Ignore Vite build output when scanning sources

[OllieinCanada]

Summary

• Exclude Vite's resolved build output directory from Tailwind's native content scanner during builds.
• Prevent existing generated assets from becoming watch dependencies and triggering an infinite vite build --watch loop.
• Preserve explicitly configured @source files beneath the output directory.
• Preserve normal watch behavior for real source changes.
• Add a packed-consumer regression using exact vite@6.2.3, a custom assets output directory, emptyOutDir: false, and artifacts from a previous build.

Fixes #17412.

Test plan

pnpm --filter @tailwindcss/vite build
pnpm exec prettier --check packages/@tailwindcss-vite/src/index.ts integrations/vite/build-watch.test.ts
pnpm exec vitest run --root=./integrations vite/build-watch.test.ts
pnpm exec vitest run --root=./integrations vite/index.test.ts -t "watch mode"

The packed-artifact regression was also checked against an unmodified current-main tarball. The baseline enters a second build immediately after the first; the candidate remains idle, honors an explicit source inside the output directory, then rebuilds normally after editing a real source file. Swapping back to the baseline makes the same test fail again.

[greptile-apps]

Confidence Score: 5/5

The PR appears safe to merge; the prior explicit-source regression is resolved without reintroducing the automatic build-output watch loop.

_{Reviews (2) · Last reviewed commit: "Preserve explicit sources in Vite output"}

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Advanced

Run ID: 38d2b837-bbd9-49b8-8895-4bd7bdca51fe

📥 Commits

Reviewing files that changed from the base of the PR and between 3bfba3b and c9a445e.

📒 Files selected for processing (2)

• integrations/vite/build-watch.test.ts
• packages/@tailwindcss-vite/src/index.ts

Included review availability: Your plan provides up to 10 included reviews per hour; 8 remain after this review.

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Walkthrough

The Vite plugin passes the resolved build output directory to Root. Automatic source detection excludes files under that directory. Explicit @source paths use a separate scanner and remain available for candidate and watch dependency processing. A new integration test verifies that vite build --watch stays idle after the initial build and rebuilds after a source file changes.

Priority: ➖ Normal

Severity of issue fixed: Medium

Merge Risk: ⚪ Minimal · up to c9a44

The change excludes generated output from automatic scanning while retaining explicit source scanning and watch rebuilds.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Issue #17412 requires vite build --watch to avoid rebuilds caused by generated output and to rebuild after source changes. The Vite plugin resolves config.build.outDir during builds and adds a neg…
Out of Scope Changes check	✅ Passed	The changes stay within Issue #17412. The source changes exclude Vite-generated output from automatic Tailwind scanning and preserve explicitly requested sources. The added test covers the reported Vi…
Title check	✅ Passed	The title clearly summarizes the primary change: excluding Vite build output from source scanning.
Description check	✅ Passed	The description directly explains the source-scanning change, watch-loop prevention, explicit @source behavior, regression test, and linked issue.

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