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Trace upload: include experimental flag states#89845

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wbinnssmith merged 5 commits into
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wbinnssmith/trace-exp-flags
Feb 12, 2026
Merged

Trace upload: include experimental flag states#89845
wbinnssmith merged 5 commits into
canaryfrom
wbinnssmith/trace-exp-flags

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This includes the set of experimental flag states in events sent to the trace upload receiver when --experimental-trace-upload is set. It only includes a subset of experimental flags (so things like the trace upload flag itself isn't meaninglessly sent).

Since reporting is often limited to the scope of a single span, the flag state attributes are denormalized and copied onto every descendent span. Limiting the set of flags prevents this from being unnecessarily large.

Test Plan: Added test/development test and built an app and verified these tags are sent with NEXT_TRACE_UPLOAD_DEBUG

This includes the set of experimental flag states in events sent to the trace upload receiver when `--experimental-trace-upload` is set. It only includes a subset of experimental flags (so things like the trace upload flag itself isn't meaninglessly sent).

Since reporting is often limited to the scope of a single span, the flag state attributes are denormalized and copied onto every descendent span.  Limiting the set of flags prevents this from being unnecessarily large.

Test Plan: Added `test/development` test and built an app and verified these tags are sent with `NEXT_TRACE_UPLOAD_DEBUG`
@wbinnssmith wbinnssmith marked this pull request as ready for review February 11, 2026 18:57
Comment thread packages/next/src/cli/next-dev.ts Outdated
Co-authored-by: vercel[bot] <35613825+vercel[bot]@users.noreply.github.com>
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Stats from current PR

🟢 1 improvement

Metric Canary PR Change Trend
node_modules Size 472 MB 467 MB 🟢 4.91 MB (-1%) █████
📊 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) 455ms 456ms ▁▁▁▁▁
Cold (Ready in log) 445ms 445ms ▂▁▂▂▂
Cold (First Request) 840ms 817ms ▅▁▄▄▄
Warm (Listen) 456ms 457ms ▁▁▁▁▁
Warm (Ready in log) 444ms 444ms ▁▁▁▁▁
Warm (First Request) 346ms 342ms ▁▁▁▁▁
📦 Dev Server (Webpack) (Legacy)

📦 Dev Server (Webpack)

Metric Canary PR Change Trend
Cold (Listen) 455ms 456ms ▁▁█▁▁
Cold (Ready in log) 439ms 439ms ▃▁█▅▂
Cold (First Request) 1.845s 1.849s ▂▁█▃▁
Warm (Listen) 456ms 456ms ▁▁█▁▁
Warm (Ready in log) 438ms 441ms ▃▁█▄▁
Warm (First Request) 1.852s 1.879s ▂▁█▃▁

⚡ Production Builds

Metric Canary PR Change Trend
Fresh Build 4.050s 3.994s ▁▂▁▁▁
Cached Build 4.085s 4.028s ▁▂▁▁▁
📦 Production Builds (Webpack) (Legacy)

📦 Production Builds (Webpack)

Metric Canary PR Change Trend
Fresh Build 13.897s 13.888s ▁▁█▂▁
Cached Build 13.968s 13.995s ▁▁█▂▁
node_modules Size 472 MB 467 MB 🟢 4.91 MB (-1%) █████
📦 Bundle Sizes

Bundle Sizes

⚡ Turbopack

Client

Main Bundles: **437 kB** → **437 kB** ✅ -10 B

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

Server

Middleware
Canary PR Change
middleware-b..fest.js gzip 761 B 756 B
Total 761 B 756 B ✅ -5 B
Build Details
Build Manifests
Canary PR Change
_buildManifest.js gzip 449 B 449 B
Total 449 B 449 B

📦 Webpack

Client

Main Bundles
Canary PR Change
5528-HASH.js gzip 5.47 kB N/A -
6280-HASH.js gzip 57 kB N/A -
6335.HASH.js gzip 169 B N/A -
912-HASH.js gzip 4.53 kB N/A -
e8aec2e4-HASH.js gzip 62.5 kB N/A -
framework-HASH.js gzip 59.7 kB 59.7 kB
main-app-HASH.js gzip 256 B 254 B
main-HASH.js gzip 39.1 kB 39.1 kB
webpack-HASH.js gzip 1.68 kB 1.68 kB
262-HASH.js gzip N/A 4.53 kB -
2889.HASH.js gzip N/A 169 B -
5602-HASH.js gzip N/A 5.49 kB -
6948ada0-HASH.js gzip N/A 62.5 kB -
9544-HASH.js gzip N/A 57.7 kB -
Total 230 kB 231 kB ⚠️ +636 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 194 B
_error-HASH.js gzip 183 B 180 B 🟢 3 B (-2%)
css-HASH.js gzip 331 B 330 B
dynamic-HASH.js gzip 1.81 kB 1.81 kB
edge-ssr-HASH.js gzip 256 B 256 B
head-HASH.js gzip 351 B 352 B
hooks-HASH.js gzip 384 B 383 B
image-HASH.js gzip 580 B 581 B
index-HASH.js gzip 260 B 260 B
link-HASH.js gzip 2.49 kB 2.49 kB
routerDirect..HASH.js gzip 320 B 319 B
script-HASH.js gzip 386 B 386 B
withRouter-HASH.js gzip 315 B 315 B
1afbb74e6ecf..834.css gzip 106 B 106 B
Total 7.97 kB 7.97 kB ✅ -1 B

Server

Edge SSR
Canary PR Change
edge-ssr.js gzip 126 kB 126 kB
page.js gzip 249 kB 250 kB
Total 375 kB 376 kB ⚠️ +312 B
Middleware
Canary PR Change
middleware-b..fest.js gzip 616 B 615 B
middleware-r..fest.js gzip 156 B 155 B
middleware.js gzip 33.1 kB 33.2 kB
edge-runtime..pack.js gzip 842 B 842 B
Total 34.7 kB 34.8 kB ⚠️ +71 B
Build Details
Build Manifests
Canary PR Change
_buildManifest.js gzip 733 B 735 B
Total 733 B 735 B ⚠️ +2 B
Build Cache
Canary PR Change
0.pack gzip 3.84 MB 3.85 MB 🔴 +9.46 kB (+0%)
index.pack gzip 104 kB 103 kB
index.pack.old gzip 102 kB 103 kB
Total 4.05 MB 4.05 MB ⚠️ +9.24 kB

🔄 Shared (bundler-independent)

Runtimes
Canary PR Change
app-page-exp...dev.js gzip 316 kB 316 kB
app-page-exp..prod.js gzip 168 kB 168 kB
app-page-tur...dev.js gzip 315 kB 315 kB
app-page-tur..prod.js gzip 167 kB 167 kB
app-page-tur...dev.js gzip 312 kB 312 kB
app-page-tur..prod.js gzip 166 kB 166 kB
app-page.run...dev.js gzip 312 kB 312 kB
app-page.run..prod.js gzip 166 kB 166 kB
app-route-ex...dev.js gzip 70.5 kB 70.5 kB
app-route-ex..prod.js gzip 49 kB 49 kB
app-route-tu...dev.js gzip 70.5 kB 70.5 kB
app-route-tu..prod.js gzip 49 kB 49 kB
app-route-tu...dev.js gzip 70.1 kB 70.1 kB
app-route-tu..prod.js gzip 48.8 kB 48.8 kB
app-route.ru...dev.js gzip 70.1 kB 70.1 kB
app-route.ru..prod.js gzip 48.8 kB 48.8 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 43.2 kB 43.2 kB
pages-api-tu..prod.js gzip 32.9 kB 32.9 kB
pages-api.ru...dev.js gzip 43.2 kB 43.2 kB
pages-api.ru..prod.js gzip 32.8 kB 32.8 kB
pages-turbo....dev.js gzip 52.5 kB 52.5 kB
pages-turbo...prod.js gzip 39.4 kB 39.4 kB
pages.runtim...dev.js gzip 52.5 kB 52.5 kB
pages.runtim..prod.js gzip 39.4 kB 39.4 kB
server.runti..prod.js gzip 62.7 kB 62.7 kB
Total 2.8 MB 2.8 MB ✅ -377 B
📝 Changed Files (17 files)

Files with changes:

  • app-page-exp..ntime.dev.js
  • app-page-exp..time.prod.js
  • app-page-tur..ntime.dev.js
  • app-page-tur..time.prod.js
  • app-page-tur..ntime.dev.js
  • app-page-tur..time.prod.js
  • app-page.runtime.dev.js
  • app-page.runtime.prod.js
  • app-route-ex..ntime.dev.js
  • app-route-ex..time.prod.js
  • app-route-tu..ntime.dev.js
  • app-route-tu..time.prod.js
  • app-route-tu..ntime.dev.js
  • app-route-tu..time.prod.js
  • app-route.runtime.dev.js
  • app-route.ru..time.prod.js
  • server.runtime.prod.js
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@wbinnssmith wbinnssmith force-pushed the wbinnssmith/trace-exp-flags branch from 2a02a5e to a2ab41c Compare February 12, 2026 00:30
Comment thread packages/next/src/cli/next-dev.ts Outdated
Comment thread packages/next/src/server/lib/start-server.ts Outdated
Comment thread packages/next/src/trace/trace-uploader.ts Outdated
Comment thread test/development/app-dir/experimental-flags-trace/next.config.js Outdated
Comment thread packages/next/src/trace/trace-uploader.ts Outdated
Co-authored-by: Luke Sandberg <lukesandberg@users.noreply.github.com>
Comment thread packages/next/src/cli/next-dev.ts Outdated
@wbinnssmith wbinnssmith force-pushed the wbinnssmith/trace-exp-flags branch 3 times, most recently from 7190b37 to 9011716 Compare February 12, 2026 07:27
@wbinnssmith wbinnssmith force-pushed the wbinnssmith/trace-exp-flags branch from 9011716 to d11bb67 Compare February 12, 2026 17:59
@wbinnssmith wbinnssmith force-pushed the wbinnssmith/trace-exp-flags branch from d11bb67 to 6869c92 Compare February 12, 2026 19:30
@wbinnssmith wbinnssmith merged commit b3774ea into canary Feb 12, 2026
289 of 291 checks passed
@wbinnssmith wbinnssmith deleted the wbinnssmith/trace-exp-flags branch February 12, 2026 20:47
@github-actions github-actions Bot locked as resolved and limited conversation to collaborators Feb 27, 2026
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