perf(kit): cache layer roots and short-circuit isIgnored relative

[danielroe]

🔗 Linked issue

📚 Description

spotted this while investigating #27106.

this avoids rebuilding layer paths and re-invoking pathe.relative (which resolves + splits + copies).

isIgnored is called so many times, so this really adds up.

[bolt-new-by-stackblitz]

Run & review this pull request in StackBlitz Codeflow.

[pkg-pr-new]

Open in StackBlitz

@nuxt/kit

npm i https://pkg.pr.new/@nuxt/kit@35015

@nuxt/nitro-server

npm i https://pkg.pr.new/@nuxt/nitro-server@35015

nuxt

npm i https://pkg.pr.new/nuxt@35015

@nuxt/rspack-builder

npm i https://pkg.pr.new/@nuxt/rspack-builder@35015

@nuxt/schema

npm i https://pkg.pr.new/@nuxt/schema@35015

@nuxt/vite-builder

npm i https://pkg.pr.new/@nuxt/vite-builder@35015

@nuxt/webpack-builder

npm i https://pkg.pr.new/@nuxt/webpack-builder@35015

commit: 6f25131

[codspeed-hq]

Merging this PR will improve performance by 10.07%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
✅ 19 untouched benchmarks
⏩ 3 skipped benchmarks¹

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
⚡	initial dev server build in the basic test fixture	906.6 ms	823.7 ms	+10.07%

---

_{Comparing perf/layer-path-cache (6f25131) with main (d4eaa42)}

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. ↩