[turbopack] Followup for `#[derive(ValueToString)]` by mmastrac · Pull Request #89936 · vercel/next.js

mmastrac · 2026-02-13T03:23:06Z

What

Follow-up to #89788, addressing review feedback from @lukesandberg.

Why

Several small issues were flagged during review that didn't block merge but should be cleaned up.

How

Remove is_pure_constant: Instead of checking whether a format string contains braces, unescape {{/}} at macro expansion time so rcstr! works for all constant format strings (no runtime format! needed)
require_context.rs: Replace awkward inline if expression in #[value_to_string(...)] attribute with a Display impl
webpack/mod.rs: Make WebpackChunkAssetReference::chunk_id() non-pub since it's only used internally

- Remove is_pure_constant: unescape {{/}} at compile time so rcstr! works for all constant format strings - require_context: use Display impl instead of awkward inline if in value_to_string attribute - webpack: make chunk_id() non-pub

nextjs-bot · 2026-02-13T03:31:29Z

Tests Passed

codspeed-hq · 2026-02-13T03:39:33Z

Merging this PR will not alter performance

✅ 17 untouched benchmarks
⏩ 3 skipped benchmarks¹

_{Comparing mmastrac/derive-value-to-string-followup (ab4fd35) with canary (8b2b0a6)}

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. ↩

nextjs-bot · 2026-02-13T03:56:12Z

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)	507ms	506ms	✓	▁▁▁▁▁
Cold (Ready in log)	500ms	502ms	✓	▇▁▆▇█
Cold (First Request)	1.025s	1.024s	✓	█▁███
Warm (Listen)	508ms	507ms	✓	▃▆▆▃▃
Warm (Ready in log)	504ms	500ms	✓	▂▁▂▂▁
Warm (First Request)	408ms	406ms	✓	▂▁▁▁▁

📦 Dev Server (Webpack) (Legacy)

📦 Dev Server (Webpack)

Metric	Canary	PR	Change	Trend
Cold (Listen)	455ms	455ms	✓	▁▁▁▁▁
Cold (Ready in log)	436ms	437ms	✓	▄▁▃▃▃
Cold (First Request)	1.733s	1.753s	✓	▃▁▂▃▃
Warm (Listen)	456ms	456ms	✓	▁▁▁▁▁
Warm (Ready in log)	436ms	437ms	✓	▄▁▃▃▄
Warm (First Request)	1.749s	1.771s	✓	▂▁▂▂▃

⚡ Production Builds

Metric	Canary	PR	Change	Trend
Fresh Build	4.628s	4.664s	✓	▁▃▁▁▁
Cached Build	4.723s	4.695s	✓	▁▃▁▁▂

📦 Production Builds (Webpack) (Legacy)

📦 Production Builds (Webpack)

Metric	Canary	PR	Change	Trend
Fresh Build	13.775s	13.800s	✓	▁▁▁▃▂
Cached Build	13.866s	13.882s	✓	▁▁▁▃▂
node_modules Size	472 MB	472 MB	✓	▁▁▁▁▁

📦 Bundle Sizes

Bundle Sizes

⚡ Turbopack

Client

Main Bundles: **437 kB** → **437 kB** ⚠️ +7 B

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

Server

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	758 B	762 B	✓
Total	758 B	762 B	⚠️ +4 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	450 B	448 B	✓
Total	450 B	448 B	✅ -2 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	62.6 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	62.6 kB	-
9544-HASH.js gzip	N/A	57.7 kB	-
Total	231 kB	231 kB	⚠️ +638 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	⚠️ +400 B

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	615 B	616 B	✓
middleware-r..fest.js gzip	156 B	155 B	✓
middleware.js gzip	32.9 kB	33.2 kB	✓
edge-runtime..pack.js gzip	842 B	842 B	✓
Total	34.5 kB	34.8 kB	⚠️ +272 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	🔴 +9.35 kB (+0%)
index.pack gzip	102 kB	103 kB	✓
index.pack.old gzip	102 kB	103 kB	🔴 +1.13 kB (+1%)
Total	4.05 MB	4.06 MB	⚠️ +10.9 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	✓

nextjs-bot added created-by: Turbopack team PRs by the Turbopack team. Turbopack Related to Turbopack with Next.js. labels Feb 13, 2026

mmastrac changed the title ~~[turbopack] Address review feedback for #[derive(ValueToString)]~~ [turbopack] Followup for #[derive(ValueToString)] Feb 13, 2026

lukesandberg approved these changes Feb 13, 2026

View reviewed changes

Merge branch 'canary' into mmastrac/derive-value-to-string-followup

ab4fd35

mmastrac marked this pull request as ready for review February 13, 2026 03:38

mmastrac merged commit 3badef4 into canary Feb 17, 2026
289 of 291 checks passed

mmastrac deleted the mmastrac/derive-value-to-string-followup branch February 17, 2026 16:58

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[turbopack] Followup for `#[derive(ValueToString)]`#89936

[turbopack] Followup for `#[derive(ValueToString)]`#89936
mmastrac merged 2 commits intocanaryfrom
mmastrac/derive-value-to-string-followup

mmastrac commented Feb 13, 2026 •

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Stats from current PR

✅ No significant changes detected

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mmastrac commented Feb 13, 2026 •

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