Turbopack: move assignment_scopes computation into ImportMap by mischnic · Pull Request #92835 · vercel/next.js

mischnic · 2026-04-15T16:24:30Z

I'm moving all of the export-related logic into EvalContext (and thus ImportMap) so that VarGraph is only needed for computing the references, and not the exports.

The change in the snapshots is

-*anonymous function 170* (const after eval) = (...) => [file]
+*anonymous function 170* = (...) => [file]

which is fine, since computing the "is reassigned" data for something that isn't actually a variable was non-sensical anyway.

mischnic · 2026-04-15T16:24:47Z

Turbopack: compute exports without full analysis #92823
Turbopack: move assignment_scopes computation into ImportMap #92835 👈 (View in Graphite)
Turbopack: remove StarImportAnalyzer #92830
Turbopack: refactor export analysis #92781 : 1 other dependent PR (#92834 )
Turbopack: refactor ESM codegen generation #92777
Turbopack: remove webpack chunk detection #92773
canary

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nextjs-bot · 2026-04-15T16:41:10Z

Tests Passed

codspeed-hq · 2026-04-15T16:46:07Z

Merging this PR will improve performance by 3.73%

⚡ 2 improved benchmarks
✅ 15 untouched benchmarks
⏩ 3 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	`BASE`	`HEAD`	Efficiency
⚡	Simulation	`app-page-turbo.runtime.prod.js[full]`	640 ms	617 ms	+3.73%
⚡	Simulation	`packages-bundle.js[full]`	983.9 ms	949.4 ms	+3.64%

_{Comparing mischnic/move-assignment-scopes-into-importmap (644a490) with canary (69b9c4b)}

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 · 2026-04-15T17:00:30Z

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	455ms	✓	▁█▁▁▁
Cold (Ready in log)	440ms	440ms	✓	█▁█▇▃
Cold (First Request)	829ms	823ms	✓	▁█▁▁█
Warm (Listen)	456ms	455ms	✓	▁▅▅█▅
Warm (Ready in log)	439ms	438ms	✓	▅▅▄▂▄
Warm (First Request)	337ms	337ms	✓	█▄▇▂▄

📦 Dev Server (Webpack) (Legacy)

📦 Dev Server (Webpack)

Metric	Canary	PR	Change	Trend
Cold (Listen)	456ms	456ms	✓	████▁
Cold (Ready in log)	437ms	438ms	✓	▆█▅▂▃
Cold (First Request)	1.861s	1.876s	✓	▆█▅▆▆
Warm (Listen)	455ms	456ms	✓	█▁▅▅▅
Warm (Ready in log)	436ms	436ms	✓	▅▇▃▂▃
Warm (First Request)	1.881s	1.870s	✓	▆█▆▇█

⚡ Production Builds

Metric	Canary	PR	Change	Trend
Fresh Build	3.937s	3.911s	✓	▅▂▅█▃
Cached Build	3.976s	3.964s	✓	▅▂▅█▁

📦 Production Builds (Webpack) (Legacy)

📦 Production Builds (Webpack)

Metric	Canary	PR	Change	Trend
Fresh Build	14.375s	14.440s	✓	▄▇▂▂▁
Cached Build	14.508s	14.574s	✓	▁█▄▃▂
node_modules Size	493 MB	493 MB	✓	█████

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https://vercel-packages.vercel.app/next/commits/644a49029b8a891f330397da4b1c87bafc941cfa/next

mischnic mentioned this pull request Apr 15, 2026

Turbopack: remove StarImportAnalyzer #92830

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nextjs-bot added created-by: Turbopack team PRs by the Turbopack team. Turbopack Related to Turbopack with Next.js. labels Apr 15, 2026

mischnic changed the title ~~arrow functions~~ Turbopack: move assignment_scopes computation into ImportMap Apr 15, 2026

lukesandberg reviewed Apr 15, 2026

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Comment thread turbopack/crates/turbopack-ecmascript/src/analyzer/graph.rs Outdated

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Comment thread turbopack/crates/turbopack-ecmascript/src/analyzer/imports.rs Outdated

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Comment thread turbopack/crates/turbopack-ecmascript/src/analyzer/imports.rs

mischnic force-pushed the mischnic/remove-StarImportAnalyzer branch from 14aab78 to e489805 Compare April 15, 2026 18:43

mischnic force-pushed the mischnic/move-assignment-scopes-into-importmap branch 2 times, most recently from 2794eeb to cc60bcd Compare April 15, 2026 18:52

mischnic force-pushed the mischnic/remove-StarImportAnalyzer branch from e489805 to 487822d Compare April 15, 2026 18:52

mischnic changed the base branch from mischnic/remove-StarImportAnalyzer to graphite-base/92835 April 15, 2026 20:20

mischnic force-pushed the mischnic/move-assignment-scopes-into-importmap branch from cc60bcd to 5477e7a Compare April 15, 2026 20:20

mischnic force-pushed the graphite-base/92835 branch from 487822d to 45e5ad7 Compare April 15, 2026 20:20

graphite-app Bot changed the base branch from graphite-base/92835 to canary April 15, 2026 20:21

mischnic force-pushed the mischnic/move-assignment-scopes-into-importmap branch from 5477e7a to fed3b03 Compare April 15, 2026 20:21

mischnic added 5 commits April 15, 2026 22:28

arrow functions

093b554

move assignment_scopes into ImportMap

55eea9c

remove VarMeta

bf8197a

import type instead

8b8759b

getter and setter

644a490

mischnic force-pushed the mischnic/move-assignment-scopes-into-importmap branch from 944e614 to 644a490 Compare April 15, 2026 20:32

mischnic marked this pull request as ready for review April 15, 2026 20:34

mischnic requested a review from lukesandberg April 15, 2026 20:34

lukesandberg approved these changes Apr 15, 2026

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mischnic mentioned this pull request Apr 15, 2026

Turbopack: compute exports without full analysis #92823

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mischnic merged commit bf4de72 into canary Apr 15, 2026
188 of 189 checks passed

mischnic deleted the mischnic/move-assignment-scopes-into-importmap branch April 15, 2026 21:35

This was referenced Apr 23, 2026

fix(deps): vuln next (major → 16.2.4) [website] DataDog/vault#82

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fix(deps): vuln major upgrades — 4 packages (major: 1 · unstable: 1 · minor: 2) [src/frontend] DataDog/opentelemetry-demo#79

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Turbopack: move assignment_scopes computation into ImportMap#92835

Turbopack: move assignment_scopes computation into ImportMap#92835
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