fix: allow v2 functions to serve /favicon.ico (#6145)

* fix: allow v2 functions to serve /favicon.ico

* fix: remove favicon handling

src/lib/functions/server.mjs

@@ -233,10 +233,6 @@ const getFunctionsServer = (options) => {
     }),
   )
 
-  app.get('/favicon.ico', function onRequest(_req, res) {
-    res.status(204).end()
-  })
-
   app.all(`${functionsPrefix}*`, functionHandler)
   app.all(`${buildersPrefix}*`, functionHandler)
 

tests/integration/__fixtures__/dev-server-with-v2-functions/functions/favicon.mjs

@@ -0,0 +1,6 @@
+export default () => new Response(`custom-generated favicon`)
+
+export const config = {
+  path: '/favicon.ico',
+  method: 'GET',
+}

tests/integration/commands/dev/v2-api.test.ts

@@ -152,6 +152,12 @@ describe.runIf(gte(version, '18.13.0'))('v2 api', () => {
       expect(await response.text()).toBe(`Catchall Path`)
     })
 
+    test<FixtureTestContext>('functions can also run on /favicon.ico', async ({ devServer }) => {
+      const response = await fetch(`http://localhost:${devServer.port}/favicon.ico`)
+      expect(response.status).toBe(200)
+      expect(await response.text()).toBe('custom-generated favicon')
+    })
+
     test<FixtureTestContext>('returns 404 when using the default function URL to access a function with custom routes', async ({
       devServer,
     }) => {