Merge pull request #4867 from mbarnes/mbarnes/ARO-27472

Accept any API version on the operations endpoint

Author: bennerv

pkg/frontend/frontend.go

@@ -446,7 +446,16 @@ func (f *frontend) chiAuthenticatedRoutes(router chi.Router) {
 
 	r.Put("/subscriptions/{subscriptionId}", f.putSubscription)
 
-	r.With(f.apiVersionMiddleware.ValidateAPIVersion).Get("/providers/{resourceProviderNamespace}/operations", f.getOperations)
+	// Do not validate the API version on the operations endpoint. ARM will only route
+	// registered API versions to this service, but that may be an ARO-HCP version that
+	// this service does not recognize.
+	//
+	// The operations endpoint response must be identical across all API versions within
+	// this provider namespace regardless of which service the API version is meant for.
+	// To accomplish this, ARM uses a FanOut routing type for this endpoint. The request
+	// is "fanned out" to an ARO Classic and an ARO-HCP endpoint. Each service responds
+	// with its own set of operations, and ARM aggregates them for us.
+	r.Get("/providers/{resourceProviderNamespace}/operations", f.getOperations)
 }
 
 func notFound(w http.ResponseWriter, r *http.Request) {

pkg/frontend/operations_get_test.go

@@ -44,10 +44,10 @@ func TestGetOperations(t *testing.T) {
 			wantResponse:   allOperations,
 		},
 		{
-			name:           "api does not exist",
-			apiVersion:     "invalid",
-			wantStatusCode: http.StatusBadRequest,
-			wantError:      "400: InvalidResourceType: : The resource type '' could not be found in the namespace 'microsoft.redhatopenshift' for api version 'invalid'.",
+			name:           "unrecognized API version still returns operations",
+			apiVersion:     "2025-12-23-preview", // this is an ARO-HCP version
+			wantStatusCode: http.StatusOK,
+			wantResponse:   allOperations,
 		},
 	} {
 		t.Run(tt.name, func(t *testing.T) {