[tcgc] add linter rulesets framework

docs/libraries/typespec-client-generator-core/rules/require-client-suffix.md

@@ -0,0 +1,44 @@
+---
+title: "require-client-suffix"
+---
+
+```text title="Full name"
+@azure-tools/typespec-client-generator-core/require-client-suffix
+```
+
+Verify that the generated client's name will have the suffix `Client` in its name
+
+#### ❌ Incorrect
+
+```ts
+// main.tsp
+namespace MyService;
+```
+
+```ts
+// client.tsp
+import "@azure-tools/typespec-client-generator-core";
+import "./main.tsp";
+
+using Azure.ClientGenerator.Core;
+
+namespace MyCustomizations;
+
+@@client(MyService);
+```
+
+#### ✅ Ok
+
+Either you can rename the client using input param `{"name": "MyClient"}`, or if you are completely recreating a client namespace in your `client.tsp`, you can rely on that namespace to end in `Client`
+
+```ts
+// client.tsp
+import "@azure-tools/typespec-client-generator-core";
+import "./main.tsp";
+
+using Azure.ClientGenerator.Core;
+
+@client({service: MyService})
+namespace MyClient {
+}
+```

packages/typespec-client-generator-core/src/decorators.ts

@@ -157,13 +157,6 @@ export const $client: ClientDecorator = (
     explicitService?.kind === "Namespace"
       ? explicitService
       : findClientService(context.program, target) ?? (target as any);
-  if (!name.endsWith("Client")) {
-    reportDiagnostic(context.program, {
-      code: "client-name",
-      format: { name },
-      target: context.decoratorTarget,
-    });
-  }
 
   if (!isService(context.program, service)) {
     reportDiagnostic(context.program, {
@@ -781,7 +774,7 @@ export const $clientFormat: ClientFormatDecorator = (
     setScopedDecoratorData(context, $clientFormat, clientFormatKey, target, format, scope); // eslint-disable-line deprecation/deprecation
   } else {
     reportDiagnostic(context.program, {
-      code: "incorrect-client-format",
+      code: "invalid-client-format",
       format: { format, expectedTargetTypes: expectedTargetTypes.join('", "') },
       target: context.decoratorTarget,
     });
@@ -929,7 +922,7 @@ export const $access: AccessDecorator = (
 ) => {
   if (typeof value.value !== "string" || (value.value !== "public" && value.value !== "internal")) {
     reportDiagnostic(context.program, {
-      code: "access",
+      code: "incorrect-access",
       format: {},
       target: entity,
     });

packages/typespec-client-generator-core/src/index.ts

@@ -1,6 +1,7 @@
 export * from "./decorators.js";
 export * from "./interfaces.js";
 export * from "./lib.js";
+export { $linter } from "./linter.js";
 export * from "./public-utils.js";
 export * from "./types.js";
 export { $onValidate } from "./validate.js";

packages/typespec-client-generator-core/src/lib.ts

@@ -3,25 +3,13 @@ import { createTypeSpecLibrary, paramMessage } from "@typespec/compiler";
 export const $lib = createTypeSpecLibrary({
   name: "@azure-tools/typespec-client-generator-core",
   diagnostics: {
-    "client-name": {
-      severity: "warning",
-      messages: {
-        default: paramMessage`Client name "${"name"}" must end with Client. Use @client({name: "...Client"}`,
-      },
-    },
     "client-service": {
       severity: "warning",
       messages: {
         default: paramMessage`Client "${"name"}" is not inside a service namespace. Use @client({service: MyServiceNS}`,
       },
     },
-    "unknown-client-format": {
-      severity: "error",
-      messages: {
-        default: paramMessage`Client format "${"format"}" is unknown. Known values are "${"knownValues"}"`,
-      },
-    },
-    "incorrect-client-format": {
+    "invalid-client-format": {
       severity: "error",
       messages: {
         default: paramMessage`Format "${"format"}" can only apply to "${"expectedTargetTypes"}"`,
@@ -33,22 +21,7 @@ export const $lib = createTypeSpecLibrary({
         default: "Cannot have a union containing only null types.",
       },
     },
-    "union-unsupported": {
-      severity: "error",
-      messages: {
-        default:
-          "Unions cannot be emitted by our language generators unless all options are literals of the same type.",
-        null: "Unions containing multiple model types cannot be emitted unless the union is between one model type and 'null'.",
-      },
-    },
-    "use-enum-instead": {
-      severity: "warning",
-      messages: {
-        default:
-          "Use enum instead of union of string or number literals. Falling back to the literal type.",
-      },
-    },
-    access: {
+    "invalid-access": {
       severity: "error",
       messages: {
         default: `Access decorator value must be "public" or "internal".`,
@@ -60,13 +33,6 @@ export const $lib = createTypeSpecLibrary({
         default: `Usage decorator value must be 2 ("input") or 4 ("output").`,
       },
     },
-    "invalid-encode": {
-      severity: "error",
-      messages: {
-        default: "Invalid encoding",
-        wrongType: paramMessage`Encoding '${"encoding"}' cannot be used on type '${"type"}'`,
-      },
-    },
     "conflicting-multipart-model-usage": {
       severity: "error",
       messages: {

packages/typespec-client-generator-core/src/linter.ts

@@ -0,0 +1,7 @@
+import { defineLinter } from "@typespec/compiler";
+import { requireClientSuffixRule } from "./rules/require-client-suffix.js";
+
+
+export const $linter = defineLinter({
+  rules: [requireClientSuffixRule],
+});

packages/typespec-client-generator-core/src/rules/require-client-suffix.ts

@@ -0,0 +1,39 @@
+import { createRule, Interface, Namespace, paramMessage } from "@typespec/compiler";
+import { getClient } from "../decorators.js";
+import { createTCGCContext } from "../internal-utils.js";
+
+export const requireClientSuffixRule = createRule({
+  name: "require-client-suffix",
+  description: "Client names should end with 'Client'.",
+  severity: "warning",
+  messages: {
+    default: paramMessage`Client name "${"name"}" must end with Client. Use @client({name: "...Client"}`,
+  },
+  create(context) {
+    const tcgcContext = createTCGCContext(context.program);
+    return {
+      namespace: (namespace: Namespace) => {
+        const sdkClient = getClient(tcgcContext, namespace);
+        if (sdkClient && !sdkClient.name.endsWith("Client")) {
+          context.reportDiagnostic({
+            target: namespace,
+            format: {
+              name: sdkClient.name,
+            },
+          });
+        }
+      },
+      interface: (interfaceType: Interface) => {
+        const sdkClient = getClient(tcgcContext, interfaceType);
+        if (sdkClient && !sdkClient.name.endsWith("Client")) {
+          context.reportDiagnostic({
+            target: interfaceType,
+            format: {
+              name: sdkClient.name,
+            },
+          });
+        }
+      },
+    };
+  },
+});

packages/typespec-client-generator-core/test/rules/require-client-suffix.test.ts

@@ -0,0 +1,43 @@
+import {
+  BasicTestRunner,
+  createLinterRuleTester,
+  LinterRuleTester,
+} from "@typespec/compiler/testing";
+import { beforeEach, describe, it } from "vitest";
+import { requireClientSuffixRule } from "../../src/rules/require-client-suffix.js";
+import { createTcgcTestRunner } from "../test-host.js";
+
+describe("typespec-client-generator-core: client names end with 'Client'", () => {
+  let runner: BasicTestRunner;
+  let tester: LinterRuleTester;
+
+  beforeEach(async () => {
+    runner = await createTcgcTestRunner();
+    tester = createLinterRuleTester(
+      runner,
+      requireClientSuffixRule,
+      "@azure-tools/typespec-client-generator-core"
+    );
+  });
+
+  it("namespace", async () => {
+    await tester
+      .expect(
+        `
+      @service
+      namespace MyService;
+
+      namespace MyCustomizations {
+        @@client(MyService);
+      }
+      `
+      )
+      .toEmitDiagnostics([
+        {
+          code: "@azure-tools/typespec-client-generator-core/require-client-suffix",
+          severity: "warning",
+          message: `Client name "MyNamespace" must end with Client. Use @client({name: "...Client"}`,
+        },
+      ]);
+  });
+});

packages/typespec-client-generator-core/test/test-host.ts

@@ -68,6 +68,19 @@ export interface CreateSdkTestRunnerOptions extends SdkEmitterOptions {
   packageName?: string;
 }
 
+export async function createTcgcTestRunner(): Promise<SdkTestRunner> {
+  const host = await createSdkTestHost();
+  const autoUsings = [
+    "Azure.ClientGenerator.Core",
+    "TypeSpec.Rest",
+    "TypeSpec.Http",
+    "TypeSpec.Versioning",
+  ];
+  return createTestWrapper(host, {
+    autoUsings: autoUsings,
+  }) as SdkTestRunner;
+}
+
 export async function createSdkTestRunner(
   options: CreateSdkTestRunnerOptions = {},
   sdkContextOption?: CreateSdkContextOptions