[tcgc] deprecate Error usage and add Exception usage. for all models used in exception response, they will no longer have Output usage, but have Exception usage.

.chronus/changes/exception_usage-2024-10-13-11-50-32.md

@@ -0,0 +1,7 @@
+---
+changeKind: breaking
+packages:
+  - "@azure-tools/typespec-client-generator-core"
+---
+
+deprecate `Error` usage and add `Exception` usage. for all models used in exception response, they will no longer have `Output` usage, but have `Exception` usage.

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

@@ -730,12 +730,17 @@ export enum UsageFlags {
   MultipartFormData = 1 << 5,
   // Used in spread.
   Spread = 1 << 6,
+  /**
+   * @deprecated Use `Exception` instead.
+   */
   // Output will also be set when Error is set.
   Error = 1 << 7,
-  // Set when model is used in conjunction with an application/json content type.
+  // Set when type is used in conjunction with an application/json content type.
   Json = 1 << 8,
-  // Set when model is used in conjunction with an application/xml content type.
+  // Set when type is used in conjunction with an application/xml content type.
   Xml = 1 << 9,
+  // Set when type is used for exception output.
+  Exception = 1 << 10,
 }
 
 interface SdkExampleBase {

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

@@ -721,7 +721,7 @@ export function getSdkModelWithDiagnostics(
 
   if (!sdkType) {
     const name = getLibraryName(context, type) || getGeneratedName(context, type, operation);
-    const usage = isErrorModel(context.program, type) ? UsageFlags.Error : UsageFlags.None; // initial usage we can tell just by looking at the model
+    const usage = isErrorModel(context.program, type) ? UsageFlags.Error : UsageFlags.None; // eslint-disable-line @typescript-eslint/no-deprecated
     sdkType = {
       ...diagnostics.pipe(getSdkTypeBaseHelper(context, type, "model")),
       name: name,
@@ -1603,7 +1603,11 @@ function updateTypesFromOperation(
             : innerResponse.body.type;
         const sdkType = diagnostics.pipe(getClientTypeWithDiagnostics(context, body, operation));
         if (generateConvenient) {
-          diagnostics.pipe(updateUsageOrAccess(context, UsageFlags.Output, sdkType));
+          if (response.statusCodes === "*" || isErrorModel(context.program, body)) {
+            diagnostics.pipe(updateUsageOrAccess(context, UsageFlags.Exception, sdkType));
+          } else {
+            diagnostics.pipe(updateUsageOrAccess(context, UsageFlags.Output, sdkType));
+          }
 
           if (innerResponse.body.contentTypes.some((x) => isJsonContentType(x))) {
             diagnostics.pipe(updateUsageOrAccess(context, UsageFlags.Json, sdkType));

packages/typespec-client-generator-core/test/types/model-types.test.ts

@@ -1,5 +1,4 @@
 import { AzureCoreTestLibrary } from "@azure-tools/typespec-azure-core/testing";
-import { isErrorModel } from "@typespec/compiler";
 import { deepStrictEqual, ok, strictEqual } from "assert";
 import { beforeEach, describe, it } from "vitest";
 import { SdkBodyModelPropertyType, UsageFlags } from "../../src/interfaces.js";
@@ -1420,16 +1419,9 @@ describe("typespec-client-generator-core: model types", () => {
       `);
     const models = getAllModels(runner.context);
     strictEqual(models.length, 1);
-    strictEqual(models[0].kind, "model");
-    ok(models[0].usage & UsageFlags.Error);
-
     const model = models[0];
-    const rawModel = model.__raw;
-    ok(rawModel);
-    strictEqual(rawModel.kind, "Model");
-    strictEqual(isErrorModel(runner.context.program, rawModel), true);
-    ok(model.usage & UsageFlags.Output);
-    ok(model.usage & UsageFlags.Error);
+    strictEqual(model.kind, "model");
+    ok(model.usage & UsageFlags.Exception);
   });
 
   it("error model inheritance", async () => {