fix(mock): inline enum values in mocks for union enumGenerationType (#3694)

Author: wadakatu

packages/mock/src/faker/getters/scalar.test.ts

@@ -1,5 +1,6 @@
 /* eslint-disable unicorn/no-null */
 import type { ContextSpec, OpenApiSchemaObjectType } from '@orval/core';
+import { EnumGeneration } from '@orval/core';
 import { describe, expect, it } from 'vitest';
 
 import { createTestContextSpec } from '../../../../core/src/test-utils/context';
@@ -1166,3 +1167,66 @@ describe('getMockScalar (schema-scoped overrides)', () => {
     expect(result.value).toBe("'red'");
   });
 });
+
+describe('getMockScalar (referenced string enum by enumGenerationType #3690)', () => {
+  const baseArg = {
+    imports: [],
+    operationId: 'test-operation',
+    tags: [],
+    existingReferencedProperties: [],
+    splitMockImplementations: [],
+  };
+
+  const enumRefItem = {
+    type: 'string' as OpenApiSchemaObjectType,
+    enum: ['ONE', 'TWO', 'THREE'],
+    name: 'MyEnum',
+    isRef: true,
+  };
+
+  it('inlines the enum values for `union` (a union type has no runtime value)', () => {
+    const result = getMockScalar({
+      ...baseArg,
+      item: { ...enumRefItem },
+      context: scalarContext({ enumGenerationType: EnumGeneration.UNION }),
+    });
+
+    expect(result.value).toBe(
+      "faker.helpers.arrayElement(['ONE','TWO','THREE'] as const)",
+    );
+    // No value import: the union type must not be referenced as a value.
+    expect(result.imports).not.toContainEqual(
+      expect.objectContaining({ name: 'MyEnum', values: true }),
+    );
+  });
+
+  it('uses Object.values for `enum` (a native enum is a runtime object)', () => {
+    const result = getMockScalar({
+      ...baseArg,
+      item: { ...enumRefItem },
+      context: scalarContext({ enumGenerationType: EnumGeneration.ENUM }),
+    });
+
+    expect(result.value).toBe(
+      'faker.helpers.arrayElement(Object.values(MyEnum))',
+    );
+    expect(result.imports).toContainEqual(
+      expect.objectContaining({ name: 'MyEnum', values: true }),
+    );
+  });
+
+  it('uses Object.values for `const` (a const object is a runtime value)', () => {
+    const result = getMockScalar({
+      ...baseArg,
+      item: { ...enumRefItem },
+      context: scalarContext({ enumGenerationType: EnumGeneration.CONST }),
+    });
+
+    expect(result.value).toBe(
+      'faker.helpers.arrayElement(Object.values(MyEnum))',
+    );
+    expect(result.imports).toContainEqual(
+      expect.objectContaining({ name: 'MyEnum', values: true }),
+    );
+  });
+});

packages/mock/src/faker/getters/scalar.ts

@@ -635,8 +635,16 @@ function getEnum(
     enumValue += ' as const';
   }
 
-  // But if the value is a reference, we can use the object directly via the imports and using Object.values.
-  if (item.isRef && type === 'string') {
+  // But if the value is a reference to a schema that emits a runtime value
+  // (a native `enum` object or a `const` object), we can use it directly via
+  // the imports and `Object.values`. A `union` reference is a pure type with
+  // no runtime value, so `Object.values` would fail (TS2693) — keep the
+  // inlined values in that case (#3690).
+  if (
+    item.isRef &&
+    type === 'string' &&
+    context.output.override.enumGenerationType !== EnumGeneration.UNION
+  ) {
     enumValue = `Object.values(${item.name})`;
     imports.push({
       name: item.name,

packages/mock/src/faker/index.test.ts

@@ -10,7 +10,12 @@ import type {
   NormalizedOverrideOutput,
   OpenApiSchemaObject,
 } from '@orval/core';
-import { isFakerMock, isMswMock, OutputMockType } from '@orval/core';
+import {
+  EnumGeneration,
+  isFakerMock,
+  isMswMock,
+  OutputMockType,
+} from '@orval/core';
 import { describe, expect, expectTypeOf, it } from 'vitest';
 
 import { createTestContextSpec } from '../../../core/src/test-utils/context';
@@ -534,7 +539,11 @@ describe('oneOf split helpers forward body imports (#3656)', () => {
   // mutating that array suppresses the caller-side merge of the returned
   // imports, so forwarding only the variant's type import loses the enum
   // value import and the generated mock fails tsc with TS2304.
+  // `enum` generation makes the $ref'd enum a runtime object, so the helper
+  // renders it as `Object.values(ReasonEnum)` (see #3690 — `union` inlines the
+  // values instead and forwards no value import).
   const context = createTestContextSpec({
+    override: { enumGenerationType: EnumGeneration.ENUM },
     spec: {
       components: {
         schemas: {

tests/__snapshots__/mock/union-enum-ref-msw/endpoints.ts

@@ -0,0 +1,72 @@
+/**
+ * Generated by orval v8.20.0 🍺
+ * Do not edit manually.
+ * Union enum ref mock
+ * A parent schema references a string enum component via $ref while
+ * enumGenerationType is 'union'. The union renders the enum as a pure type
+ * (no runtime value), so the generated faker/msw mock must inline the enum
+ * values instead of calling Object.values(EnumName) — which would fail tsc
+ * with TS2693 (#3690).
+ *
+ * OpenAPI spec version: 1.0.0
+ */
+import axios from 'axios';
+import type { AxiosInstance, AxiosRequestConfig, AxiosResponse } from 'axios';
+
+import type { DisplayValueDto } from './model';
+
+import { faker } from '@faker-js/faker';
+
+import { HttpResponse, http } from 'msw';
+import type { RequestHandlerOptions } from 'msw';
+
+export const getUnionEnumRefMock = (axiosInstance: AxiosInstance = axios) => {
+  const getDisplay = (
+    options?: AxiosRequestConfig,
+  ): Promise<AxiosResponse<DisplayValueDto>> => {
+    return axiosInstance.get(`/display`, options);
+  };
+
+  return { getDisplay };
+};
+export type GetDisplayResult = AxiosResponse<DisplayValueDto>;
+
+export const getGetDisplayResponseMock = (
+  overrideResponse: Partial<Extract<DisplayValueDto, object>> = {},
+): DisplayValueDto => ({
+  color: faker.helpers.arrayElement([
+    faker.helpers.arrayElement([
+      'TEXT_01',
+      'TEXT_04',
+      'TEXT_CURRENCY_GAIN',
+    ] as const),
+    undefined,
+  ]),
+  value: faker.string.alpha({ length: { min: 10, max: 20 } }),
+  ...overrideResponse,
+});
+
+export const getGetDisplayMockHandler = (
+  overrideResponse?:
+    | DisplayValueDto
+    | ((
+        info: Parameters<Parameters<typeof http.get>[1]>[0],
+      ) => Promise<DisplayValueDto> | DisplayValueDto),
+  options?: RequestHandlerOptions,
+) => {
+  return http.get(
+    '*/display',
+    async (info: Parameters<Parameters<typeof http.get>[1]>[0]) => {
+      return HttpResponse.json(
+        overrideResponse !== undefined
+          ? typeof overrideResponse === 'function'
+            ? await overrideResponse(info)
+            : overrideResponse
+          : getGetDisplayResponseMock(),
+        { status: 200 },
+      );
+    },
+    options,
+  );
+};
+export const getUnionEnumRefMockMock = () => [getGetDisplayMockHandler()];

tests/__snapshots__/mock/union-enum-ref-msw/model/displayColor.ts

@@ -0,0 +1,17 @@
+/**
+ * Generated by orval v8.20.0 🍺
+ * Do not edit manually.
+ * Union enum ref mock
+ * A parent schema references a string enum component via $ref while
+ * enumGenerationType is 'union'. The union renders the enum as a pure type
+ * (no runtime value), so the generated faker/msw mock must inline the enum
+ * values instead of calling Object.values(EnumName) — which would fail tsc
+ * with TS2693 (#3690).
+ *
+ * OpenAPI spec version: 1.0.0
+ */
+
+/**
+ * A text color that can be used for display purposes.
+ */
+export type DisplayColor = 'TEXT_01' | 'TEXT_04' | 'TEXT_CURRENCY_GAIN';

tests/__snapshots__/mock/union-enum-ref-msw/model/displayValueDto.ts

@@ -0,0 +1,18 @@
+/**
+ * Generated by orval v8.20.0 🍺
+ * Do not edit manually.
+ * Union enum ref mock
+ * A parent schema references a string enum component via $ref while
+ * enumGenerationType is 'union'. The union renders the enum as a pure type
+ * (no runtime value), so the generated faker/msw mock must inline the enum
+ * values instead of calling Object.values(EnumName) — which would fail tsc
+ * with TS2693 (#3690).
+ *
+ * OpenAPI spec version: 1.0.0
+ */
+import type { DisplayColor } from './displayColor';
+
+export interface DisplayValueDto {
+  color?: DisplayColor;
+  value: string;
+}

tests/__snapshots__/mock/union-enum-ref-msw/model/index.ts

@@ -0,0 +1,15 @@
+/**
+ * Generated by orval v8.20.0 🍺
+ * Do not edit manually.
+ * Union enum ref mock
+ * A parent schema references a string enum component via $ref while
+ * enumGenerationType is 'union'. The union renders the enum as a pure type
+ * (no runtime value), so the generated faker/msw mock must inline the enum
+ * values instead of calling Object.values(EnumName) — which would fail tsc
+ * with TS2693 (#3690).
+ *
+ * OpenAPI spec version: 1.0.0
+ */
+
+export * from './displayColor';
+export * from './displayValueDto';

tests/configs/mock.config.ts

@@ -545,6 +545,27 @@ export default defineConfig({
       target: '../specifications/faker-schemas-string-enum-ref.yaml',
     },
   },
+  // #3690: with `enumGenerationType: 'union'` a $ref'd string enum is a pure
+  // type (no runtime value), so the msw/faker mock must inline the enum values
+  // instead of calling `Object.values(EnumName)` (which fails tsc with TS2693).
+  unionEnumRefMsw: {
+    output: {
+      target: '../generated/mock/union-enum-ref-msw/endpoints.ts',
+      schemas: '../generated/mock/union-enum-ref-msw/model',
+      client: 'axios',
+      mock: {
+        generators: [{ type: 'msw' }],
+      },
+      override: {
+        enumGenerationType: 'union',
+      },
+      clean: true,
+      formatter: 'prettier',
+    },
+    input: {
+      target: '../specifications/union-enum-ref-mock.yaml',
+    },
+  },
   issue3200: {
     output: {
       target: '../generated/mock/issue-3200/endpoints.ts',

tests/specifications/union-enum-ref-mock.yaml

@@ -0,0 +1,40 @@
+openapi: 3.0.3
+info:
+  title: Union enum ref mock
+  description: |
+    A parent schema references a string enum component via $ref while
+    enumGenerationType is 'union'. The union renders the enum as a pure type
+    (no runtime value), so the generated faker/msw mock must inline the enum
+    values instead of calling Object.values(EnumName) — which would fail tsc
+    with TS2693 (#3690).
+  version: 1.0.0
+paths:
+  /display:
+    get:
+      operationId: getDisplay
+      responses:
+        '200':
+          description: OK
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/DisplayValueDto'
+components:
+  schemas:
+    DisplayColor:
+      description: A text color that can be used for display purposes.
+      type: string
+      enum:
+        - TEXT_01
+        - TEXT_04
+        - TEXT_CURRENCY_GAIN
+    DisplayValueDto:
+      type: object
+      required:
+        - value
+      properties:
+        color:
+          allOf:
+            - $ref: '#/components/schemas/DisplayColor'
+        value:
+          type: string