perf(dev/lazy): fetch a lazy route in one request

[h-a-n-a]

A lazy import() in dev now costs one network request instead of two.

Before, the dev build turned a lazy boundary into its own chunk. The browser first fetched that proxy chunk, whose body then fetched the real module through /@vite/lazy. After that, a second promise chain ('rolldown:exports') handed the exports back to the importer.

before:  import('./route')
           -> GET /assets/route-proxy.js        (proxy chunk)
           -> GET /@vite/lazy?id=...            (real module)
           -> loadExports(proxyId)['rolldown:exports']

after:   import('./route')
           -> __rolldown_runtime__.requestLazy('route.js', () => import('/@vite/lazy?id=...'))
           -> GET /@vite/lazy?id=...            (real module, the only request)
           -> initModule('route.js')

Now the finalizer rewrites a lazy import() into a single runtime call. The proxy module still exists as a graph node, but its body is empty and is never executed, so no chunk is emitted for it.

[h-a-n-a]

• perf(dev/lazy): fetch a lazy route in one request #10789 👈 (View in Graphite)
• fix(test-dev-server): link the workspace rolldown before building vite #10857
• main

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[codspeed]

Merging this PR will not alter performance

✅ 7 untouched benchmarks
⏩ 10 skipped benchmarks¹

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_{Comparing 08-27-perf_dev_fetch_a_lazy_route_in_one_request (db96167) with main (a1ac2f8)²}

Footnotes

1. 10 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. ↩

2. No successful run was found on main (096569f) during the generation of this report, so a1ac2f8 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[chatgpt-codex-connector]

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[h-a-n-a]

Merge activity

• Sep 14, 8:49 AM UTC: The merge label 'graphite: merge-when-ready' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Sep 14, 8:49 AM UTC: h-a-n-a added this pull request to the Graphite merge queue.
• Sep 14, 8:56 AM UTC: Merged by the Graphite merge queue.