Server action resolving to undefined when Vercel throws an error in Next v14

[okcoker]

Link to the code that reproduces this issue

https://github.com/okcoker/vercel-server-action-bug

To Reproduce

1. Visit demo and upload an image larger than the 4.5mb imposed by vercel
2. Vercel will throw a 413 error
3. The server action will resolve with an undefined value

Current vs. Expected behavior

I expect the server action to reject, which seems to be the case in next.js v15

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 23.5.0: Wed May  1 20:17:33 PDT 2024; root:xnu-10063.121.3~5/RELEASE_ARM64_T6031
  Available memory (MB): 49152
  Available CPU cores: 16
Binaries:
  Node: 22.10.0
  npm: 10.9.0
  Yarn: 1.22.21
  pnpm: 9.11.0
Relevant Packages:
  next: 14.2.23 // An outdated version detected (latest is 15.1.4), upgrade is highly recommended!
  eslint-config-next: 14.2.23
  react: 18.3.1
  react-dom: 18.3.1
  typescript: 5.7.3
Next.js Config:
  output: N/A

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

create-next-app, Runtime

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

Vercel (Deployed)

Additional context

Testing with the latest next v15 doesn't seem to have this issue.

[blakewilson]

This is related to #74903. Was fixed via #69945 I believe. Hopefully this can get back ported to Next 14 🙏 cc @samcx

[samcx]

@blakewilson Taking a look!

[ztanner]

Hi @okcoker -- unfortunately we're not able to backport the v15 fix for this, as folks were relying on the behavior of the action promise not being rejected (eg: #71740). To avoid introducing a breaking change, we're not currently planning to backport it to v14.

Please let us know if there's anything blocking you from upgrading to v15.

[okcoker]

@ztanner Thanks for checking into it. I have plans to upgrade to v15 at some point but wanted to do my part in reporting the issue I found in the meantime.