Revert "Propagate hub region header to hedged requests via shared state"

This reverts commit dd41d00.

Author: aavasthy

Microsoft.Azure.Cosmos/src/ClientRetryPolicy.cs

@@ -228,21 +228,11 @@ public void OnBeforeSendRequest(DocumentServiceRequest request)
                 }
             }
 #if !INTERNAL
-            // If previous attempt failed with 404/1002, add the hub-region-processing-only header to all subsequent retry attempts.
-            // Also check the shared state for hedged requests — another request in the same operation
-            // may have already discovered that the hub header is needed.
-            bool shouldAddHeader = this.addHubRegionProcessingOnlyHeader;
-            if (!shouldAddHeader
-                && request.Properties != null
-                && request.Properties.TryGetValue(HubRegionProcessingState.RequestPropertyKey, out object sharedState))
-            {
-                shouldAddHeader = ((HubRegionProcessingState)sharedState).ShouldAddHubRegionProcessingOnlyHeader;
-            }
-
-            if (shouldAddHeader)
-            {
-                request.Headers[HttpConstants.HttpHeaders.ShouldProcessOnlyInHubRegion] = bool.TrueString;
-            }
+            // If previous attempt failed with 404/1002, add the hub-region-processing-only header to all subsequent retry attempts
+            if (this.addHubRegionProcessingOnlyHeader)
+            {
+                request.Headers[HttpConstants.HttpHeaders.ShouldProcessOnlyInHubRegion] = bool.TrueString;
+            }
 #endif
             // Resolve the endpoint for the request and pin the resolution to the resolved endpoint
             // This enables marking the endpoint unavailability on endpoint failover/unreachability
@@ -466,15 +456,6 @@ private ShouldRetryResult ShouldRetryOnSessionNotAvailable(DocumentServiceReques
                     if (this.sessionTokenRetryCount >= MaxSessionTokenRetryCount)
                     {
                         this.addHubRegionProcessingOnlyHeader = true;
-
-                        // Signal shared state so hedged requests in the same operation
-                        // can immediately include the hub header without their own 2x 404/1002 cycle.
-                        if (this.documentServiceRequest?.Properties != null
-                            && this.documentServiceRequest.Properties.TryGetValue(
-                                HubRegionProcessingState.RequestPropertyKey, out object sharedState))
-                        {
-                            ((HubRegionProcessingState)sharedState).ShouldAddHubRegionProcessingOnlyHeader = true;
-                        }
                     }
 
                     if (this.sessionTokenRetryCount > MaxSessionTokenRetryCount)

Microsoft.Azure.Cosmos/src/Routing/AvailabilityStrategy/CrossRegionHedgingAvailabilityStrategy.cs

@@ -138,17 +138,7 @@ internal override async Task<ResponseMessage> ExecuteAvailabilityStrategyAsync(
             {
                 return await sender(request, applicationProvidedCancellationToken);
             }
-
-#if !INTERNAL
-            // Inject shared hub region state so all hedged clones can coordinate.
-            // When one clone's retry discovers hub header is needed (after 2x 404/1002),
-            // all subsequent clones inherit the header immediately via this shared reference.
-            if (!request.Properties.ContainsKey(HubRegionProcessingState.RequestPropertyKey))
-            {
-                request.Properties[HubRegionProcessingState.RequestPropertyKey] = new HubRegionProcessingState();
-            }
-#endif
-
+            
             ITrace trace = request.Trace;
 
             using (CancellationTokenSource hedgeRequestsCancellationTokenSource = 

Microsoft.Azure.Cosmos/src/Routing/AvailabilityStrategy/HubRegionProcessingState.cs

@@ -673,92 +673,6 @@ public async Task ClientRetryPolicy_HubRegionHeader_PersistsThroughRetriableErro
             Assert.AreEqual(bool.TrueString, headerValues[0], "Hub region header value should remain 'True'.");
         }
 
-        /// <summary>
-        /// Validates that the shared <see cref="HubRegionProcessingState"/> propagates the hub region
-        /// header to a second (hedged) ClientRetryPolicy that shares the same Properties dictionary.
-        /// Scenario:
-        ///   1. Primary request hits 2x 404/1002 → sets shared state to true.
-        ///   2. Hedged request (using the same Properties) checks OnBeforeSendRequest on its FIRST attempt.
-        ///   3. Asserts the hub header is present immediately without the hedge needing its own 404/1002 cycle.
-        /// </summary>
-        [TestMethod]
-        public async Task ClientRetryPolicy_HubRegionHeader_PropagatedToHedgedRequest_ViaSharedState()
-        {
-            const bool enableEndpointDiscovery = true;
-
-            using GlobalEndpointManager endpointManager = this.Initialize(
-                useMultipleWriteLocations: false,
-                enableEndpointDiscovery: enableEndpointDiscovery,
-                isPreferredLocationsListEmpty: false,
-                enforceSingleMasterSingleWriteLocation: true);
-
-            // Create shared properties (simulates what CrossRegionHedgingAvailabilityStrategy does)
-            Dictionary<string, object> sharedProperties = new Dictionary<string, object>
-            {
-                [HubRegionProcessingState.RequestPropertyKey] = new HubRegionProcessingState()
-            };
-
-            // ---- PRIMARY REQUEST: goes through 2x 404/1002 discovery ----
-            ClientRetryPolicy primaryRetryPolicy = new ClientRetryPolicy(
-                endpointManager,
-                this.partitionKeyRangeLocationCache,
-                new RetryOptions(),
-                enableEndpointDiscovery,
-                isThinClientEnabled: false);
-
-            DocumentServiceRequest primaryRequest = this.CreateRequest(isReadRequest: true, isMasterResourceType: false);
-            primaryRequest.Properties = sharedProperties;
-
-            // 1st 404/1002
-            primaryRetryPolicy.OnBeforeSendRequest(primaryRequest);
-            ShouldRetryResult shouldRetry = await primaryRetryPolicy.ShouldRetryAsync(
-                new DocumentClientException(
-                    message: "1st 404/1002",
-                    innerException: null,
-                    statusCode: HttpStatusCode.NotFound,
-                    substatusCode: SubStatusCodes.ReadSessionNotAvailable,
-                    requestUri: primaryRequest.RequestContext.LocationEndpointToRoute,
-                    responseHeaders: new DictionaryNameValueCollection()),
-                CancellationToken.None);
-            Assert.IsTrue(shouldRetry.ShouldRetry);
-
-            // 2nd 404/1002 → triggers shared state
-            primaryRetryPolicy.OnBeforeSendRequest(primaryRequest);
-            shouldRetry = await primaryRetryPolicy.ShouldRetryAsync(
-                new DocumentClientException(
-                    message: "2nd 404/1002",
-                    innerException: null,
-                    statusCode: HttpStatusCode.NotFound,
-                    substatusCode: SubStatusCodes.ReadSessionNotAvailable,
-                    requestUri: primaryRequest.RequestContext.LocationEndpointToRoute,
-                    responseHeaders: new DictionaryNameValueCollection()),
-                CancellationToken.None);
-            Assert.IsTrue(shouldRetry.ShouldRetry);
-
-            // Verify shared state was signaled
-            HubRegionProcessingState sharedState = (HubRegionProcessingState)sharedProperties[HubRegionProcessingState.RequestPropertyKey];
-            Assert.IsTrue(sharedState.ShouldAddHubRegionProcessingOnlyHeader,
-                "Shared state must be set to true after primary hits 2x 404/1002.");
-
-            // ---- HEDGED REQUEST: new retry policy, same shared Properties ----
-            ClientRetryPolicy hedgeRetryPolicy = new ClientRetryPolicy(
-                endpointManager,
-                this.partitionKeyRangeLocationCache,
-                new RetryOptions(),
-                enableEndpointDiscovery,
-                isThinClientEnabled: false);
-
-            DocumentServiceRequest hedgeRequest = this.CreateRequest(isReadRequest: true, isMasterResourceType: false);
-            hedgeRequest.Properties = sharedProperties;
-
-            // Hedge's FIRST OnBeforeSendRequest — should immediately see hub header via shared state
-            hedgeRetryPolicy.OnBeforeSendRequest(hedgeRequest);
-            string[] headerValues = hedgeRequest.Headers.GetValues(HubRegionHeader);
-            Assert.IsNotNull(headerValues,
-                "Hedged request must have hub region header on its first attempt (propagated via shared state).");
-            Assert.AreEqual(bool.TrueString, headerValues[0]);
-        }
-
         private async Task ValidateConnectTimeoutTriggersClientRetryPolicyAsync(
             bool isReadRequest,
             bool useMultipleWriteLocations,