fix: file objects being serialized to plain objects in upload form state

[PatrikKozak]

What?

Fixes a bug where saving an upload document would fail with "[object Object]" is not valid JSON error after changing the file and then modifying another field.

Why?

When a file was changed in an upload document and saved, the File object would persist in the client-side form state.

On the next save (when modifying a different field), the form state would be deep copied and serialized before submission. This serialization converted the File object into a plain object {name, size, type, ...}, which was then stringified to "[object Object]" and sent to the server, causing a JSON parsing error.

How?

1. Preserve File objects during serialization

   • Added instanceof File check in deepCopyObjectSimpleWithoutReactComponents to return File objects as-is instead of serializing them to plain objects
   • Similar to how Date objects are already handled

2. Clear file field after successful save

   • Delete the file field from form state after save in upload collections
   • Prevents stale File objects from persisting between saves

I could of just added an instanceof File check in createFormData but it would be just a bandaid fix. If a non-File object reaches that code, it indicates a bug elsewhere that should fail loudly. The root causes were:

• File objects being incorrectly serialized during form submission
• File objects persisting in form state after they should be cleared

Fixes #14814

[github-actions]

📦 esbuild Bundle Analysis for payload

This analysis was generated by esbuild-bundle-analyzer. 🤖

Meta File	Out File	Size (raw)	Note
packages/next/meta_index.json	esbuild/index.js	810.16 KB	✅ No change
packages/payload/meta_index.json	esbuild/index.js	1.23 MB	✅ No change
packages/payload/meta_shared.json	esbuild/exports/shared.js	164.15 KB	⚠️ +30 B (+0.0%)
packages/richtext-lexical/meta_client.json	esbuild/exports/client_optimized/index.js	281.03 KB	✅ No change
packages/ui/meta_client.json	esbuild/exports/client_optimized/index.js	1.16 MB	⚠️ +23 B (+0.0%)
packages/ui/meta_shared.json	esbuild/exports/shared_optimized/index.js	14.39 KB	✅ No change

Largest paths

These visualization shows top 20 largest paths in the bundle.

Meta file: packages/next/meta_index.json, Out file: esbuild/index.js

Path	Size
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dist/views/API	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 6.01 KB
dist/views/Versions	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 5.96 KB
dist/elements/Nav	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 5.53 KB
dist/views/Account	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 5.32 KB
dist/elements/DocumentHeader	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 4.81 KB
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dist/views/ForgotPassword	${{\color{Goldenrod}{ }}}$ 0.4%, 3.09 KB
dist/layouts/Root	${{\color{Goldenrod}{ }}}$ 0.4%, 2.91 KB
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dist/views/CollectionFolders	${{\color{Goldenrod}{ }}}$ 0.3%, 2.46 KB
dist/views/ResetPassword	${{\color{Goldenrod}{ }}}$ 0.3%, 2.41 KB
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(other)	${{\color{Goldenrod}{ ████▋ }}}$ 18.7%, 150.79 KB

Meta file: packages/payload/meta_index.json, Out file: esbuild/index.js

Path	Size
../../node_modules	${{\color{Goldenrod}{ █████████████████▏ }}}$ 68.7%, 841.11 KB
dist/fields/hooks	${{\color{Goldenrod}{ ▉ }}}$ 3.5%, 43.31 KB
dist/collections/operations	${{\color{Goldenrod}{ ▊ }}}$ 3.0%, 36.40 KB
dist/auth/operations	${{\color{Goldenrod}{ ▎ }}}$ 1.2%, 15.23 KB
dist/queues/operations	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 12.11 KB
dist/globals/operations	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 11.98 KB
dist/fields/config	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 11.95 KB
dist/utilities/configToJSONSchema.js	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 11.83 KB
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dist/database/migrations	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 8.07 KB
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dist/uploads/fetchAPI-multipart	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 7.74 KB
dist/index.js	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 7.59 KB
dist/config/orderable	${{\color{Goldenrod}{ ▏ }}}$ 0.5%, 6.27 KB
dist/collections/endpoints	${{\color{Goldenrod}{ ▏ }}}$ 0.5%, 6.00 KB
dist/auth/strategies	${{\color{Goldenrod}{ }}}$ 0.4%, 5.50 KB
dist/config/sanitize.js	${{\color{Goldenrod}{ }}}$ 0.4%, 5.49 KB
dist/auth/endpoints	${{\color{Goldenrod}{ }}}$ 0.4%, 5.42 KB
dist/utilities/telemetry	${{\color{Goldenrod}{ }}}$ 0.4%, 5.31 KB
(other)	${{\color{Goldenrod}{ ███████▊ }}}$ 31.3%, 382.87 KB

Meta file: packages/payload/meta_shared.json, Out file: esbuild/exports/shared.js

Path	Size
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dist/fields/validations.js	${{\color{Goldenrod}{ █▌ }}}$ 6.4%, 10.21 KB
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dist/utilities/deepCopyObject.js	${{\color{Goldenrod}{ ▍ }}}$ 1.6%, 2.51 KB
dist/auth/cookies.js	${{\color{Goldenrod}{ ▎ }}}$ 1.0%, 1.55 KB
dist/utilities/flattenTopLevelFields.js	${{\color{Goldenrod}{ ▏ }}}$ 0.9%, 1.42 KB
dist/fields/config	${{\color{Goldenrod}{ ▏ }}}$ 0.8%, 1.28 KB
dist/utilities/flattenAllFields.js	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 943 B
dist/folders/utils	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 916 B
dist/utilities/getVersionsConfig.js	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 895 B
dist/utilities/unflatten.js	${{\color{Goldenrod}{ ▏ }}}$ 0.5%, 779 B
dist/utilities/sanitizeUserDataForEmail.js	${{\color{Goldenrod}{ }}}$ 0.4%, 713 B
dist/utilities/getFieldPermissions.js	${{\color{Goldenrod}{ }}}$ 0.4%, 651 B
dist/collections/config	${{\color{Goldenrod}{ }}}$ 0.4%, 570 B
dist/bin/generateImportMap	${{\color{Goldenrod}{ }}}$ 0.3%, 561 B
dist/auth/sessions.js	${{\color{Goldenrod}{ }}}$ 0.3%, 525 B
dist/utilities/getSafeRedirect.js	${{\color{Goldenrod}{ }}}$ 0.3%, 423 B
dist/utilities/deepMerge.js	${{\color{Goldenrod}{ }}}$ 0.3%, 413 B
dist/utilities/formatLabels.js	${{\color{Goldenrod}{ }}}$ 0.2%, 380 B
dist/utilities/appendUploadSelectFields.js	${{\color{Goldenrod}{ }}}$ 0.2%, 360 B
(other)	${{\color{Goldenrod}{ █████▎ }}}$ 21.0%, 33.72 KB

Meta file: packages/richtext-lexical/meta_client.json, Out file: esbuild/exports/client_optimized/index.js

Path	Size
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dist/lexical/plugins	${{\color{Goldenrod}{ ██▉ }}}$ 11.5%, 32.00 KB
dist/lexical/ui	${{\color{Goldenrod}{ ██▏ }}}$ 8.8%, 24.36 KB
dist/features/experimental_table	${{\color{Goldenrod}{ ██▏ }}}$ 8.5%, 23.70 KB
dist/packages/@lexical	${{\color{Goldenrod}{ █▋ }}}$ 6.8%, 18.99 KB
dist/features/link	${{\color{Goldenrod}{ █▋ }}}$ 6.5%, 18.04 KB
dist/features/toolbars	${{\color{Goldenrod}{ █▌ }}}$ 6.4%, 17.75 KB
dist/features/upload	${{\color{Goldenrod}{ █▏ }}}$ 4.9%, 13.73 KB
dist/features/textState	${{\color{Goldenrod}{ █ }}}$ 4.0%, 11.08 KB
dist/features/relationship	${{\color{Goldenrod}{ ▊ }}}$ 3.2%, 8.96 KB
dist/lexical/utils	${{\color{Goldenrod}{ ▊ }}}$ 3.0%, 8.22 KB
dist/features/debug	${{\color{Goldenrod}{ ▋ }}}$ 2.7%, 7.39 KB
dist/utilities/fieldsDrawer	${{\color{Goldenrod}{ ▋ }}}$ 2.6%, 7.12 KB
dist/features/converters	${{\color{Goldenrod}{ ▋ }}}$ 2.5%, 7.04 KB
dist/lexical/config	${{\color{Goldenrod}{ ▍ }}}$ 1.8%, 5.08 KB
dist/features/lists	${{\color{Goldenrod}{ ▍ }}}$ 1.8%, 5.00 KB
dist/features/format	${{\color{Goldenrod}{ ▎ }}}$ 1.2%, 3.46 KB
dist/lexical/LexicalEditor.js	${{\color{Goldenrod}{ ▎ }}}$ 1.1%, 3.17 KB
dist/lexical/theme	${{\color{Goldenrod}{ ▏ }}}$ 0.9%, 2.62 KB
dist/features/indent	${{\color{Goldenrod}{ ▏ }}}$ 0.9%, 2.50 KB
(other)	${{\color{Goldenrod}{ █████████████████████▊ }}}$ 87.4%, 242.76 KB

Meta file: packages/ui/meta_client.json, Out file: esbuild/exports/client_optimized/index.js

Path	Size
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dist/elements/FolderView	${{\color{Goldenrod}{ ▋ }}}$ 2.5%, 29.18 KB
dist/elements/BulkUpload	${{\color{Goldenrod}{ ▌ }}}$ 2.4%, 27.14 KB
dist/elements/WhereBuilder	${{\color{Goldenrod}{ ▍ }}}$ 1.5%, 16.85 KB
dist/views/Edit	${{\color{Goldenrod}{ ▎ }}}$ 1.4%, 16.03 KB
dist/fields/Relationship	${{\color{Goldenrod}{ ▎ }}}$ 1.4%, 15.75 KB
dist/elements/Table	${{\color{Goldenrod}{ ▎ }}}$ 1.3%, 15.46 KB
dist/forms/Form	${{\color{Goldenrod}{ ▎ }}}$ 1.3%, 15.08 KB
dist/fields/Upload	${{\color{Goldenrod}{ ▎ }}}$ 1.2%, 14.06 KB
dist/fields/Blocks	${{\color{Goldenrod}{ ▎ }}}$ 1.2%, 13.70 KB
dist/elements/PublishButton	${{\color{Goldenrod}{ ▏ }}}$ 0.8%, 8.68 KB
dist/elements/QueryPresets	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 8.58 KB
dist/providers/Folders	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 8.49 KB
dist/elements/LivePreview	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 8.38 KB
dist/elements/ListHeader	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 7.83 KB
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dist/fields/Array	${{\color{Goldenrod}{ ▏ }}}$ 0.7%, 7.55 KB
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Meta file: packages/ui/meta_shared.json, Out file: esbuild/exports/shared_optimized/index.js

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dist/utilities/handleTakeOver.js	${{\color{Goldenrod}{ ▊ }}}$ 3.2%, 440 B
dist/elements/withMergedProps	${{\color{Goldenrod}{ ▋ }}}$ 2.5%, 339 B
dist/elements/WithServerSideProps	${{\color{Goldenrod}{ ▍ }}}$ 1.7%, 232 B
dist/utilities/handleGoBack.js	${{\color{Goldenrod}{ ▎ }}}$ 1.2%, 168 B
dist/fields/mergeFieldStyles.js	${{\color{Goldenrod}{ ▎ }}}$ 1.2%, 159 B
dist/forms/Form	${{\color{Goldenrod}{ ▎ }}}$ 1.1%, 147 B
dist/utilities/abortAndIgnore.js	${{\color{Goldenrod}{ ▎ }}}$ 1.1%, 146 B
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dist/utilities/findLocaleFromCode.js	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 84 B
dist/utilities/sanitizeID.js	${{\color{Goldenrod}{ ▏ }}}$ 0.6%, 77 B
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(other)	${{\color{Goldenrod}{ ███████████████████▎ }}}$ 77.4%, 10.68 KB

Details

Next to the size is how much the size has increased or decreased compared with the base branch of this PR.

• ‼️: Size increased by 20% or more. Special attention should be given to this.
• ⚠️: Size increased in acceptable range (lower than 20%).
• ✅: No change or even downsized.
• 🗑️: The out file is deleted: not found in base branch.
• 🆕: The out file is newly found: will be added to base branch.

[isakstarlander]

Sweet! Nice work. Thank you for looking into it this quickly! 🌟