Router Cache entry doesn't work when query params contain %20

[blairmcalpine]

Link to the code that reproduces this issue

https://github.com/blairmcalpine/next-router-cache-bug

To Reproduce

1. Install deps (pnpm i)
2. Start the application with a production build (pnpm build && pnpm start)
3. Load localhost:3000, and then open the network tab in browser devtools.
4. Click "Broken Prefetch", followed by "Broken Push". Notice that there are two RSC network requests, because the initial router cache entry created by the "Broken Prefetch" is missed by the "Broken Push".
5. Go back to localhost:3000/.
6. Click "Working Prefetch", followed by "Working Push". Notice there is correctly just one RSC network request, since the router cache entry creating by "Working Prefetch" is properly read by the "Working Push".

Current vs. Expected behavior

Following the steps above, I expect that clicking "Broken Prefetch" followed by "Broken Push" only creates one network request. Instead, it makes two.

Note that the only different between the working and broken prefetch, is that the broken one encodes a space with %20 (specifically the URL is /other?query=a%20b). The working one uses /other?query=a_b (could be a + as well or any other character), which works.

I believe this issue stems from the fact that the RSC request from the "Broken Prefetch" and "Broken Push" contain a + in the network request instead of a %20. I'd assume this means when the "Broken Push" looks up the cache entry, it uses %20, but the cache entry added by the "Broken Prefetch" contains a +.

I'd assume this can likely be fixed by no longer replacing the %20 in the query parameters with a + when doing the RSC request (which presumably occurs at some point if the query params are parsed into an object and then back to a string using URLSearchParams.toString).

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 23.6.0: Wed Jul 31 20:49:39 PDT 2024; root:xnu-10063.141.1.700.5~1/RELEASE_ARM64_T6000
  Available memory (MB): 32768
  Available CPU cores: 10
Binaries:
  Node: 20.12.0
  npm: 10.5.0
  Yarn: 4.4.0
  pnpm: 9.7.0
Relevant Packages:
  next: 15.0.3 // Latest available version is detected (15.0.3).
  eslint-config-next: 15.0.3
  react: 19.0.0-rc-66855b96-20241106
  react-dom: 19.0.0-rc-66855b96-20241106
  typescript: 5.6.3
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Navigation, Performance, Runtime

Which stage(s) are affected? (Select all that apply)

next start (local), Vercel (Deployed), Other (Deployed)

Additional context

No response