Run Astro as a regular Vite plugin (astro/vite)

[matthewp]

Changes

• Adds astro() from astro/vite, so Astro runs as a regular Vite plugin: no Astro CLI, no astro.config.mjs. The Astro config, integrations included, is passed inline, and vite, vite build and vite preview do the work. Spike, draft only.
• Setup runs eagerly when astro() is called, because Vite collects plugins before its config hooks run: integration hooks run, then createVite, as in the CLI. The command is inferred from NODE_ENV, or passed explicitly with defineConfig((env) => ({ plugins: [astro(config, env)] })). A config hook throws if the guess doesn't match Vite's real command.
• Vite's builder re-evaluates vite.config once per build environment, so the build-mode setup is cached per project root and cleared in buildApp. Integration hooks run once, and every environment shares one set of plugin instances.
• Integration server and build hooks map to Vite hooks:
  • astro:server:start/done → httpServer listening/close
  • astro:build:done → buildApp post
• Content collections and .astro/ types work in dev and build. The dev content setup moves out of core/dev/dev.ts into content/dev-setup.ts, and the plugin reuses it.
• Session telemetry is recorded from configureServer, buildApp and configurePreviewServer, not when the config is evaluated. Session events get a new source: 'cli' | 'vite-plugin' field.
• Small core refactors so the plugins work outside the CLI:
  • Plugins can read command from Vite.
  • Route info, env mode and private env are resolved lazily.
  • static-build.ts exposes the build environment config.
• Works: .astro pages, React islands, live updates in dev, SSR with @astrojs/node, actions, astro:env, content collections, ClientRouter, and other Vite plugins alongside (Tailwind in the example).
• Known gaps:
  • vite preview for SSR output.
  • Integrations see vite preview as build.
  • Astro's server.* options.
  • Fonts server teardown after build.
  • CLI-only commands (add, check, sync).

Testing

• Adds examples/vite-plugin-react, which uses @astrojs/react, a content collection and Tailwind, run with vite / vite build / vite preview.
• Adds eventCliSession() unit tests for the source field.

Docs

• None yet. This is an experimental spike; docs follow if the direction is accepted.

[changeset-bot]

🦋 Changeset detected

Latest commit: 685dbd9

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
astro	Minor

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[github-actions]

This PR is blocked because it contains a minor changeset. A reviewer will merge this at the next release if approved.

[github-actions]

e18e dependency analysis

No dependency warnings found.

[codspeed]

Merging this PR will not alter performance

✅ 21 untouched benchmarks

---

_{Comparing spike/astro-vite-plugin (685dbd9) with main (2b8b2e8)¹}

Footnotes

1. No successful run was found on main (c17d920) during the generation of this report, so 2b8b2e8 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[pkg-pr-new]

npm i https://pkg.pr.new/astro@18121

commit: 685dbd9