File Upload Error 1570

[SunTheDev]

Description

When a user drag-and-drops a Word document (or any file) that is currently open in another program, the upload
silently fails with a net::ERR_FAILED network error — no feedback is shown to the user. This PR adds a clear error toast to match the existing behavior of the file picker path, which already shows a "This file is in use" message in that scenario.

Changes Made

• packages/playground/src/stores/room/room.store.ts — In the askMessage upload catch block, detect network-level
  upload failures (TypeError: Failed to fetch / net::ERR_FAILED) and show a toast: "This file is in use. Close the
  file in the other program and try again." The toast is raised from the store itself so it fires regardless of
  whether askMessage is awaited or called fire-and-forgot (as it is in the new chat flow).

How to Test

1. Open a .docx file in Microsoft Word (keep it open)
2. In the chat, drag and drop that same file into the "Drop files here to attach to message" drop zone
3. Type any message and hit Send
4. Expected: A toast error appears saying "Uploaded file(s) currently in use by another program. Close the program and re-upload the file(s) in a new chat."
5. Expected (before fix): The baseUpload network call fails silently with net::ERR_FAILED, no error is shown, and
   the file is not recognized by the chat
6. Close the file in Word, repeat steps 2–3
7. Expected: File uploads and is recognized successfully

Notes

• The fix lives entirely in the store so it covers both the new chat flow (new-room-page.tsx calls askMessage
  fire-and-forgot with no .catch()) and the existing room flow (room-content.tsx awaits it)
• The file picker path (Windows Explorer dialog) was already blocking locked files at the OS level before the
  browser received them — this fix brings drag-and-drop to parity with that behavior
• Detection targets TypeError (the JS error class for network failures) and message strings Failed to fetch /
  ERR_FAILED / NetworkError to cover Chrome, Edge, and Firefox variants

[snyk-io]

✅ Snyk checks have passed. No issues have been found so far.

Status	Scan Engine	Critical	High	Medium	Low	Total (0)
✅	Open Source Security	0	0	0	0	0 issues

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[kzsb03]

can we move to support internationalization

[kzsb03]

same as above

[tevanburen]

These won't actually catch the errors we're throwing

[tevanburen]

i don't think we should be using i18n or toast inside the store, i'd prefer to do it in the caller instead

[tevanburen]

no code reads this value