perf(cli): reduce repeated config resolution and startup imports

[fengmk2]

From a workspace package, vp check --fix evaluates the Vite config seven times. Reuse its resolved config when selecting the config for each tool phase. This reduces evaluations to four and limits reuse to one command invocation.

Load Vite and Vitest only when config resolution is necessary. Return empty metadata when the workspace has no Vite config. Existing config files still use the full Vite resolver, including config functions and plugin hooks.

Reduce the benchmark limit to one config evaluation per process.

Single-run comparison with time

Before: a07ad93b9. After: 76ce17ced. Each case ran once per version, without warmup. Both versions used debug native bindings on Apple M4 Max, macOS 26.2, and Node v22.23.2.

The fixture contains three unformatted TypeScript files in packages/app/src. Config cases use export default { lint: {}, fmt: {} };. Each invocation starts with identical input files and an empty NODE_COMPILE_CACHE directory.

The before and after columns show real / user / sys from /usr/bin/time -p, in seconds.

Case and CLI arguments	Before (s)	After (s)	Real-time change
Root, no config: check --fix	0.72 / 0.37 / 0.12	0.54 / 0.30 / 0.09	-25.0%
Root, with config: check --fix	0.73 / 0.57 / 0.15	0.70 / 0.55 / 0.14	-4.1%
Root, with config: fmt	0.38 / 0.31 / 0.07	0.30 / 0.23 / 0.05	-21.1%
Root, with config: lint --fix	0.33 / 0.30 / 0.07	0.25 / 0.24 / 0.05	-24.2%
Package, with config: check --fix	0.74 / 0.59 / 0.16	0.71 / 0.57 / 0.15	-4.1%

Example invocation from the fixture root:

NODE_COMPILE_CACHE="$(mktemp -d)" /usr/bin/time -p \
  node "$CHECKOUT/packages/cli/bin/vp" fmt packages/app/src/*.ts

Set $CHECKOUT to the before or after worktree. Point the fixture's node_modules/vite-plus link to that worktree's packages/cli. Reset the input files before each invocation. Package cases run from packages/app with src/*.ts as the file arguments.

Stacked on #2779. Related to #2698.

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[github-actions]

CLI artifact sizes (76ce17c)

Final release artifacts built by the canonical build-upstream and build-windows-cli actions.
The dist rows use the Linux build. The core total excludes .node files to match the release artifact.

Artifact	Format	Base	PR	Change
packages/cli/dist	Directory total	2.12 MiB	2.12 MiB	+125 B (+0.01%)
packages/core/dist	Directory total	3.95 MiB	3.95 MiB	0 B (0.00%)
Combined package dist	Directory total	6.07 MiB	6.07 MiB	+125 B (+0.00%)
vp (Linux x64)	Binary	11.28 MiB	11.28 MiB	0 B (0.00%)
vp (Linux x64)	gzip -9	4.88 MiB	4.88 MiB	0 B (0.00%)
NAPI (Linux x64)	Binary	32.11 MiB	32.11 MiB	0 B (0.00%)
NAPI (Linux x64)	gzip -9	12.74 MiB	12.74 MiB	+691 B (+0.01%)
vp (macOS ARM64)	Binary	8.41 MiB	8.41 MiB	0 B (0.00%)
vp (macOS ARM64)	gzip -9	4.26 MiB	4.26 MiB	0 B (0.00%)
NAPI (macOS ARM64)	Binary	39.72 MiB	39.72 MiB	0 B (0.00%)
NAPI (macOS ARM64)	gzip -9	17.04 MiB	17.04 MiB	+158 B (+0.00%)
vp (Windows x64)	Binary	9.16 MiB	9.16 MiB	0 B (0.00%)
vp (Windows x64)	gzip -9	4.00 MiB	4.00 MiB	+2 B (+0.00%)
NAPI (Windows x64)	Binary	27.07 MiB	27.07 MiB	+1.00 KiB (+0.00%)
NAPI (Windows x64)	gzip -9	10.84 MiB	10.84 MiB	+210 B (+0.00%)
Trampoline (Windows x64)	Binary	13.50 KiB	13.50 KiB	0 B (0.00%)
Trampoline (Windows x64)	gzip -9	7.09 KiB	7.09 KiB	0 B (0.00%)
Installer (Windows x64)	Binary	4.56 MiB	4.56 MiB	0 B (0.00%)
Installer (Windows x64)	gzip -9	2.13 MiB	2.13 MiB	0 B (0.00%)

[github-actions]

Benchmark run for PR head 76ce17ced5f46d54ac16ad0627e714d0a8270bf5.

4 case(s) changed by more than ±5% in median time. Negative changes are faster; positive changes are slower.

Config performance

Baseline revision: 5bab3cf10565cfd983993348f67e05a1d5abf282.

Current revision: daef3076e332d6f0074b2484be29cecc612d9b34. Node v22.18.0; linux/x64; AMD EPYC.

Case	Median (ms), baseline → current	p95 (ms), baseline → current	Median change	Config evaluations (current, separate probe)
root/check/no-config	280.5 → 223.0	304.6 → 244.0	-57.6 ms (-20.5%)	0
root/check/minimal	484.4 → 472.5	491.4 → 557.1	-11.9 ms (-2.4%)	check: 1, oxfmt: 1, oxlint: 1, oxfmt: 1
root/check/defineConfig	491.5 → 479.5	505.0 → 730.7	-12.0 ms (-2.4%)	check: 1, oxfmt: 1, oxlint: 1, oxfmt: 1
package/check/minimal	503.4 → 472.7	510.6 → 507.1	-30.7 ms (-6.1%)	check: 1, oxfmt: 1, oxlint: 1, oxfmt: 1
package/check/blocks	497.0 → 476.3	506.9 → 537.0	-20.6 ms (-4.2%)	check: 1, oxfmt: 1, oxlint: 1, oxfmt: 1
root/fmt/minimal	222.2 → 167.3	226.9 → 195.8	-54.9 ms (-24.7%)	oxfmt: 1
root/lint/minimal	189.2 → 138.3	206.2 → 158.4	-50.9 ms (-26.9%)	oxlint: 1
root/staged/minimal	625.8 → 609.8	652.8 → 680.2	-15.9 ms (-2.5%)	staged: 1, check: 1, oxfmt: 1, oxlint: 1, oxfmt: 1
root/staged/noop	151.1 → 146.3	164.7 → 170.0	-4.8 ms (-3.2%)	staged: 1

Fresh processes, warm filesystem and Node compile caches. Config logging is disabled during timing.
A timing regression requires >20% and >40 ms median growth, with current p25 above baseline p75.

[liangmiQwQ]

@fengmk2 Thanks for your working on that. Just wanna notice: according to my profile and a contributor's analyze, the main cost of a vp check run is actually vite-plus package's import for every single Oxlint & Oxfmt child process (70%~80%, about 200ms in reality), analyzing and loading Vite+ config itself only takes about 20% for now. Improving config resolver is good but cannot completely solve the biggest performance cost.

I suggest a possible solution: instead of calling Oxlint / Oxfmt as child process, we can load them in the same Node.js process (using ESM import), the JS runtime should reuse the first import automatically.

Alternatively, we can change Oxlint / Oxfmt's behavior, to stop forcing import vite-plus package, and let Vite's config loader remove defineConfig macro import. This approach is a bit more complicated.

This is just some personal ideas, haven't been tested or verified. However, if our goal is to just improve that as soon as possible, we can treat these stacks as a incremental improvements.

Profiling: https://github.com/liang-demos/vite-plus-config-import-bench#readme

[fengmk2]

@liangmiQwQ I was only trying to conduct some experiments; the data results were not ideal, so I have stopped.