[BUG] SearchParams with the same key are not parsed into a string array

[ilovemesomeramen]

Describe the bug

NextJs supports multiple search params with the same key which are parsed into a string array, e.g.

?foo=bar&foo=bar2 = {foo: ['bar', 'bar2']}

in the opennext runtime following query parameters will result in

?foo=bar&foo=bar2 = {foo: 'bar2'}

Steps to reproduce

Create a new Page:

export default async function Page({
  searchParams,
}: {
  searchParams: Promise<{ [key: string]: string | string[] }>;
}) {
  const sParams = await searchParams;

  return (
    <div>
      {Object.entries(sParams).map(([k, v]) => {
        return <p>{`${k}: ${v}`}</p>;
      })}
    </div>
  );
}

go to the page with the same query key twice in the URL such as ?foo=bar&foo=bar2 once in the normal next server and once using wrangler and you will see the difference

Expected behavior

multiple query parameters of with the same key should be parsed into a string array as well.

@opennextjs/cloudflare version

1.0.0-beta.0

Wrangler version

4.7.2

next info output

Operating System:
  Platform: linux
  Arch: x64
  Version: #1 SMP PREEMPT_DYNAMIC Mon, 24 Mar 2025 06:33:36 +0000
  Available memory (MB): 63483
  Available CPU cores: 16
Binaries:
  Node: 20.11.1
  npm: 10.2.4
  Yarn: N/A
  pnpm: 10.7.0
Relevant Packages:
  next: 15.2.4 // Latest available version is detected (15.2.4).
  eslint-config-next: 15.2.4
  react: 19.1.0
  react-dom: 19.1.0
  typescript: 5.7.2
Next.js Config:
  output: N/A

Additional context

No response

[vicb]

I can not reproduce with 1.0.0-beta.0.
If you still have the error, please paste a link to a minimal repro in a GH repository

[ilovemesomeramen]

@vicb Here you can find a minimal reproducible example.
After further digging it appears to be related to the next-intl middleware which appears to be treated differently in when being compiled with wrangler.

removing the intlMiddleware call in the middleware makes it work.

tested with v3 and v4 of next-intl the issue remains

[vicb]

@ilovemesomeramen could you please check the latest release 1.0.0-beta.3 works for you?

[ilovemesomeramen]

the issue still remains.

I updated the min example with the new version

[vicb]

@conico974 I traced it down to https://github.com/opennextjs/opennextjs-aws/blob/main/packages/open-next/src/core/routing/middleware.ts#L147-L165

The foreach as the bottom can be called multiple time with the same key, overwriting the previous value.

Should I investigate more or do you want to take over?