Use page extensions in next-swc transforms applying to pages by eps1lon · Pull Request #90650 · vercel/next.js

eps1lon · 2026-02-27T13:13:09Z

Previously some transforms hardcoded possible page extensions when matching pages (or layout.js, or default.js). This doesn't necessarily cover all pages as configured. Now we're using config.pageExtensions to consider modules consistently as pages.

This pull request contains changes generated by a Cursor Cloud Agent

Replace hardcoded page extension regex patterns (ts|js)x? with dynamic patterns built from configured page_extensions. This ensures custom pageExtensions from next.config.js are respected in: - react_server_components.rs: error file and app entry detection - debug_instant_stack.rs: page/layout/default file matching - next_strip_page_exports.rs: _document file exclusion The page_extensions are passed through: - Options struct in next-custom-transforms (with serde default for backward compatibility) - Turbopack wrappers read from NextConfig::page_extensions() - Webpack/SWC path via TransformOptions and swc/options.ts Co-authored-by: Sebastian "Sebbie" Silbermann <silbermann.sebastian@gmail.com>

Co-authored-by: Sebastian "Sebbie" Silbermann <silbermann.sebastian@gmail.com>

cursor · 2026-02-27T13:13:13Z

Cursor Agent can help with this pull request. Just @cursor in comments and I'll start working on changes in this branch.
_{Learn more about Cursor Agents}

…Options The pageExtensions parameter was added to the type annotations but was missing from the parameter destructuring, causing TypeScript errors: 'Cannot find name pageExtensions' and 'No value exists in scope for the shorthand property pageExtensions'. Co-authored-by: Sebastian "Sebbie" Silbermann <silbermann.sebastian@gmail.com>

Upstream changed the transform from Fold+fold_pass to VisitMut+visit_mut_pass. Resolved by keeping our page_extensions changes while adopting the new VisitMut pattern from canary. Co-authored-by: Sebastian "Sebbie" Silbermann <silbermann.sebastian@gmail.com>

nextjs-bot · 2026-02-27T13:40:48Z

Stats from current PR

🟢 1 improvement

Metric	Canary	PR	Change	Trend
node_modules Size	476 MB	475 MB	🟢 275 kB (0%)	▁▁▁▁▁

📊 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)	966ms	963ms	✓	▁▁▁▃▁
Cold (Ready in log)	935ms	929ms	✓	▂▂▂▃▁
Cold (First Request)	1.709s	1.695s	✓	▄▄▄▄▁
Warm (Listen)	964ms	963ms	✓	▁▁▁▃▁
Warm (Ready in log)	930ms	940ms	✓	▁▁▁▃▁
Warm (First Request)	746ms	723ms	✓	▁▁▁▃▁

📦 Dev Server (Webpack) (Legacy)

📦 Dev Server (Webpack)

Metric	Canary	PR	Change	Trend
Cold (Listen)	507ms	507ms	✓	▁▁▁▁▅
Cold (Ready in log)	473ms	476ms	✓	▁▄▃▁▅
Cold (First Request)	2.106s	2.091s	✓	▁▂▂▁▅
Warm (Listen)	508ms	508ms	✓	▁▁▁▁▅
Warm (Ready in log)	473ms	474ms	✓	▁▂▂▁▅
Warm (First Request)	2.085s	2.109s	✓	▁▁▁▁▅

⚡ Production Builds

Metric	Canary	PR	Change	Trend
Fresh Build	6.488s	6.593s	✓	▁▁▁▆▁
Cached Build	6.429s	6.617s	✓	▁▁▁▅▁

📦 Production Builds (Webpack) (Legacy)

📦 Production Builds (Webpack)

Metric	Canary	PR	Change	Trend
Fresh Build	15.583s	15.663s	✓	▂▁▁▁▄
Cached Build	15.660s	15.765s	✓	▁▁▁▁▄
node_modules Size	476 MB	475 MB	🟢 275 kB (0%)	▁▁▁▁▁

📦 Bundle Sizes

Bundle Sizes

⚡ Turbopack

Client

Main Bundles: **401 kB** → **401 kB** ✅ -430 B

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

Server

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	769 B	764 B	✓
Total	769 B	764 B	✅ -5 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	453 B	451 B	✓
Total	453 B	451 B	✅ -2 B

📦 Webpack

Client

Main Bundles

	Canary	PR	Change
5528-HASH.js gzip	5.54 kB	N/A	-
6280-HASH.js gzip	58.8 kB	N/A	-
6335.HASH.js gzip	169 B	N/A	-
912-HASH.js gzip	4.59 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	253 B	🟢 3 B (-1%)
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	4.59 kB	-
2889.HASH.js gzip	N/A	169 B	-
5602-HASH.js gzip	N/A	5.55 kB	-
6948ada0-HASH.js gzip	N/A	62.6 kB	-
9544-HASH.js gzip	N/A	59.1 kB	-
Total	233 kB	233 kB	⚠️ +314 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	579 B	581 B	✓
index-HASH.js gzip	260 B	260 B	✓
link-HASH.js gzip	2.51 kB	2.5 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	7.98 kB	7.97 kB	✅ -13 B

Server

Edge SSR

	Canary	PR	Change
edge-ssr.js gzip	125 kB	125 kB	✓
page.js gzip	254 kB	255 kB	✓
Total	379 kB	379 kB	⚠️ +102 B

Middleware

	Canary	PR	Change
middleware-b..fest.js gzip	617 B	614 B	✓
middleware-r..fest.js gzip	156 B	155 B	✓
middleware.js gzip	43.6 kB	43.8 kB	✓
edge-runtime..pack.js gzip	842 B	842 B	✓
Total	45.3 kB	45.5 kB	⚠️ +203 B

Build Details

Build Manifests

	Canary	PR	Change
_buildManifest.js gzip	714 B	718 B	✓
Total	714 B	718 B	⚠️ +4 B

Build Cache

	Canary	PR	Change
0.pack gzip	4.06 MB	4.03 MB	🟢 27.2 kB (-1%)
index.pack gzip	104 kB	103 kB	🟢 1.27 kB (-1%)
index.pack.old gzip	103 kB	104 kB	🔴 +1.1 kB (+1%)
Total	4.27 MB	4.24 MB	✅ -27.3 kB

🔄 Shared (bundler-independent)

Runtimes

	Canary	PR	Change
app-page-exp...dev.js gzip	321 kB	320 kB	✓
app-page-exp..prod.js gzip	170 kB	170 kB	✓
app-page-tur...dev.js gzip	320 kB	320 kB	✓
app-page-tur..prod.js gzip	170 kB	170 kB	✓
app-page-tur...dev.js gzip	317 kB	316 kB	✓
app-page-tur..prod.js gzip	168 kB	168 kB	✓
app-page.run...dev.js gzip	317 kB	317 kB	✓
app-page.run..prod.js gzip	168 kB	168 kB	✓
app-route-ex...dev.js gzip	70.8 kB	70.8 kB	✓
app-route-ex..prod.js gzip	49.3 kB	49.2 kB	✓
app-route-tu...dev.js gzip	70.9 kB	70.9 kB	✓
app-route-tu..prod.js gzip	49.3 kB	49.3 kB	✓
app-route-tu...dev.js gzip	70.5 kB	70.4 kB	✓
app-route-tu..prod.js gzip	49 kB	49 kB	✓
app-route.ru...dev.js gzip	70.4 kB	70.4 kB	✓
app-route.ru..prod.js gzip	49 kB	49 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	32.9 kB	32.9 kB	✓
pages-turbo....dev.js gzip	52.6 kB	52.6 kB	✓
pages-turbo...prod.js gzip	38.5 kB	38.5 kB	✓
pages.runtim...dev.js gzip	52.6 kB	52.6 kB	✓
pages.runtim..prod.js gzip	38.5 kB	38.5 kB	✓
server.runti..prod.js gzip	62 kB	61.9 kB	✓
Total	2.83 MB	2.82 MB	✅ -3.81 kB

📝 Changed Files (25 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
pages-api-tu..ntime.dev.js
pages-api-tu..time.prod.js
pages-api.runtime.dev.js
pages-api.ru..time.prod.js
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📎 Tarball URL

https://vercel-packages.vercel.app/next/commits/ccd1be6a7edde53c658150d795f383a1df63aabc/next

nextjs-bot · 2026-02-27T13:45:10Z

Tests Passed

codspeed-hq · 2026-02-27T13:48:55Z

Merging this PR will degrade performance by 3.09%

❌ 1 regressed benchmark
✅ 16 untouched benchmarks
⏩ 3 skipped benchmarks¹

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	`BASE`	`HEAD`	Efficiency
❌	Simulation	`react-dom-client.development.js[full]`	494.6 ms	510.4 ms	-3.09%

_{Comparing cursor/page-extensions-regex-usage-020f (ccd1be6) with canary (ad3296b)}

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. ↩

The #[serde(flatten)] on TransformOptions.swc causes unknown fields to be passed to swc_core::base::config::Options, which rejects them. Instead of a top-level page_extensions field, extract it from the server_components config where it's already available via Options. This fixes the 'unknown field pageExtensions' serde deserialization error in the webpack SWC transform path. Co-authored-by: Sebastian "Sebbie" Silbermann <silbermann.sebastian@gmail.com>

crates/next-core/src/next_shared/transforms/next_strip_page_exports.rs

…ports.rs Co-authored-by: Niklas Mischkulnig <4586894+mischnic@users.noreply.github.com>

crates/next-core/src/next_shared/transforms/next_strip_page_exports.rs

Co-authored-by: vercel[bot] <35613825+vercel[bot]@users.noreply.github.com>

crates/next-core/src/next_shared/transforms/next_strip_page_exports.rs

…ports.rs Co-authored-by: Niklas Mischkulnig <4586894+mischnic@users.noreply.github.com>

Co-authored-by: Cursor Agent <cursoragent@cursor.com> Co-authored-by: Niklas Mischkulnig <4586894+mischnic@users.noreply.github.com> Co-authored-by: vercel[bot] <35613825+vercel[bot]@users.noreply.github.com>

cursoragent and others added 2 commits February 27, 2026 13:09

Fix formatting (cargo fmt + prettier)

021873a

Co-authored-by: Sebastian "Sebbie" Silbermann <silbermann.sebastian@gmail.com>

nextjs-bot added created-by: Next.js team PRs by the Next.js team. Turbopack Related to Turbopack with Next.js. type: next labels Feb 27, 2026

eps1lon changed the title ~~Page extensions regex usage~~ Use page extensions in next-swc transforms applying to pages Feb 27, 2026

eps1lon added the CI approved Approve running CI for fork label Feb 27, 2026

eps1lon mentioned this pull request Feb 27, 2026

[instant] Don't add debug stack to random unstable_instant exports #90273

Merged

cursoragent and others added 2 commits February 27, 2026 13:56

Fix prettier formatting in options.ts

1a02f11

eps1lon marked this pull request as ready for review February 28, 2026 13:22

eps1lon requested a review from unstubbable February 28, 2026 13:44

unstubbable requested review from mischnic and removed request for unstubbable March 4, 2026 12:19

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…ports.rs Co-authored-by: Niklas Mischkulnig <4586894+mischnic@users.noreply.github.com>

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…ports.rs Co-authored-by: Niklas Mischkulnig <4586894+mischnic@users.noreply.github.com>

eps1lon enabled auto-merge (squash) March 4, 2026 13:12

eps1lon merged commit cb44b43 into canary Mar 4, 2026
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eps1lon deleted the cursor/page-extensions-regex-usage-020f branch March 4, 2026 16:13

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Use page extensions in next-swc transforms applying to pages#90650

Use page extensions in next-swc transforms applying to pages#90650
eps1lon merged 9 commits intocanaryfrom
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