Turbopack: Move fuzzer for fs watcher into a separate file/module #88666

bgw · 2026-01-16T21:39:01Z

This PR just moves things around for #88667.

I don't care about the code quality here, so this was LLM-generated with very lightweight review.

bgw · 2026-01-16T21:39:19Z

Turbopack: Tweak retry loop for link creation to try to fix os error 80 on Windows #88669
Turbopack: Various cleanup for turbo-tasks-fs, mostly retry logic and string formatting #88668
Turbopack: Add a stress test / fuzzer that tries creating many symlinks in a tight loop #88667
Turbopack: Move fuzzer for fs watcher into a separate file/module #88666 👈 (View in Graphite)
Turbopack: Add file write invalidation tracking to filesystem watcher fuzzing #88665
Turbopack: Extend filesystem watcher fuzzing to cover symlinks and junction points #88192
canary

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codspeed-hq · 2026-01-16T22:03:28Z

CodSpeed Performance Report

Merging this PR will not alter performance

_{Comparing bgw/move-fs-watcher (b17a020) with canary (2912f10)}

Summary

✅ 17 untouched benchmarks
⏩ 3 skipped benchmarks¹

3 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

bgw · 2026-01-20T20:33:36Z

Merge activity

Jan 20, 8:33 PM UTC: A user started a stack merge that includes this pull request via Graphite.
Jan 20, 9:07 PM UTC: Graphite couldn't merge this pull request because a downstack PR Turbopack: Add file write invalidation tracking to filesystem watcher fuzzing #88665 failed to merge.
Jan 21, 6:41 PM UTC: @bgw merged this pull request with Graphite.

nextjs-bot · 2026-01-21T18:32:45Z

Stats from current PR

✅ No significant changes detected

📊 All Metrics

📖 Metrics Glossary

Dev Server Metrics:

Listen = TCP port starts accepting connections
First Request = HTTP server returns successful response
Cold = Fresh build (no cache)
Warm = With cached build artifacts

Build Metrics:

Fresh = Clean build (no .next directory)
Cached = With existing .next directory

Change Thresholds:

Time: Changes < 50ms AND < 10%, OR < 2% are insignificant
Size: Changes < 1KB AND < 1% are insignificant
All other changes are flagged to catch regressions

⚡ Dev Server

Metric	Canary	PR	Change	Trend
Cold (Listen)	456ms	454ms	✓	▁▁▁▁▁
Cold (Ready in log)	441ms	439ms	✓	▇▆▁▇▇
Cold (First Request)	1.166s	1.176s	✓	██▂▇█
Warm (Listen)	456ms	456ms	✓	▁▁▁▁▁
Warm (Ready in log)	443ms	447ms	✓	▁▁▂▁▂
Warm (First Request)	342ms	346ms	✓	▂▁▃▁█

📦 Dev Server (Webpack) (Legacy)

📦 Dev Server (Webpack)

Metric	Canary	PR	Change	Trend
Cold (Listen)	455ms	456ms	✓	▁▅▅▅▅
Cold (Ready in log)	438ms	437ms	✓	▄▇▅▆▁
Cold (First Request)	1.827s	1.826s	✓	▁▃▁▄▂
Warm (Listen)	456ms	457ms	✓	▁▁▁▁▁
Warm (Ready in log)	438ms	438ms	✓	▆▄▂▅▁
Warm (First Request)	1.848s	1.851s	✓	▂▂▁▂▁

⚡ Production Builds

Metric	Canary	PR	Change	Trend
Fresh Build	4.345s	4.299s	✓	▂▂█▂▃
Cached Build	4.351s	4.341s	✓	▂▂█▁▃

📦 Production Builds (Webpack) (Legacy)

📦 Production Builds (Webpack)

Metric	Canary	PR	Change	Trend
Fresh Build	14.082s	14.052s	✓	▁▃▁▃▆
Cached Build	14.169s	14.160s	✓	▁▃▁▂▅
node_modules Size	460 MB	460 MB	✓	█████

📦 Bundle Sizes

Bundle Sizes

⚡ Turbopack

Client

Main Bundles: **432 kB** → **432 kB** ✅ -45 B

82 files with content-based hashes (individual files not comparable between builds)

Server

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	760 B	765 B	✓
Total	760 B	765 B	⚠️ +5 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	451 B	449 B	✓
Total	451 B	449 B	✅ -2 B

📦 Webpack

Client

Main Bundles

	Canary	PR	Change
2086.HASH.js gzip	169 B	N/A	-
2161-HASH.js gzip	5.41 kB	N/A	-
2747-HASH.js gzip	4.48 kB	N/A	-
4322-HASH.js gzip	52.7 kB	N/A	-
ec793fe8-HASH.js gzip	62.3 kB	N/A	-
framework-HASH.js gzip	59.8 kB	59.8 kB	✓
main-app-HASH.js gzip	251 B	254 B	🔴 +3 B (+1%)
main-HASH.js gzip	38.7 kB	39.1 kB	✓
webpack-HASH.js gzip	1.68 kB	1.68 kB	✓
1596.HASH.js gzip	N/A	169 B	-
2658-HASH.js gzip	N/A	52.4 kB	-
6349-HASH.js gzip	N/A	4.46 kB	-
7019-HASH.js gzip	N/A	5.43 kB	-
b17a3386-HASH.js gzip	N/A	62.3 kB	-
Total	226 kB	226 kB	⚠️ +55 B

Polyfills

	Canary	PR	Change
polyfills-HASH.js gzip	39.4 kB	39.4 kB	✓
Total	39.4 kB	39.4 kB	✓

Pages

	Canary	PR	Change
_app-HASH.js gzip	194 B	193 B	✓
_error-HASH.js gzip	182 B	182 B	✓
css-HASH.js gzip	336 B	335 B	✓
dynamic-HASH.js gzip	1.8 kB	1.8 kB	✓
edge-ssr-HASH.js gzip	256 B	256 B	✓
head-HASH.js gzip	352 B	349 B	✓
hooks-HASH.js gzip	385 B	384 B	✓
image-HASH.js gzip	580 B	580 B	✓
index-HASH.js gzip	259 B	258 B	✓
link-HASH.js gzip	2.5 kB	2.51 kB	✓
routerDirect..HASH.js gzip	319 B	317 B	✓
script-HASH.js gzip	385 B	387 B	✓
withRouter-HASH.js gzip	316 B	315 B	✓
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Total	7.97 kB	7.96 kB	✅ -8 B

Server

Edge SSR

	Canary	PR	Change
edge-ssr.js gzip	125 kB	125 kB	✓
page.js gzip	243 kB	238 kB	🟢 4.87 kB (-2%)
Total	368 kB	363 kB	✅ -4.86 kB

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	616 B	619 B	✓
middleware-r..fest.js gzip	155 B	156 B	✓
middleware.js gzip	33 kB	33.2 kB	✓
edge-runtime..pack.js gzip	842 B	842 B	✓
Total	34.7 kB	34.9 kB	⚠️ +193 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	738 B	738 B	✓
Total	738 B	738 B	✓

Build Cache

	Canary	PR	Change
0.pack gzip	3.68 MB	3.69 MB	🔴 +6.5 kB (+0%)
index.pack gzip	101 kB	101 kB	✓
index.pack.old gzip	100 kB	102 kB	🔴 +1.08 kB (+1%)
Total	3.89 MB	3.89 MB	⚠️ +7.37 kB

🔄 Shared (bundler-independent)

Runtimes

	Canary	PR	Change
app-page-exp...dev.js gzip	305 kB	305 kB	✓
app-page-exp..prod.js gzip	162 kB	162 kB	✓
app-page-tur...dev.js gzip	305 kB	305 kB	✓
app-page-tur..prod.js gzip	162 kB	162 kB	✓
app-page-tur...dev.js gzip	302 kB	302 kB	✓
app-page-tur..prod.js gzip	160 kB	160 kB	✓
app-page.run...dev.js gzip	302 kB	302 kB	✓
app-page.run..prod.js gzip	160 kB	160 kB	✓
app-route-ex...dev.js gzip	68.8 kB	68.8 kB	✓
app-route-ex..prod.js gzip	47.6 kB	47.6 kB	✓
app-route-tu...dev.js gzip	68.8 kB	68.8 kB	✓
app-route-tu..prod.js gzip	47.6 kB	47.6 kB	✓
app-route-tu...dev.js gzip	68.4 kB	68.4 kB	✓
app-route-tu..prod.js gzip	47.4 kB	47.4 kB	✓
app-route.ru...dev.js gzip	68.4 kB	68.4 kB	✓
app-route.ru..prod.js gzip	47.4 kB	47.4 kB	✓
dist_client_...dev.js gzip	324 B	324 B	✓
dist_client_...dev.js gzip	326 B	326 B	✓
dist_client_...dev.js gzip	318 B	318 B	✓
dist_client_...dev.js gzip	317 B	317 B	✓
pages-api-tu...dev.js gzip	41.2 kB	41.2 kB	✓
pages-api-tu..prod.js gzip	31.3 kB	31.3 kB	✓
pages-api.ru...dev.js gzip	41.1 kB	41.1 kB	✓
pages-api.ru..prod.js gzip	31.2 kB	31.2 kB	✓
pages-turbo....dev.js gzip	50.8 kB	50.8 kB	✓
pages-turbo...prod.js gzip	38.2 kB	38.2 kB	✓
pages.runtim...dev.js gzip	50.8 kB	50.8 kB	✓
pages.runtim..prod.js gzip	38.2 kB	38.2 kB	✓
server.runti..prod.js gzip	62.2 kB	62.2 kB	✓
Total	2.71 MB	2.71 MB	✅ -2 B

nextjs-bot added created-by: Turbopack team PRs by the Turbopack team. Turbopack Related to Turbopack with Next.js. labels Jan 16, 2026

bgw mentioned this pull request Jan 16, 2026

Turbopack: Extend filesystem watcher fuzzing to cover symlinks and junction points #88192

Merged

bgw requested a review from a team January 16, 2026 22:22

bgw marked this pull request as ready for review January 16, 2026 22:41

lukesandberg approved these changes Jan 20, 2026

View reviewed changes

bgw changed the base branch from bgw/fuzz-track-writes to graphite-base/88666 January 20, 2026 20:34

bgw force-pushed the bgw/move-fs-watcher branch from 79bb768 to fffca45 Compare January 21, 2026 18:09

bgw force-pushed the graphite-base/88666 branch from 8b47431 to 2912f10 Compare January 21, 2026 18:09

graphite-app bot changed the base branch from graphite-base/88666 to canary January 21, 2026 18:10

Turbopack: Move fuzzer for fs watcher into a separate file/module

b17a020

bgw force-pushed the bgw/move-fs-watcher branch from fffca45 to b17a020 Compare January 21, 2026 18:10

bgw merged commit ddd02ab into canary Jan 21, 2026
165 checks passed

bgw deleted the bgw/move-fs-watcher branch January 21, 2026 18:41

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Turbopack: Move fuzzer for fs watcher into a separate file/module #88666

Turbopack: Move fuzzer for fs watcher into a separate file/module #88666

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