fix(vite): skip full reload for server only modules scanned by client css

[hi-ogawa]

Summary

• Closes Tailwind vite plugin forces full reload for server only modules managed by SSR frameworks #19744
• Closes HMR not working with tailwind 4.2.0 vitejs/vite-plugin-react#1118
• Closes HMR doesn't work in client components wakujs/waku#1963

The change in #19670 didn't take account for server only modules managed by SSR framework. Forcing full reload for this path breaks server HMR. This PR added a check to determine whether the same modified file has associated modules in a different environment module graph to avoid this.

Test plan

Added an integration test for React router HDR (server loader hmr). This test fails on main.

Also the local build is tested on @vitejs/plugin-rsc CI and confirmed the fix vitejs/vite-plugin-react#1132

[coderabbitai]

Walkthrough

This pull request enhances Hot Data Reload (HDR) handling in Vite integrations. A new test is added to integrations/vite/react-router.test.ts to verify that editing server-only loader dependencies triggers HDR instead of a full page reload. The test creates a React Router application with a server-only module that feeds data to a loader and confirms the update mechanism works correctly. Concurrently, the Tailwind CSS Vite plugin's hotUpdate function is modified to add cross-environment checks, ensuring updates are skipped when modules exist in other environments that are not assets, refining which file changes trigger reloads.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The PR title clearly describes the main change: preventing full reloads for server-only modules scanned by client CSS, which aligns with the core fix implemented in the changeset.
Description check	✅ Passed	The description is directly related to the changeset, explaining the regression fix, linked issues, test plan, and validation approach for preventing forced reloads of server-only modules.
Linked Issues check	✅ Passed	The PR addresses all three linked issues by implementing an environment-module-graph check that prevents full reloads for server-only modules, restoring HMR/HDR functionality across SSR and client boundaries.
Out of Scope Changes check	✅ Passed	All changes are directly related to the linked issue objectives: the Vite plugin fix targets server-only module handling, and the test case specifically validates server HMR behavior for React router HDR scenarios.

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[coderabbitai]

🧹 Nitpick comments (1)

packages/@tailwindcss-vite/src/index.ts (1)

222-229: Variable modules shadows the function parameter.

On line 225, const modules shadows the modules parameter from line 190. This reduces readability and could lead to bugs during future maintenance. Consider renaming to clarify it refers to modules in a different environment.

♻️ Suggested rename to avoid shadowing

          for (const environment of Object.values(server.environments)) {
            if (environment.name === this.environment.name) continue

-           const modules = environment.moduleGraph.getModulesByFile(file)
-           if (modules && [...modules].some((m) => m.type !== 'asset')) {
+           const envModules = environment.moduleGraph.getModulesByFile(file)
+           if (envModules && [...envModules].some((m) => m.type !== 'asset')) {
              return
            }
          }

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@packages/`@tailwindcss-vite/src/index.ts around lines 222 - 229, The local
const named "modules" inside the loop over server.environments shadows the
function parameter "modules"; rename the loop-local variable (e.g., to
"envModules" or "otherEnvModules") and update its usage in the condition that
calls environment.moduleGraph.getModulesByFile(file) and the subsequent
[...modules].some(...) check so that the parameter "modules" is not shadowed and
readability is restored.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@packages/`@tailwindcss-vite/src/index.ts:
- Around line 222-229: The local const named "modules" inside the loop over
server.environments shadows the function parameter "modules"; rename the
loop-local variable (e.g., to "envModules" or "otherEnvModules") and update its
usage in the condition that calls environment.moduleGraph.getModulesByFile(file)
and the subsequent [...modules].some(...) check so that the parameter "modules"
is not shadowed and readability is restored.

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ℹ️ Review info

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between bf2e2fe and 93ca94c.

📒 Files selected for processing (2)

• integrations/vite/react-router.test.ts
• packages/@tailwindcss-vite/src/index.ts