fix(server): update fff to stop runaway watcher rescans

[realhasanshoaib]

Problem

When a project is a big non-git folder that keeps changing, the backend stays at 60–190% CPU even when T3 Code is idle. The file-search library, fff 0.9.4, starts a full rescan of the whole folder after almost any burst of file changes, and nothing limits how often that happens. A burst can be more than 1024 changed paths, an FSEvents rescan flag, or any .gitignore edit. Full details, stack samples and a repro harness are in #14536.

This fixes watcher rescan throttling only. A separate upstream cost remains: binary detection reads changed files to the end (dmtrKovalenko/fff#895).

Change

fff fixed the rescan loop upstream in dmtrKovalenko/fff#751. That change adds a throttle: watcher rescans wait at least 30 seconds, and 5 minutes for non-git roots with 1M or more files. The first release with it is 0.10.3. This PR moves T3 to the current release, 0.11.0.

File	Why
apps/server/package.json, pnpm-lock.yaml	@ff-labs/fff-node 0.9.4 → 0.11.0. The lockfile diff only touches fff packages.
patches/@ff-labs__fff-node@0.11.0.patch, pnpm-workspace.yaml	Moves T3's existing patch to the new version. 0.11.0 ships separate index.cjs and index.js builds. As before, the patch sends require to the ESM build, so the server and its tests share one module instance. It also keeps the app.asar.unpacked native-binary lookup, now in dist/index.js.
scripts/build-desktop-artifact.ts and its test	The Windows native-load probe pointed at dist/src/index.js, which no longer exists. It now points at dist/index.js.

The fff API that T3 calls is unchanged between these versions; 0.11.0 only adds watch(). So there are no server code changes.

Scope and approval

This fixes one problem: runaway rescans in the pinned native dependency. Bug report and evidence: #14536. The PR doesn't touch product behavior, and it's complementary to #11500, which keeps a partial index on scan timeout.

Verification

Problem and fix, measured. I ran a standalone harness with the exact FileFinder.create options from WorkspaceSearchIndex.ts on a real 1.65M-file ~/code folder with live agent activity. It also writes and deletes 1500 files under node_modules every 20 s. Each version ran for about 4 minutes on an Apple M4. The harness is in #14536.

fff-node	full scans	CPU used	average load
0.9.4	7 in 240 s	191 s	80% of a core
0.11.0	4 in 291 s	137 s	47% of a core (−41%)

Readiness refresh (2026-10-02): merged current main 54084ae1e into the existing PR branch, preserving the current Expo patches when resolving the lockfile/workspace conflicts. The PR still changes only the seven files above. The update is a normal fast-forward from the existing head; no history rewrite is needed.

Checks on refreshed head dcff125e3, run on a separate Apple M4 test host with Node 24.13.1 / pnpm 11.10.0:

• Frozen-lockfile installation: passed.
• Workspace and desktop-artifact tests: 137 passed across 5 files (62 workspace + 75 artifact tests).
• Server and scripts tsc --noEmit: passed; existing Effect suggestions only.
• Targeted lint for the artifact script and test: 0 warnings, 0 errors.
• One scoped Codex CLI review (GPT-6.1-Sol, high reasoning): no actionable regressions. The reviewer also checked native loading, shared require/import identity, index warmup and search. After main advanced, the same scoped change was retained and the focused checks were re-run.

Packaged Electron native-load evidence: an isolated minimal macOS arm64 fixture used Electron 44.4.2 and the exact patched fff-node package/dependency closure from this lockfile. It ran from an actual app.asar with native .node / .dylib files unpacked. The fixture asserted packaged-app mode, shared require/import identity, an .asar.unpacked native-library path, successful index creation and the expected file-search result.

{"electron":"44.4.2","node":"24.21.0","isPackaged":true,"binary":"<fixture>.app/Contents/Resources/app.asar.unpacked/node_modules/@ff-labs/fff-bin-darwin-arm64/libfff_c.dylib","indexedFiles":1,"result":"needle.ts"}

Limits: this was a minimal packaged Electron native-load smoke test, not a complete T3 installer build. Packaged Windows/Linux execution and full desktop workflows were not tested. The existing Windows probe unit tests passed. The benchmark above consists of sequential runs on a changing live workspace, not a controlled claim about all projects or total app memory.

Readiness refresh performed with Codex (GPT-6); scoped CLI review used GPT-6.1-Sol at high reasoning.

Built with Claude Opus 5.5 (1M context) in T3 Code through the Claude Code harness, at medium reasoning effort.

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[macroscopeapp]

Approvability

Verdict: Approved at 58a8f4c

Macroscope's review found this PR approvable — This is a focused fff-node dependency bug fix that throttles runaway watcher rescans while preserving the existing search integration and native packaging behavior. The remaining changes are lockfile, patch-layout, and packaging-probe updates rather than new product capability or broad infrastructure changes.

No code changes detected at c09c710. Prior analysis still applies.

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📥 Commits

Reviewing files that changed from the base of the PR and between c09c710 and dcff125.

⛔ Files ignored due to path filters (1)

• pnpm-lock.yaml is excluded by !**/pnpm-lock.yaml

📒 Files selected for processing (1)

• pnpm-workspace.yaml

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📝 Walkthrough

Walkthrough

The server dependency and workspace patch move to fff-node 0.11.0. The patch updates its require export target and ASAR binary-path resolution. The Windows native-load probe and its test use the package’s updated entry point.

Changes

fff-node dependency and packaging

Layer / File(s)	Summary
Upgrade fff-node and update its patch apps/server/package.json, pnpm-workspace.yaml, patches/@ff-labs__fff-node@0.9.4.patch, patches/@ff-labs__fff-node@0.11.0.patch	The dependency and patch mapping move to version 0.11.0, and the previous version’s patch is removed. The new patch points the require export to dist/index.js and uses an existing .asar.unpacked path when available, otherwise retaining the original binary path.
Update the Windows native-load probe scripts/build-desktop-artifact.ts, scripts/build-desktop-artifact.test.ts	The Windows probe and its test now use dist/index.js instead of dist/src/index.js.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Suggested reviewers: juliusmarminge

Merge Risk: ⚪ Minimal · up to dcff1

The dependency mapping and Windows probe follow the updated entry path. Although the 0.11.0 archive was unavailable for independent inspection, no actionable mismatch or merge blocker is established.

Architecture Summary

Architecture risk: 🔵 Low · up to dcff1

The change affects 4 systems.

Changed systems: patches, scripts, apps/server, pnpm-workspace.yaml

Architecture concerns
No architecture-level concerns identified.

Review details

Systems and components

• observed — patches (service) was modified; 2 changed files map to changed impact.
• observed — scripts (service) was modified; 2 changed files map to changed impact.
• observed — apps/server (service) was modified; 1 changed file maps to changed impact.
• observed — pnpm-workspace.yaml (service) was modified; 1 changed file maps to changed impact.

Before / after behavior

• observed — Modified behavior in apps/server/package.json: The @ff-labs/fff-node dependency version changes from 0.9.4 to 0.11.0.
• observed — Modified behavior in patches/@ff-labs__fff-node@0.11.0.patch: The package’s require export changes from dist/index.cjs to dist/index.js.
• observed — Modified behavior in patches/@ff-labs__fff-node@0.11.0.patch: dist/index.js adds the sep path import needed to split and rejoin paths using the platform separator.
• observed — Modified behavior in patches/@ff-labs__fff-node@0.11.0.patch: Adds resolveUnpackedAsarPath: it finds the last path segment ending in .asar, returns the original path if none exists, and otherwise uses the corresponding .asar.unpacked path only when that path exists.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 2…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly identifies the dependency update and its purpose: stopping runaway watcher rescans in the server.
Description check	✅ Passed	The description includes complete Problem, Change, Scope and approval, and Verification sections. It explains the issue, implementation, scope, test results, benchmark limits, and untested areas.

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