Fix wild key issue

.changepacks/changepack_log_PICQGAdJ559UmGGsfIaks.json

@@ -0,0 +1 @@
+{"changes":{"packages/generator/package.json":"Patch"},"note":"Fix wild key issue","date":"2026-04-17T09:02:19.475575400Z"}

packages/generator/src/__tests__/generate-interface.test.ts

@@ -2532,3 +2532,55 @@ test('generateInterface preserves JSON endpoints alongside form/multipart endpoi
   // Raw multipart should use FormData | Record<string, unknown>
   expect(result).toContain('FormData | Record<string, unknown>')
 })
+
+test('generateInterface emits index signature for additionalProperties (not quoted key)', () => {
+  const schema = {
+    paths: {
+      '/news-categories': {
+        post: {
+          operationId: 'createNewsCategory',
+          requestBody: {
+            content: {
+              'application/json': {
+                schema: {
+                  $ref: '#/components/schemas/NewsCategoryCreateRequest',
+                },
+              },
+            },
+          },
+          responses: {
+            '201': {
+              description: 'Created',
+              content: {
+                'application/json': {
+                  schema: { type: 'string' as const },
+                },
+              },
+            },
+          },
+        },
+      },
+    },
+    components: {
+      schemas: {
+        NewsCategoryCreateRequest: {
+          type: 'object' as const,
+          properties: {
+            title: {
+              type: 'object' as const,
+              properties: {},
+              required: [],
+              additionalProperties: { type: 'string' as const },
+            },
+          },
+          required: ['title'],
+        },
+      },
+    },
+  }
+  const result = generateInterface(createSchemas(createDocument(schema as any)))
+  // Must emit a real TS index signature
+  expect(result).toContain('[key: string]: string')
+  // Must NOT emit a quoted literal key
+  expect(result).not.toContain("'[key: string]'")
+})

packages/generator/src/__tests__/wrap-interface-key-guard.test.ts

@@ -67,3 +67,11 @@ test.each([
 ] as const)('wrapInterfaceKeyGuard handles optional keys (ending with ?): %s -> %s', (key, expected) => {
   expect(wrapInterfaceKeyGuard(key)).toBe(expected)
 })
+
+test.each([
+  ['[key: string]', '[key: string]'],
+  ['[key: number]', '[key: number]'],
+  ['[k: string]', '[k: string]'],
+] as const)('wrapInterfaceKeyGuard preserves index signature syntax: %s -> %s', (key, expected) => {
+  expect(wrapInterfaceKeyGuard(key)).toBe(expected)
+})

packages/generator/src/wrap-interface-key-guard.ts

@@ -4,6 +4,11 @@ export function wrapInterfaceKeyGuard(key: string): string {
     return key
   }
 
+  // Preserve TypeScript index signature syntax (e.g., [key: string], [key: number])
+  if (/^\[.+:\s*.+\]$/.test(key)) {
+    return key
+  }
+
   // Check if key ends with '?' (optional marker in TypeScript)
   // If so, process the base key and add '?' back at the end
   const isOptional = key.endsWith('?')