Do not retain the finished build's plugin context in @tailwindcss/vite

[lazerg]

Summary

The build plugin's Root caches a compiler for as long as the plugin instance lives, but that compiler holds onto the PluginContext from the transform call that first created it, through the onDependency callback passed to compile(). Nothing ever released that captured context. In a plain vite build this never shows up because the process exits right after, but if the same plugin instance is reused afterward (Astro's static build runs the SSR/prerender build and then generates every page in the same process) the finished build's context, and the native Rolldown arena behind it, stay alive while the next phase starts allocating on top of it.

This clears the cached roots for an environment as soon as its bundle closes, so the reference is dropped before anything else gets a chance to run.

Fixes #20501

Test plan

Added a test that wraps the build plugin's transform handler to grab a WeakRef on the PluginContext from the first call, runs a Vite 8 (Rolldown) build, forces a few GCs, and checks the context was collected. It fails on the old code and passes with the fix (only reproduces under Rolldown, not Rollup). Ran the full integrations/vite suite locally and it passes.

[coderabbitai]

Understand this PR’s impact

Explore downstream dependencies and potential security impact with Blast Radius.

View blast radius →

Important

Review skipped

Review was skipped as selected files did not have any reviewable changes.

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Advanced

Run ID: 0d12ec33-86b4-44af-b0e2-ce255699b9e6

📥 Commits

Reviewing files that changed from the base of the PR and between d9541bd and ff8a6f6.

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

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: 23ba9d88-8ccc-4aee-ad5e-ddac616da700

📥 Commits

Reviewing files that changed from the base of the PR and between 44eca1b and d9541bd.

📒 Files selected for processing (2)

• integrations/vite/plugin-context-leak.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.

---

Walkthrough

The Vite build plugin now preserves cached roots during watch rebuilds. For non-watch builds, closeBundle clears cached roots so finished-build PluginContext instances can be collected. A Vite 8 integration test verifies this with WeakRef and forced garbage collection. The changelog records the fix for memory retention in long-lived build processes.

Priority: ⬆️ High

Severity of issue fixed: High

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly describes the main change: releasing the finished build's plugin context in @tailwindcss/vite.
Description check	✅ Passed	The description explains the retained PluginContext issue, the root-cache fix, watch-mode behavior, and the garbage-collection test.
Linked Issues check	✅ Passed	Issue #20501 requires release of cached build roots after a completed bundle, retention of roots during watch rebuilds, and a test for context collection. packages/@tailwindcss-vite/src/index.ts cle…
Out of Scope Changes check	✅ Passed	The source change, regression test, and CHANGELOG.md entry directly support Issue #20501. The changes add no unrelated product behavior or public API changes.

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[greptile-apps]

Confidence Score: 5/5

The PR appears safe to merge, with cleanup correctly limited to completed non-watch builds and regression coverage for the retained context.

_{Reviews (3) · Last reviewed commit: "Don't clear the build plugin's Root cach..."}