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Fix layout segment optimization: move app-page imports to server-utility transition#91701

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mischnic merged 1 commit into
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sokra/fix-layout-segment-optimization
Mar 20, 2026
Merged

Fix layout segment optimization: move app-page imports to server-utility transition#91701
mischnic merged 1 commit into
canaryfrom
sokra/fix-layout-segment-optimization

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@sokra

@sokra sokra commented Mar 20, 2026

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Summary

  • Add 'turbopack-transition': 'next-server-utility' to all server-side imports in the app-page.ts template so they are properly placed in the server utility layer, rather than relying on SharedMerged chunk groups to handle them
  • Remove the now-unnecessary next-server-utility transition from fillMetadataSegment import in app_page_loader_tree.rs
  • Add SharedMultiple chunk group variant to support multiple shared entries without a merge tag
    • This avoid passing the parent into SharedMerged, which did break the layout segment optimization.
  • Refactor app_module_graphs to combine client_shared_entries + has_layout_segments into a single Option parameter, simplifying the API and removing the dead code path for non-page endpoints

Test plan

  • Verify dev and production builds work with app pages that have layout segments
  • Verify route handlers still build correctly (no client runtime entries passed)
  • Run existing app-dir e2e tests

…aredMultiple chunk group

- Add 'turbopack-transition': 'next-server-utility' to all server-side imports in
  app-page.ts template so they are properly placed in the server utility layer
- Remove next-server-utility transition from fillMetadataSegment import in
  app_page_loader_tree.rs (no longer needed)
- Add SharedMultiple chunk group variant to support multiple shared entries
  without requiring a merge tag
- Refactor app_module_graphs to combine client_shared_entries parameter with
  has_layout_segments into a single Option parameter
- Simplify the module graph construction for the shared segment
@nextjs-bot nextjs-bot added created-by: Turbopack team PRs by the Turbopack team. Turbopack Related to Turbopack with Next.js. type: next labels Mar 20, 2026
@sokra sokra requested a review from mischnic March 20, 2026 09:58
@sokra sokra marked this pull request as ready for review March 20, 2026 10:01
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Stats from current PR

✅ No significant changes detected

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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:

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  • Cached = With existing .next directory

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  • Size: Changes < 1KB AND < 1% are insignificant
  • All other changes are flagged to catch regressions

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Metric Canary PR Change Trend
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📦 Dev Server (Webpack)

Metric Canary PR Change Trend
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Cold (First Request) 2.145s 2.157s ▂▂█▆▁
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Warm (Ready in log) 470ms 471ms ▁▁█▆▁
Warm (First Request) 2.148s 2.151s ▂▁█▆▁

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Metric Canary PR Change Trend
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Cached Build 3.830s 3.846s ▁▃▁▂▂
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📦 Production Builds (Webpack)

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📎 Tarball URL
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@codspeed-hq

codspeed-hq Bot commented Mar 20, 2026

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Merging this PR will degrade performance by 3.35%

❌ 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 packages-bundle.js[full] 965 ms 998.5 ms -3.35%

Comparing sokra/fix-layout-segment-optimization (655dbdb) with canary (883d93c)

Open in CodSpeed

Footnotes

  1. 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.

@mischnic mischnic merged commit 6a8a31a into canary Mar 20, 2026
284 of 293 checks passed
@mischnic mischnic deleted the sokra/fix-layout-segment-optimization branch March 20, 2026 12:00
ijjk pushed a commit that referenced this pull request Mar 20, 2026
…ity transition (#91701)

## Summary

- Add `'turbopack-transition': 'next-server-utility'` to all server-side imports in the `app-page.ts` template so they are properly placed in the server utility layer, rather than relying on `SharedMerged` chunk groups to handle them
- Remove the now-unnecessary `next-server-utility` transition from `fillMetadataSegment` import in `app_page_loader_tree.rs`
- Add `SharedMultiple` chunk group variant to support multiple shared entries without a merge tag
  - This avoid passing the `parent` into `SharedMerged`, which did break the layout segment optimization.
- Refactor `app_module_graphs` to combine `client_shared_entries` + `has_layout_segments` into a single `Option` parameter, simplifying the API and removing the dead code path for non-page endpoints

## Test plan

- [ ] Verify dev and production builds work with app pages that have layout segments
- [ ] Verify route handlers still build correctly (no client runtime entries passed)
- [ ] Run existing app-dir e2e tests
@github-actions github-actions Bot added the locked label Apr 3, 2026
@github-actions github-actions Bot locked as resolved and limited conversation to collaborators Apr 3, 2026
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