From db67beebd24a2366a9aa61781f1185bf554b059d Mon Sep 17 00:00:00 2001
From: Alitzel Mendez <6895254+AlitzelMendez@users.noreply.github.com>
Date: Thu, 23 Jan 2025 18:07:46 -0800
Subject: [PATCH]  Exclude template instances from the `no-response-body` rule.
 (#2085)

issue: https://github.com/Azure/typespec-azure/issues/1785
---
 ...ix-duplicate-warning-2025-0-15-11-39-29.md |  7 ++++
 .../src/rules/no-response-body.ts             |  9 ++++-
 .../test/rules/no-response-body.test.ts       | 38 +++++++++++++++++++
 3 files changed, 52 insertions(+), 2 deletions(-)
 create mode 100644 .chronus/changes/fix-duplicate-warning-2025-0-15-11-39-29.md

diff --git a/.chronus/changes/fix-duplicate-warning-2025-0-15-11-39-29.md b/.chronus/changes/fix-duplicate-warning-2025-0-15-11-39-29.md
new file mode 100644
index 0000000000..add103601c
--- /dev/null
+++ b/.chronus/changes/fix-duplicate-warning-2025-0-15-11-39-29.md
@@ -0,0 +1,7 @@
+---
+changeKind: fix
+packages:
+  - "@azure-tools/typespec-azure-resource-manager"
+---
+
+Exclude template instances from the `no-response-body` rule.
diff --git a/packages/typespec-azure-resource-manager/src/rules/no-response-body.ts b/packages/typespec-azure-resource-manager/src/rules/no-response-body.ts
index c518ef1502..33f39743db 100644
--- a/packages/typespec-azure-resource-manager/src/rules/no-response-body.ts
+++ b/packages/typespec-azure-resource-manager/src/rules/no-response-body.ts
@@ -1,4 +1,4 @@
-import { createRule, Operation } from "@typespec/compiler";
+import { createRule, isTemplateInstance, Operation } from "@typespec/compiler";
 import { getHttpOperation, getResponsesForOperation, HttpOperationResponse } from "@typespec/http";
 import { isTemplatedInterfaceOperation } from "./utils.js";
 /**
@@ -20,7 +20,12 @@ export const noResponseBodyRule = createRule({
     return {
       operation: (op: Operation) => {
         const [httpOperation] = getHttpOperation(context.program, op);
-        if (isTemplatedInterfaceOperation(op) || httpOperation.verb === "head") return;
+        if (
+          isTemplateInstance(op) ||
+          isTemplatedInterfaceOperation(op) ||
+          httpOperation.verb === "head"
+        )
+          return;
 
         const responses = getResponsesForOperation(context.program, op)[0].find(
           (v) => v.statusCodes !== 204 && v.statusCodes !== 202,
diff --git a/packages/typespec-azure-resource-manager/test/rules/no-response-body.test.ts b/packages/typespec-azure-resource-manager/test/rules/no-response-body.test.ts
index 957a919511..6c75757f78 100644
--- a/packages/typespec-azure-resource-manager/test/rules/no-response-body.test.ts
+++ b/packages/typespec-azure-resource-manager/test/rules/no-response-body.test.ts
@@ -153,4 +153,42 @@ describe("typespec-azure-resource-manager: no response body rule", () => {
       )
       .toBeValid();
   });
+
+  it("allows templates but emit on use of the template ", async () => {
+    await tester
+      .expect(
+        `
+          @armProviderNamespace
+          @useDependency(Azure.ResourceManager.Versions.v1_0_Preview_1)
+          namespace Microsoft.ContosoProviderHub;
+
+          op SampleTemplate<
+            Resource extends Foundations.Resource,
+            Response extends {} = ArmResponse<Resource>
+          > is ArmCustomPatchAsync<Resource, Response = Response>;
+
+          model Image is Azure.ResourceManager.TrackedResource<{name: string}> {
+            ...ResourceNameParameter<
+              Resource = Image
+            >;
+          }
+
+          @armResourceOperations
+          interface Images {
+            @parameterVisibility
+            update is SampleTemplate<
+              Image,
+              Response =  (ArmAcceptedLroResponse<LroHeaders = Azure.Core.Foundations.RetryAfterHeader &
+                ArmLroLocationHeader<FinalResult = Image>> & {
+                @body _: Image;
+              })
+            >;
+          }
+        `,
+      )
+      .toEmitDiagnostics({
+        code: "@azure-tools/typespec-azure-resource-manager/no-response-body",
+        message: `The body of 202 response should be empty.`,
+      });
+  });
 });