s3Storage clientUploads still sends file binary to Server Action, causing 413 error

[du2333]

Describe the Bug

Description

When clientUploads: true is enabled in s3Storage plugin, the initial create request (Next.js Server Action) still includes the full file binary in the multipart form data. This causes a 413 Payload Too Large error due to Next.js's default 1MB limit for Server Actions, defeating the purpose of client-side uploads.

Reproducible Code

// payload.config.ts
plugins: [
    s3Storage({
      collections: {
        media: {
          generateFileURL: ({ filename }) => `${process.env.FRONTEND_URL}/images/${filename}`,
        },
      },
      clientUploads: true,
      bucket: process.env.R2_BUCKET_NAME || '',
      config: {
        credentials: {
          accessKeyId: process.env.R2_ACCESS_KEY_ID || '',
          secretAccessKey: process.env.R2_SECRET_ACCESS_KEY || '',
        },
        region: 'auto',
        endpoint: process.env.R2_ENDPOINT || '',
      },
    }),
  ],

Link to the code that reproduces this issue

https://github.com/du2333/payloadcms-reproduction-repo

Reproduction Steps

1. Enable s3Storage with clientUploads: true.
2. Upload a file larger than 1MB (e.g., 5MB) via the Admin UI.
3. Observe the 413 error in the console.
4. Check the Network tab: the /admin/collections/media/create POST request contains the file binary.

Which area(s) are affected?

plugin: storage-*

Environment Info

Binaries:
  Node: 22.15.0
  npm: 10.9.2
  Yarn: N/A
  pnpm: 10.25.0
Relevant Packages:
  payload: 3.69.0
  next: 15.4.10
  @payloadcms/db-postgres: 3.69.0
  @payloadcms/drizzle: 3.69.0
  @payloadcms/graphql: 3.69.0
  @payloadcms/next/utilities: 3.69.0
  @payloadcms/plugin-cloud-storage: 3.69.0
  @payloadcms/plugin-seo: 3.69.0
  @payloadcms/richtext-lexical: 3.69.0
  @payloadcms/storage-s3: 3.69.0
  @payloadcms/translations: 3.69.0
  @payloadcms/ui/shared: 3.69.0
  react: 19.2.1
  react-dom: 19.2.1
Operating System:
  Platform: linux
  Arch: x64
  Version: #1 SMP Tue Nov 5 00:21:55 UTC 2024
  Available memory (MB): 15951
  Available CPU cores: 16

[timothylp]

Apologies for linking a separate issue here, but they seem to share the same scope. I'm bringing this up again because it's a major blocker that makes clientUploads unusable for my use case.

It's very likely these two issues are interconnected or share a common root cause. I’d really appreciate it if someone could take a look, as my initial report has been stalled for a while now.

Related issue: #12671

[sohamingle]

I traced this back to how the form is wired up with getFormState and its associated Server Action which is used for validation, rendering and permissions.

Because Server Actions are subject to Next.js’ request body size limits (~1 MB by default), this results in a 413 Payload Too Large error for larger files, despite client uploads being enabled.

I’ve prepared a fix that adjusts this flow so the file binary is not passed through the getFormState Server Action.