[akira28]

./dev.sh isolated-watch and docs-builder serve no longer rebuild the frontend endlessly. The Vite watcher now ignores its own _static output, so it builds once and then waits for real source changes.

Affects: Site UI, Isolated builds

Prompt summary: The move from Parcel to Vite in #4383 broke ./dev.sh isolated-watch. The goal is to make the isolated watch flow usable again.

Why

tailwind.config.js scans ./**/*.{js,…}, and that glob also matches the built _static/*.js files. The Tailwind Vite plugin watches every file it scans. Under vite build --watch, each build writes to _static, and those writes start the next build. The serve process runs npm run watch, so the frontend never settles.

What

Watch mode ignores build output

Vite's watcher excludes _static/** and node_modules/**. Writes to the build output no longer trigger a rebuild, and edits under Assets/ still do.

One-shot builds stay one-shot

Vite treats any non-null build.watch as a request to watch. The config sets the exclusion only when Vite runs with --watch. Without that guard, the npm run build step in MSBuild never exits and the .NET build hangs.

A test guards both modes

vite.config.test.ts loads the config with and without --watch. It fails if a one-shot build turns into a watcher, or if watch mode stops ignoring _static.

Verify

cd src/Elastic.Documentation.Site && npx jest vite.config.test.ts

./dev.sh isolated-stop && ./dev.sh isolated-watch
# expect a single "[npm run watch]: build started" line, then the site on http://localhost:3000

Editing a file under src/Elastic.Documentation.Site/Assets/ should trigger exactly one more build.

🤖 Generated with Claude Code

[infra-vault-gh-plugin-prod]

Severity: P3 (Low)

Add automated regression coverage for the build/watch lifecycle. This fix has no accompanying test that verifies a normal build exits, watch mode settles after writing _static, and a source edit triggers another build. Those are the behaviors this change must preserve, and without coverage the rebuild loop or a hanging frontend build can return unnoticed.

_{Generated by Libra. React with 👍 or 👎 to give feedback on this comment.}

[akira28]

Added vite.config.test.ts in c90ecf1. It covers both regressions at the config level: a one-shot vite build keeps build.watch unset (otherwise the MSBuild step hangs), and --watch excludes _static/** (otherwise every build triggers the next). I checked that it fails when watch is forced on. A real vite build --watch lifecycle test, which edits a file and counts rebuilds, would need several seconds of real Vite and Tailwind builds and would be flaky, so I left it out of the Jest suite.

[github-actions]

Docs preview (local build)

Handbook preview: https://docs-v3-preview.elastic.dev/elastic/docs-builder/pull/4407/