scope resource support.

eng/packages/http-client-csharp-mgmt/generator/Azure.Generator.Management/src/Models/RequestPathPattern.cs

@@ -29,18 +29,19 @@ internal class RequestPathPattern : IEquatable<RequestPathPattern>, IReadOnlyLis
         public static readonly RequestPathPattern ManagementGroup = new("/providers/Microsoft.Management/managementGroups/{managementGroupId}");
         public static readonly RequestPathPattern ResourceGroup = new("/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}");
         public static readonly RequestPathPattern Subscription = new("/subscriptions/{subscriptionId}");
-        public static readonly RequestPathPattern Extension = new("/{resourceUri}");
-
         public static readonly RequestPathPattern Tenant = new(string.Empty);
 
-        public static RequestPathPattern GetFromScope(ResourceScope scope)
+        public static RequestPathPattern GetFromScope(ResourceScope scope, RequestPathPattern? path = null)
         {
             return scope switch
             {
                 ResourceScope.ResourceGroup => ResourceGroup,
                 ResourceScope.Subscription => Subscription,
                 ResourceScope.ManagementGroup => ManagementGroup,
-                ResourceScope.Extension => Extension,
+                ResourceScope.Extension =>
+                    path is null
+                        ? throw new InvalidOperationException("Extension scope requires a path parameter.")
+                        : new RequestPathPattern(path._segments.Take(1)),
                 ResourceScope.Tenant => Tenant,
                 _ => throw new InvalidOperationException($"Unhandled scope {scope}"),
             };

eng/packages/http-client-csharp-mgmt/generator/Azure.Generator.Management/src/Models/ResourceMetadata.cs

@@ -52,7 +52,7 @@ internal static ResourceMetadata DeserializeResourceMetadata(IReadOnlyDictionary
                 }
 
                 //TODO: handle Extension resource in emitter
-                if (resourceIdPattern is not null && resourceIdPattern.StartsWith("/{resourceUri}/"))
+                if (resourceIdPattern is not null && (resourceIdPattern.StartsWith("/{resourceUri}/") || resourceIdPattern.StartsWith("/{scope}/")))
                 {
                     resourceScope = ResourceScope.Extension;
                 }

eng/packages/http-client-csharp-mgmt/generator/Azure.Generator.Management/src/Providers/ResourceCollectionClientProvider.cs

@@ -71,6 +71,15 @@ private static RequestPathPattern GetContextualRequestPattern(ResourceMetadata r
                 return new RequestPathPattern(resourceMetadata.ParentResourceId);
             }
 
+            if (resourceMetadata.ResourceScope == ResourceScope.Extension)
+            {
+                if (string.IsNullOrEmpty(resourceMetadata.ResourceIdPattern))
+                {
+                    throw new InvalidOperationException("Extension resource's IdPattern can't be empty or null.");
+                }
+                return RequestPathPattern.GetFromScope(resourceMetadata.ResourceScope, new RequestPathPattern(resourceMetadata.ResourceIdPattern));
+            }
+
             return RequestPathPattern.GetFromScope(resourceMetadata.ResourceScope);
         }
 

eng/packages/http-client-csharp-mgmt/generator/Azure.Generator.Management/src/Utilities/ContextualParameterBuilder.cs

@@ -60,9 +60,10 @@ private static void BuildContextualParameterHierarchy(RequestPathPattern current
                 // using the reference name of the last segment as the parameter name, aka resourceGroupName
                 parameterStack.Push(new ContextualParameter(current[^2].Value, current[^1].VariableName, id => id.ResourceGroupName()));
             }
-            else if (current == RequestPathPattern.Extension)
+            else if (current.Count == 1 && !current[0].IsConstant) // Extension resource case: single variable segment. Here we assume the extension resource's requestPathPattern start with one and only one variable segment
             {
-                parameterStack.Push(new ContextualParameter("resourceUri", "resourceUri", id => BuildParentInvocation(parentLayerCount, id)));
+                // Extension resource case: single variable segment
+                parameterStack.Push(new ContextualParameter(current[0].VariableName, current[0].VariableName, id => BuildParentInvocation(parentLayerCount, id)));
             }
             else
             {

eng/packages/http-client-csharp-mgmt/generator/TestProjects/Local/Mgmt-TypeSpec/main.tsp

@@ -7,6 +7,7 @@ import "./baz.tsp";
 import "./zoo.tsp";
 import "./routes.tsp";
 import "./endpoint.tsp";
+import "./selfhelp.tsp";
 
 using TypeSpec.Versioning;
 using Azure.ClientGenerator.Core;

eng/packages/http-client-csharp-mgmt/generator/TestProjects/Local/Mgmt-TypeSpec/selfhelp.tsp

@@ -0,0 +1,30 @@
+import "@azure-tools/typespec-azure-core";
+import "@azure-tools/typespec-azure-resource-manager";
+import "@typespec/openapi";
+import "@typespec/rest";
+
+using Azure.ResourceManager;
+using TypeSpec.Http;
+using TypeSpec.OpenAPI;
+
+namespace MgmtTypeSpec;
+
+model SelfHelpResource
+  is Azure.ResourceManager.ExtensionResource<SelfHelpResourceProperties> {
+  ...ResourceNameParameter<
+    Resource = SelfHelpResource,
+    KeyName = "selfHelpName",
+    SegmentName = "selfHelps",
+    NamePattern = ""
+  >;
+}
+
+model SelfHelpResourceProperties {
+  selfHelpId: string;
+}
+
+#suppress "@azure-tools/typespec-azure-resource-manager/no-resource-delete-operation" "FIXME: Update justification, follow aka.ms/tsp/conversion-fix for details"
+@armResourceOperations
+interface SolutionResources {
+  get is Extension.Read<Extension.ScopeParameter, SelfHelpResource>;
+}