fix(zod-openapi): handle nested app base paths in openapi registration (#955)

* feat: handle nested app base paths in openapi registration

* test: add test for nested base paths in OpenAPI schema

* test(zod-openapi): add route without base path

* chore: add changeset

* chore: format

.changeset/heavy-trains-serve.md

@@ -0,0 +1,5 @@
+---
+'@hono/zod-openapi': patch
+---
+
+fix: use nested app base paths in openapi schema

packages/zod-openapi/src/index.ts

@@ -632,13 +632,23 @@ export class OpenAPIHono<
         case 'route':
           return this.openAPIRegistry.registerPath({
             ...def.route,
-            path: mergePath(pathForOpenAPI, def.route.path),
+            path: mergePath(
+              pathForOpenAPI,
+              // @ts-expect-error _basePath is private
+              app._basePath,
+              def.route.path
+            ),
           })
 
         case 'webhook':
           return this.openAPIRegistry.registerWebhook({
             ...def.webhook,
-            path: mergePath(pathForOpenAPI, def.webhook.path),
+            path: mergePath(
+              pathForOpenAPI,
+              // @ts-expect-error _basePath is private
+              app._basePath,
+              def.webhook.path
+            ),
           })
 
         case 'schema':

packages/zod-openapi/test/index.test.ts

@@ -1156,6 +1156,89 @@ describe('basePath()', () => {
     const data = (await res.json()) as any
     expect(Object.keys(data.paths)[0]).toBe('/api/message')
   })
+
+  it('Should add nested base paths to openapi schema', async () => {
+    const app = new OpenAPIHono()
+
+    const v1 = new OpenAPIHono().basePath('/api/v1')
+    v1.openapi(
+      {
+        method: 'get',
+        path: '/message1',
+        responses: {
+          200: {
+            description: 'Get message',
+            content: {
+              'application/json': {
+                schema: z.object({ message: z.string() }),
+              },
+            },
+          },
+        },
+      },
+      (c) => c.json({ message: 'Hello' })
+    )
+
+    const v2 = new OpenAPIHono().basePath('/api/v2')
+    v2.openapi(
+      {
+        method: 'get',
+        path: '/message2',
+        responses: {
+          200: {
+            description: 'Get message',
+            content: {
+              'application/json': {
+                schema: z.object({ message: z.string() }),
+              },
+            },
+          },
+        },
+      },
+      (c) => c.json({ message: 'Hello' })
+    )
+
+    app.route('/', v1)
+    app.route('/', v2)
+
+    app.openapi(
+      {
+        method: 'get',
+        path: '/hello',
+        responses: {
+          200: {
+            description: 'Get message',
+            content: {
+              'application/json': {
+                schema: z.object({ message: z.string() }),
+              },
+            },
+          },
+        },
+      },
+      (c) => c.json({ message: 'Hello' })
+    )
+
+    const res1 = await app.request('/api/v1/message1')
+    expect(res1.status).toBe(200)
+
+    const res2 = await app.request('/api/v2/message2')
+    expect(res2.status).toBe(200)
+
+    const json = app.getOpenAPIDocument({
+      openapi: '3.0.0',
+      info: {
+        version: '1.0.0',
+        title: 'My API',
+      },
+    })
+
+    const paths = Object.keys(json.paths)
+
+    expect(paths).toStrictEqual(['/api/v1/message1', '/api/v2/message2', '/hello'])
+
+    expect(paths).not.toStrictEqual(['/message1', '/message2', '/hello'])
+  })
 })
 
 describe('With hc', () => {