Fix React channel env missing in custom server

[shuding]

Fixes #48948 (repro). When running inside a custom server with app dir, we should always opt into the prebundled React with correct channels.

Thanks @karlhorky for help testing it!

Fixes #49169 too.

[ijjk]

Failing test suites

Commit: 0bba771

pnpm testheadless test/e2e/app-dir/navigation/navigation.test.ts

• app dir - navigation > redirect > components > should redirect to external url, initiating only once

Expand output

● app dir - navigation › redirect › components › should redirect to external url, initiating only once

expect(received).toEqual(expected) // deep equality

- Expected  - 1
+ Received  + 1

  Object {
-   "navigate-https://example.vercel.sh/": "1",
+   "navigate-https://example.vercel.sh/": "2",
    "navigation-supported": "true",
  }

  184 |           }
  185 |
> 186 |           expect(stored).toEqual({
      |                          ^
  187 |             'navigate-https://example.vercel.sh/': '1',
  188 |             'navigation-supported': 'true',
  189 |           })

  at Object.<anonymous> (e2e/app-dir/navigation/navigation.test.ts:186:26)

Read more about building and testing Next.js in contributing.md.

[sophiebits]

(You wrote "Fixes #49168" but that's a link to this PR.)

[shuding]

Thanks @sophiebits, fixed. My clipboard is too slow.

[shuding]

The failing test is strange, can't reproduce it locally with both dev and prod. Will take a look later.

[shuding]

@sophiebits I saw your comments

// Not actually sure why this is '2' in dev. Possibly something
// related to an update triggered by <HotReload>?
'navigate-https://example.vercel.sh/': isNextDev ? '2' : '1',

and it's now always '1' with this change so tests are failing (I haven't looked into it), and hopefully that's not a bad thing? Can I just update the test?

This is interesting as I guess there might be some tests accidentally using the custom server mode and causes some inconsistency.

[sophiebits]

sure! seems fine

[karlhorky]

I can confirm next@13.3.5-canary.8 (first version including PR #49168) is working with custom servers 🎉 Thanks @shuding !!

CodeSandbox: https://codesandbox.io/p/sandbox/quirky-bell-o5tl8l?file=%2Fserver.mjs