeStatuses.Select(s => s.ToGrpcStatus());
-            P.OrchestrationIdReusePolicy? policy = ProtoUtils.ConvertDedupeStatusesToReusePolicy(dedupeStatusesProto);
+                })];
 
-            if (policy != null)
-            {
-                request.OrchestrationIdReusePolicy = policy;
-            }
-        }
+        // Convert dedupe statuses to protobuf statuses and create reuse policy
+        IEnumerable<P.OrchestrationStatus> dedupeStatusesProto = dedupeStatuses.Select(s => s.ToGrpcStatus());
+        request.OrchestrationIdReusePolicy = ProtoUtils.ConvertDedupeStatusesToReusePolicy(dedupeStatusesProto);
 
         using Activity? newActivity = TraceHelper.StartActivityForNewOrchestration(request);
 

src/Client/Grpc/ProtoUtils.cs

@@ -13,18 +13,22 @@ namespace Microsoft.DurableTask.Client.Grpc;
 public static class ProtoUtils
 {
     /// <summary>
-    /// Gets the terminal orchestration statuses that are commonly used for deduplication.
+    /// Gets an array of all orchestration statuses.
     /// These are the statuses that can be used in OrchestrationIdReusePolicy.
     /// </summary>
-    /// <returns>An immutable array of terminal orchestration statuses.</returns>
-    public static ImmutableArray<P.OrchestrationStatus> GetTerminalStatuses()
+    /// <returns>An immutable array of all orchestration statuses.</returns>
+    public static ImmutableArray<P.OrchestrationStatus> GetAllStatuses()
     {
-#pragma warning disable CS0618 // Type or member is obsolete - Canceled is intentionally included for compatibility
+#pragma warning disable CS0618 // Type or member is obsolete - Canceled is intentionally included for compatibility
+        // compatibility with what?
         return ImmutableArray.Create(
             P.OrchestrationStatus.Completed,
             P.OrchestrationStatus.Failed,
-            P.OrchestrationStatus.Terminated,
-            P.OrchestrationStatus.Canceled);
+            P.OrchestrationStatus.Terminated,
+            P.OrchestrationStatus.Canceled,
+            P.OrchestrationStatus.Pending,
+            P.OrchestrationStatus.Running,
+            P.OrchestrationStatus.Suspended);
 #pragma warning restore CS0618
     }
 
@@ -33,55 +37,49 @@ public static class ProtoUtils
     /// with replaceable statuses (statuses that CAN be replaced).
     /// </summary>
     /// <param name="dedupeStatuses">The orchestration statuses that should NOT be replaced. These are statuses for which an exception should be thrown if an orchestration already exists.</param>
-    /// <returns>An OrchestrationIdReusePolicy with replaceable statuses set, or null if all terminal statuses are dedupe statuses.</returns>
+    /// <returns>An OrchestrationIdReusePolicy with replaceable statuses set.</returns>
     /// <remarks>
     /// The policy uses "replaceableStatus" - these are statuses that CAN be replaced.
     /// dedupeStatuses are statuses that should NOT be replaced.
-    /// So replaceableStatus = all terminal statuses MINUS dedupeStatuses.
+    /// So replaceableStatus = all statuses MINUS dedupeStatuses.
     /// </remarks>
-    public static P.OrchestrationIdReusePolicy? ConvertDedupeStatusesToReusePolicy(
+    public static P.OrchestrationIdReusePolicy ConvertDedupeStatusesToReusePolicy(
         IEnumerable<P.OrchestrationStatus>? dedupeStatuses)
     {
-        ImmutableArray<P.OrchestrationStatus> terminalStatuses = GetTerminalStatuses();
+        ImmutableArray<P.OrchestrationStatus> statuses = GetAllStatuses();
         ImmutableHashSet<P.OrchestrationStatus> dedupeStatusSet = dedupeStatuses?.ToImmutableHashSet() ?? ImmutableHashSet<P.OrchestrationStatus>.Empty;
 
         P.OrchestrationIdReusePolicy policy = new();
 
-        // Add terminal statuses that are NOT in dedupeStatuses as replaceable
-        foreach (P.OrchestrationStatus terminalStatus in terminalStatuses.Where(status => !dedupeStatusSet.Contains(status)))
+        // Add statuses that are NOT in dedupeStatuses as replaceable
+        foreach (P.OrchestrationStatus status in statuses.Where(status => !dedupeStatusSet.Contains(status)))
         {
-            policy.ReplaceableStatus.Add(terminalStatus);
+            policy.ReplaceableStatus.Add(status);
         }
 
-        // Only return policy if we have replaceable statuses
-        return policy.ReplaceableStatus.Count > 0 ? policy : null;
+        return policy;
     }
 
     /// <summary>
     /// Converts an OrchestrationIdReusePolicy with replaceable statuses to dedupe statuses
     /// (statuses that should NOT be replaced).
     /// </summary>
     /// <param name="policy">The OrchestrationIdReusePolicy containing replaceable statuses.</param>
-    /// <returns>An array of orchestration statuses that should NOT be replaced, or null if all terminal statuses are replaceable.</returns>
+    /// <returns>An array of orchestration statuses that should NOT be replaced, or null if all statuses are replaceable.</returns>
     /// <remarks>
     /// The policy uses "replaceableStatus" - these are statuses that CAN be replaced.
     /// dedupeStatuses are statuses that should NOT be replaced (should throw exception).
-    /// So dedupeStatuses = all terminal statuses MINUS replaceableStatus.
+    /// So dedupeStatuses = all statuses MINUS replaceableStatus.
     /// </remarks>
     public static P.OrchestrationStatus[]? ConvertReusePolicyToDedupeStatuses(
-        P.OrchestrationIdReusePolicy? policy)
+        P.OrchestrationIdReusePolicy policy)
     {
-        if (policy == null || policy.ReplaceableStatus.Count == 0)
-        {
-            return null;
-        }
-
-        ImmutableArray<P.OrchestrationStatus> terminalStatuses = GetTerminalStatuses();
+        ImmutableArray<P.OrchestrationStatus> allStatuses = GetAllStatuses();
         ImmutableHashSet<P.OrchestrationStatus> replaceableStatusSet = policy.ReplaceableStatus.ToImmutableHashSet();
 
-        // Calculate dedupe statuses = terminal statuses - replaceable statuses
-        P.OrchestrationStatus[] dedupeStatuses = terminalStatuses
-            .Where(terminalStatus => !replaceableStatusSet.Contains(terminalStatus))
+        // Calculate dedupe statuses = all statuses - replaceable statuses
+        P.OrchestrationStatus[] dedupeStatuses = allStatuses
+            .Where(status => !replaceableStatusSet.Contains(status))
             .ToArray();
 
         // Only return if there are dedupe statuses

src/InProcessTestHost/Sidecar/Grpc/TaskHubGrpcServer.cs

@@ -232,7 +232,7 @@ async Task WaitForWorkItemClientConnection()
             // Convert OrchestrationIdReusePolicy to dedupeStatuses
             // The policy uses "replaceableStatus" - these are statuses that CAN be replaced
             // dedupeStatuses are statuses that should NOT be replaced (should throw exception)
-            // So dedupeStatuses = all terminal statuses MINUS replaceableStatus
+            // So dedupeStatuses = all statuses MINUS replaceableStatus
             OrchestrationStatus[]? dedupeStatuses = null;
             P.OrchestrationStatus[]? dedupeStatusesProto = ProtoUtils.ConvertReusePolicyToDedupeStatuses(request.OrchestrationIdReusePolicy);
             if (dedupeStatusesProto != null)