LibreChat/packages/api
Danny Avila 562bd8ec5f
🐛 fix: Prevent Infinite Render Loop on Code-Execution File Preview (#13922)
* 🐛 fix: Prevent Infinite Render Loop on Code-Execution File Preview

Loading a conversation that contains a large (>1MB) code-execution
office file crashed the whole app with React error #185 ("Maximum
update depth exceeded") on hard refresh.

Root cause (client-only): the terminal-write effect in
useAttachmentPreviewSync writes the resolved preview record back into
messageAttachmentsMap with a fresh object identity on every run, and
`attachment` is in the effect's dependency array. useAttachments
re-derives `attachment` ({...db, ...liveEntry}) with a new identity on
every map write, so once polling resolves (pending -> ready on a loaded
conversation) the effect ping-pongs forever:
setAttachmentsMap -> re-derive -> effect -> setAttachmentsMap.

Only files large/slow enough to defer extraction are persisted at
status: 'pending', which is why small documents never triggered it.

Fix: an idempotency gate that bails before setAttachmentsMap when the
merged attachment already carries the resolved status/text/textFormat/
previewError. The write happens once and then settles.

Tests:
- useAttachmentPreviewSync.loop.spec.tsx wires the real
  useAttachments -> hook feedback to reproduce the loop (verified to
  throw #185 without the gate, settle with it).
- e2e/specs/mock/attachment-preview-loop.spec.ts loads a conversation
  with a pending code-exec attachment whose preview resolves ready and
  asserts the app does not crash.

Closes #13916

* 🔧 feat: Make Office Preview Extraction Cap Configurable (default 2MB)

The inline code-execution preview extraction ceiling was a hardcoded 1MB
constant (MAX_TEXT_EXTRACT_BYTES). Office/text artifacts over that skip
the inline preview and resolve to "Preview unavailable" (download-only).

Make it configurable via FILE_PREVIEW_MAX_EXTRACT_BYTES and raise the
default to 2MB so larger documents get an inline preview out of the box.
The rendered HTML remains independently capped at MAX_TEXT_CACHE_BYTES
(512KB), so image-heavy files over that still fall back to the existing
"preview too large" banner rather than rendering unbounded output.

- resolveMaxTextExtractBytes(env) parses the override, falling back to
  2MB on missing/non-numeric/non-positive values (warns on invalid).
- Documented in .env.example next to the other file-size limits.
- Unit tests cover default, valid override, fractional flooring, and
  invalid fallback.

* 🐛 fix: Guard sub-byte preview cap from flooring to zero

A fractional FILE_PREVIEW_MAX_EXTRACT_BYTES in (0, 1) passed the
positive-number check then floored to 0, making MAX_TEXT_EXTRACT_BYTES
zero and treating every non-empty artifact as oversized. Floor first,
then require the result to be >= 1 byte before accepting it; otherwise
fall back to the 2 MB default. Adds coverage for the sub-byte case.

*  test: Make exported-ceiling assertion env-independent

The "exported ceiling" assertion compared MAX_TEXT_EXTRACT_BYTES to a
literal 2 MB, but that const is initialized from
FILE_PREVIEW_MAX_EXTRACT_BYTES at module load — so the suite would
falsely fail when run with the override set. Assert the export tracks
resolveMaxTextExtractBytes(env) for the current environment instead; the
undefined-case test continues to pin the 2 MB default.
2026-06-23 16:34:43 -04:00
..
src 🐛 fix: Prevent Infinite Render Loop on Code-Execution File Preview (#13922) 2026-06-23 16:34:43 -04:00
types 🔬 ci: Add TypeScript Type Checks to Backend Workflow and Fix All Type Errors (#12451) 2026-03-28 21:06:39 -04:00
.gitignore
babel.config.cjs
jest.config.mjs 📦 chore: npm audit fix (#13828) 2026-06-17 21:54:04 -04:00
jest.setup.cjs 🌱 fix: Inject Code-Tool Files Into Graph Sessions on First Call (+ read_file Sandbox Fallback) (#12831) 2026-04-27 08:56:39 +09:00
package.json 🏷️ chore: Bump Individual Package Versions (#13891) 2026-06-22 09:54:19 -04:00
tsconfig-paths-bootstrap.mjs
tsconfig.build.json
tsconfig.json 📦 chore: npm audit fixes and Mongoose 8.23 TypeScript follow-ups (#12996) 2026-05-07 09:47:40 -04:00
tsconfig.spec.json 📦 chore: Update TypeScript Config for TS v7 (#12794) 2026-04-23 12:51:03 -04:00
tsdown.config.mjs 🪟 fix: Cross-Platform Absolute-Path Check in tsdown neverBundle Predicates (#13700) 2026-06-13 11:04:46 -04:00