Address no-client warning review feedback

Author: msyyc

packages/http-client-python/emitter/src/emitter.ts

@@ -1,5 +1,5 @@
 import { createSdkContext } from "@azure-tools/typespec-client-generator-core";
-import type { EmitContext, Namespace, Program } from "@typespec/compiler";
+import type { DiagnosticTarget, EmitContext, Program } from "@typespec/compiler";
 import { emitFile, joinPaths, listServices, NoTarget } from "@typespec/compiler";
 import pkgJson from "../../package.json" with { type: "json" };
 import { emitCodeModel } from "./code-model.js";
@@ -128,8 +128,8 @@ async function runPyodideGeneration(
   await pyodide.runPythonAsync(pyodideGenerationCode, { globals });
 }
 
-export function getNoSdkClientsDiagnosticTarget(program: Program): Namespace {
-  return listServices(program)[0].type;
+export function getNoSdkClientsDiagnosticTarget(program: Program): DiagnosticTarget {
+  return listServices(program)[0]?.type ?? NoTarget;
 }
 
 async function copyPyodideOutputToHost(
@@ -191,7 +191,6 @@ async function onEmitMain(context: EmitContext<PythonEmitterOptions>) {
       code: "no-sdk-clients",
       target: getNoSdkClientsDiagnosticTarget(program),
     });
-    // return;
   }
 
   const resolvedOptions = sdkContext.emitContext.options;

packages/http-client-python/emitter/test/emitter.test.ts

@@ -1,4 +1,4 @@
-import { resolvePath } from "@typespec/compiler";
+import { NoTarget, resolvePath } from "@typespec/compiler";
 import { createTester, t } from "@typespec/compiler/testing";
 import { strictEqual } from "assert";
 import { it } from "vitest";
@@ -22,3 +22,16 @@ it("targets the service namespace when no SDK clients are found", async () => {
     false,
   );
 });
+
+it("uses no target when no service exists", async () => {
+  const { program } = await Tester.compile(`model Widget {}`);
+
+  const target = getNoSdkClientsDiagnosticTarget(program);
+  strictEqual(target, NoTarget);
+
+  reportDiagnostic(program, { code: "no-sdk-clients", target });
+  strictEqual(
+    program.diagnostics.some((x) => x.code.endsWith("/no-sdk-clients")),
+    true,
+  );
+});