Remove arm-resource-flattening and migrate to explicity flattenProperty

specification/advisor/resource-manager/Microsoft.Advisor/Advisor/tspconfig.yaml

@@ -12,7 +12,7 @@ options:
     output-file: "{version-status}/{version}/openapi.json"
     examples-dir: "{project-root}/examples"
     arm-types-dir: "{project-root}/../../../../common-types/resource-management"
-    arm-resource-flattening: true
+
   "@azure-tools/typespec-python":
     emitter-output-dir: "{output-dir}/{service-dir}/azure-mgmt-advisor"
     namespace: "azure.mgmt.advisor"

specification/apicenter/ApiCenter.Management/back-compatible.tsp

@@ -0,0 +1,35 @@
+// Contains overrides to make the Autorest Swagger2.0 back compatible
+using Microsoft.ApiCenter;
+
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(Api.properties, "autorest");
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(ApiDefinition.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(ApiVersion.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(DeletedService.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(Deployment.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(Environment.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(MetadataSchema.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(Service.properties,
+  "autorest"
+);
+// For ServiceUpdate
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(Azure.ResourceManager.Foundations.ResourceUpdateModel.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(Workspace.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(ApiSource.properties,
+  "autorest"
+);

specification/apicenter/ApiCenter.Management/main.tsp

@@ -15,6 +15,7 @@ import "./ApiDefinition.tsp";
 import "./ApiSource.tsp";
 import "./Deployment.tsp";
 import "./Environment.tsp";
+import "./back-compatible.tsp";
 
 using TypeSpec.Rest;
 using TypeSpec.Http;

specification/apicenter/ApiCenter.Management/tspconfig.yaml

@@ -5,8 +5,6 @@ options:
     emitter-output-dir: "{project-root}/.."
     azure-resource-provider-folder: "resource-manager"
     emit-common-types-schema: "never"
-    # `arm-resource-flattening` is only used for back-compat for specs existed on July 2024. All new service spec should NOT use this flag
-    arm-resource-flattening: true
     output-file: "{azure-resource-provider-folder}/{service-name}/{version-status}/{version}/apicenter.json"
     use-read-only-status-schema: true
 linter:

specification/appcomplianceautomation/AppComplianceAutomation.Management/tspconfig.yaml

@@ -11,8 +11,6 @@ options:
     emitter-output-dir: "{project-root}/.."
     azure-resource-provider-folder: "resource-manager"
     emit-common-types-schema: "never"
-    # `arm-resource-flattening` is only used for back-compat for specs existed on July 2024. All new service spec should NOT use this flag
-    arm-resource-flattening: true
     output-file: "{azure-resource-provider-folder}/{service-name}/{version-status}/{version}/appcomplianceautomation.json"
   "@azure-tools/typespec-ts":
     experimental-extensible-enums: true

specification/appconfiguration/resource-manager/Microsoft.AppConfiguration/AppConfiguration/tspconfig.yaml

@@ -15,7 +15,7 @@ options:
     emit-lro-options: "all"
     examples-dir: "{project-root}/examples"
     arm-types-dir: "{project-root}/../../../../common-types/resource-management"
-    arm-resource-flattening: true
+
   "@azure-tools/typespec-python":
     emitter-output-dir: "{output-dir}/{service-dir}/azure-mgmt-appconfiguration"
     namespace: "azure.mgmt.appconfiguration"

specification/azuredependencymap/DependencyMap.Management/back-compatible.tsp

@@ -0,0 +1,11 @@
+import "@azure-tools/typespec-client-generator-core";
+
+using Microsoft.DependencyMap;
+
+// Discriminated type
+// @@Azure.ClientGenerator.Core.Legacy.flattenProperty(DiscoverySourceResource.properties,
+//   "autorest"
+// );
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(MapsResource.properties,
+  "autorest"
+);

specification/azuredependencymap/DependencyMap.Management/main.tsp

@@ -3,10 +3,11 @@ import "@typespec/versioning";
 import "@azure-tools/typespec-autorest";
 import "@azure-tools/typespec-azure-core";
 import "@azure-tools/typespec-azure-resource-manager";
+
 import "./models.tsp";
 import "./resources.tsp";
 import "./routes.tsp";
-//import "@azure-tools/typespec-providerhub";
+import "./back-compatible.tsp";
 
 using TypeSpec.Versioning;
 using Azure.ResourceManager;

specification/azuredependencymap/DependencyMap.Management/tspconfig.yaml

@@ -9,7 +9,7 @@ options:
     emitter-output-dir: "{project-root}/.."
     azure-resource-provider-folder: "resource-manager"
     output-file: "{azure-resource-provider-folder}/{service-name}/{version-status}/{version}/dependencyMap.json"
-    arm-resource-flattening: true
+
     version-enum-strategy: true
     emit-lro-options: "all"
   "@azure-typespec/http-client-csharp-mgmt":

specification/azuredependencymap/resource-manager/Microsoft.DependencyMap/preview/2025-01-31-preview/dependencyMap.json

@@ -1082,8 +1082,7 @@
       "properties": {
         "properties": {
           "$ref": "#/definitions/DiscoverySourceResourceProperties",
-          "description": "The resource-specific properties for this resource.",
-          "x-ms-client-flatten": true
+          "description": "The resource-specific properties for this resource."
         }
       },
       "allOf": [

specification/azuredependencymap/resource-manager/Microsoft.DependencyMap/preview/2025-05-01-preview/dependencyMap.json

@@ -1082,8 +1082,7 @@
       "properties": {
         "properties": {
           "$ref": "#/definitions/DiscoverySourceResourceProperties",
-          "description": "The resource-specific properties for this resource.",
-          "x-ms-client-flatten": true
+          "description": "The resource-specific properties for this resource."
         }
       },
       "allOf": [

specification/azuredependencymap/resource-manager/Microsoft.DependencyMap/preview/2025-07-01-preview/dependencyMap.json

@@ -1171,8 +1171,7 @@
       "properties": {
         "properties": {
           "$ref": "#/definitions/DiscoverySourceResourceProperties",
-          "description": "The resource-specific properties for this resource.",
-          "x-ms-client-flatten": true
+          "description": "The resource-specific properties for this resource."
         }
       },
       "allOf": [

specification/azurefleet/resource-manager/Microsoft.AzureFleet/AzureFleet/back-compatible.tsp

@@ -0,0 +1,7 @@
+import "@azure-tools/typespec-client-generator-core";
+
+using Microsoft.AzureFleet;
+
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(Fleet.properties,
+  "autorest"
+);

specification/azurefleet/resource-manager/Microsoft.AzureFleet/AzureFleet/main.tsp

@@ -8,6 +8,7 @@ import "./fleet.tsp";
 import "./baseVirtualMachineProfile.tsp";
 import "./virtualMachineScaleSet.tsp";
 import "./virtualMachine.tsp";
+import "./back-compatible.tsp";
 
 using TypeSpec.Http;
 using TypeSpec.Rest;

specification/azurefleet/resource-manager/Microsoft.AzureFleet/AzureFleet/tspconfig.yaml

@@ -14,8 +14,6 @@ options:
     emitter-output-dir: "{project-root}"
     azure-resource-provider-folder: "resource-manager"
     emit-common-types-schema: "never"
-    # `arm-resource-flattening` is only used for back-compat for specs existed on July 2024. All new service spec should NOT use this flag
-    arm-resource-flattening: true
     output-file: "{version-status}/{version}/azurefleet.json"
     arm-types-dir: "{project-root}/../../../../common-types/resource-management"
   "@azure-tools/typespec-csharp":

specification/azurelargeinstance/resource-manager/Microsoft.AzureLargeInstance/AzureLargeInstance/back-compatible.tsp

@@ -0,0 +1,11 @@
+// Contains overrides to make the Autorest Swagger2.0 back compatible
+
+using Microsoft.AzureLargeInstance;
+
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(AzureLargeInstance.properties,
+  "autorest"
+);
+
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(AzureLargeStorageInstance.properties,
+  "autorest"
+);

specification/azurelargeinstance/resource-manager/Microsoft.AzureLargeInstance/AzureLargeInstance/main.tsp

@@ -5,6 +5,7 @@ import "@azure-tools/typespec-azure-resource-manager";
 import "./models.tsp";
 import "./AzureLargeInstance.tsp";
 import "./AzureLargeStorageInstance.tsp";
+import "./back-compatible.tsp";
 
 using TypeSpec.Rest;
 using TypeSpec.Http;

specification/azurelargeinstance/resource-manager/Microsoft.AzureLargeInstance/AzureLargeInstance/tspconfig.yaml

@@ -8,7 +8,5 @@ options:
     emitter-output-dir: "{project-root}"
     azure-resource-provider-folder: "resource-manager"
     arm-types-dir: "{project-root}/../../../../common-types/resource-management"
-    # `arm-resource-flattening` is only used for back-compat for specs existed on July 2024. All new service spec should NOT use this flag
-    arm-resource-flattening: true
     output-file: "{version-status}/{version}/azurelargeinstance.json"
     use-read-only-status-schema: true

specification/azurestackhci/AzureStackHCI.StackHCIVM.Management/back-compatible.tsp

@@ -0,0 +1,40 @@
+import "@azure-tools/typespec-client-generator-core";
+
+using Microsoft.AzureStackHCI;
+
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(AttestationStatus.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(GalleryImage.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(GuestAgent.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(HybridIdentityMetadata.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(LogicalNetwork.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(MarketplaceGalleryImage.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(NetworkInterface.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(NetworkSecurityGroup.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(SecurityRule.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(StorageContainer.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(VirtualHardDisk.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(VirtualMachineInstance.properties,
+  "autorest"
+);

specification/azurestackhci/AzureStackHCI.StackHCIVM.Management/main.tsp

@@ -16,6 +16,8 @@ import "./VirtualMachineInstance.tsp";
 import "./HybridIdentityMetadata.tsp";
 import "./AttestationStatus.tsp";
 import "./GuestAgent.tsp";
+import "./back-compatible.tsp";
+
 using TypeSpec.Rest;
 using TypeSpec.Http;
 using Azure.Core;

specification/azurestackhci/AzureStackHCI.StackHCIVM.Management/tspconfig.yaml

@@ -9,8 +9,6 @@ options:
     emitter-output-dir: "{project-root}/.."
     azure-resource-provider-folder: "resource-manager"
     emit-common-types-schema: "never"
-    # `arm-resource-flattening` is only used for back-compat for specs existed on July 2024. All new service spec should NOT use this flag
-    arm-resource-flattening: true
     output-file: "{azure-resource-provider-folder}/{service-name}/StackHCIVM/{version-status}/{version}/stackhcivm.json"
   "@azure-tools/typespec-python":
     service-dir: "sdk/azurestackhci"

specification/azurestackhci/Operations.Management/tspconfig.yaml

@@ -6,8 +6,6 @@ options:
     emitter-output-dir: "{project-root}/.."
     azure-resource-provider-folder: "resource-manager"
     emit-common-types-schema: "never"
-    # `arm-resource-flattening` is only used for back-compat for specs existed on July 2024. All new service spec should NOT use this flag
-    arm-resource-flattening: true
     output-file: "{azure-resource-provider-folder}/{service-name}/operations/{version-status}/{version}/operations.json"
 linter:
   extends:

specification/cdn/resource-manager/Microsoft.Cdn/Cdn/tspconfig.yaml

@@ -11,7 +11,7 @@ options:
     output-file: "{version-status}/{version}/openapi.json"
     examples-dir: "{project-root}/examples"
     arm-types-dir: "{project-root}/../../../../common-types/resource-management"
-    arm-resource-flattening: true
+
     emit-lro-options: "all"
   "@azure-tools/typespec-python":
     emitter-output-dir: "{output-dir}/{service-dir}/azure-mgmt-cdn"

specification/chaos/resource-manager/Microsoft.Chaos/Chaos/back-compatible.tsp

@@ -34,3 +34,29 @@ using Microsoft.Chaos;
 @@clientName(Operations.list, "ListAll", "autorest");
 @@clientName(ExperimentExecutions.getExecutionDetails, "ExecutionDetails");
 @@clientName(PrivateAccesses.privateLinkResources, "GetPrivateLinkResources");
+
+// Flatten properties for backward compatibility
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(Capability.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(CapabilityType.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(ExperimentExecution.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(PrivateAccess.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(PrivateEndpointConnection.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(PrivateLinkResource.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(Target.properties,
+  "autorest"
+);
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(TargetType.properties,
+  "autorest"
+);

specification/chaos/resource-manager/Microsoft.Chaos/Chaos/tspconfig.yaml

@@ -7,8 +7,6 @@ options:
   "@azure-tools/typespec-autorest":
     azure-resource-provider-folder: "resource-manager"
     emit-common-types-schema: "never"
-    # `arm-resource-flattening` is only used for back-compat for specs existed on July 2024. All new service spec should NOT use this flag
-    arm-resource-flattening: true
     emitter-output-dir: "{project-root}"
     output-file: "{version-status}/{version}/openapi.json"
     arm-types-dir: "{project-root}/../../../../common-types/resource-management"

specification/codesigning/CodeSigning.Management/tspconfig.yaml

@@ -9,8 +9,6 @@ options:
     emitter-output-dir: "{project-root}/.."
     azure-resource-provider-folder: "resource-manager"
     emit-common-types-schema: "never"
-    # `arm-resource-flattening` is only used for back-compat for specs existed on July 2024. All new service spec should NOT use this flag
-    arm-resource-flattening: true
     output-file: "{azure-resource-provider-folder}/{service-name}/{version-status}/{version}/codeSigningAccount.json"
   "@azure-tools/typespec-java":
     emitter-output-dir: "{output-dir}/{service-dir}/azure-resourcemanager-trustedsigning"

specification/communitytraining/Community.Management/back-compatible.tsp

@@ -0,0 +1,10 @@
+// Contains overrides to make the Autorest Swagger2.0 back compatible
+using Microsoft.Community;
+
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(CommunityTraining.properties,
+  "autorest"
+);
+// For CommunityTrainingUpdate
+@@Azure.ClientGenerator.Core.Legacy.flattenProperty(Azure.ResourceManager.Foundations.ResourceUpdateModel.properties,
+  "autorest"
+);

specification/communitytraining/Community.Management/main.tsp

@@ -3,6 +3,9 @@ import "@typespec/rest";
 import "@typespec/versioning";
 import "@azure-tools/typespec-azure-core";
 import "@azure-tools/typespec-azure-resource-manager";
+import "@azure-tools/typespec-client-generator-core";
+
+import "./back-compatible.tsp";
 
 using TypeSpec.Http;
 using TypeSpec.Rest;

specification/communitytraining/Community.Management/tspconfig.yaml

@@ -5,8 +5,6 @@ options:
     emitter-output-dir: "{project-root}/.."
     azure-resource-provider-folder: "resource-manager"
     emit-common-types-schema: "never"
-    # `arm-resource-flattening` is only used for back-compat for specs existed on July 2024. All new service spec should NOT use this flag
-    arm-resource-flattening: true
     output-file: "{azure-resource-provider-folder}/{service-name}/{version-status}/{version}/CommunityTrainings.json"
 linter:
   extends:

specification/compute/Compute.Management/tspconfig.yaml

@@ -6,7 +6,7 @@ options:
     azure-resource-provider-folder: "resource-manager"
     output-file: "{azure-resource-provider-folder}/{service-name}/ComputeRP/{version-status}/{version}/ComputeRP.json"
     examples-dir: "{project-root}/examples"
-    arm-resource-flattening: true
+
 linter:
   extends:
     - "@azure-tools/typespec-azure-rulesets/resource-manager"

specification/compute/Disk.Management/tspconfig.yaml

@@ -7,7 +7,7 @@ options:
     azure-resource-provider-folder: "resource-manager"
     output-file: "{azure-resource-provider-folder}/{service-name}/DiskRP/{version-status}/{version}/DiskRP.json"
     examples-dir: "{project-root}/examples"
-    arm-resource-flattening: true
+
 linter:
   extends:
     - "@azure-tools/typespec-azure-rulesets/resource-manager"

specification/compute/Sku.Management/tspconfig.yaml

@@ -8,7 +8,7 @@ options:
     azure-resource-provider-folder: "resource-manager"
     output-file: "{azure-resource-provider-folder}/{service-name}/Skus/{version-status}/{version}/skus.json"
     examples-dir: "{project-root}/examples"
-    arm-resource-flattening: true
+
 linter:
   extends:
     - "@azure-tools/typespec-azure-rulesets/resource-manager"

specification/consumption/resource-manager/Microsoft.Consumption/Consumption/tspconfig.yaml

@@ -10,7 +10,7 @@ options:
     output-file: "{version-status}/{version}/openapi.json"
     emit-lro-options: "all"
     examples-dir: "{project-root}/examples"
-    arm-resource-flattening: true
+
     arm-types-dir: "{project-root}/../../../../common-types/resource-management"
   "@azure-tools/typespec-python":
     emitter-output-dir: "{output-dir}/{service-dir}/azure-mgmt-consumption"