From d9c5e952ccb2645e8fac568f11dcc35b8851a019 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Fri, 1 Aug 2025 10:23:56 +0900
Subject: [PATCH 1/3] fix(rsc): avoid unnecessary server hmr due to tailwind
 module deps

---
 .../examples/basic/src/routes/tailwind/unused.tsx     |  1 +
 packages/plugin-rsc/src/plugin.ts                     | 11 +++++++++++
 2 files changed, 12 insertions(+)
 create mode 100644 packages/plugin-rsc/examples/basic/src/routes/tailwind/unused.tsx

diff --git a/packages/plugin-rsc/examples/basic/src/routes/tailwind/unused.tsx b/packages/plugin-rsc/examples/basic/src/routes/tailwind/unused.tsx
new file mode 100644
index 000000000..9599c3bb3
--- /dev/null
+++ b/packages/plugin-rsc/examples/basic/src/routes/tailwind/unused.tsx
@@ -0,0 +1 @@
+console.log('unused file text-[#f12345]')
diff --git a/packages/plugin-rsc/src/plugin.ts b/packages/plugin-rsc/src/plugin.ts
index a8b946ea2..fa0e7e552 100644
--- a/packages/plugin-rsc/src/plugin.ts
+++ b/packages/plugin-rsc/src/plugin.ts
@@ -398,6 +398,16 @@ export default function vitePluginRsc(
 
         if (!isInsideClientBoundary(ctx.modules)) {
           if (this.environment.name === 'rsc') {
+            // detect if this module is only created as css deps (e.g. tailwind)
+            // (NOTE: this is not necessary since Vite 7.1.0-beta.0 https://github.com/vitejs/vite/pull/20391 )
+            if (
+              ctx.modules
+                .flatMap((m) => [...m.importers])
+                .every((m) => m.id && isCSSRequest(m.id))
+            ) {
+              return
+            }
+
             // transform js to surface syntax errors
             for (const mod of ctx.modules) {
               if (mod.type === 'js') {
@@ -426,6 +436,7 @@ export default function vitePluginRsc(
             // Server files can be included in client module graph, for example,
             // when `addWatchFile` is used to track js files as style dependency (e.g. tailwind)
             // In this case, reload all importers (for css hmr), and return empty modules to avoid full-reload.
+            // (NOTE: this is not necessary since Vite 7.1.0-beta.0 https://github.com/vitejs/vite/pull/20391 )
             const env = ctx.server.environments.rsc!
             const mod = env.moduleGraph.getModuleById(ctx.file)
             if (mod) {

From 98e3c9c1fefca9c2760fa3c15b8ff3cec2c089e7 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Fri, 1 Aug 2025 10:34:20 +0900
Subject: [PATCH 2/3] fix: tweak condition

---
 packages/plugin-rsc/examples/basic/src/styles.css |  2 +-
 packages/plugin-rsc/src/plugin.ts                 | 14 ++++++++------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/packages/plugin-rsc/examples/basic/src/styles.css b/packages/plugin-rsc/examples/basic/src/styles.css
index e34d4399d..2cb11909b 100644
--- a/packages/plugin-rsc/examples/basic/src/styles.css
+++ b/packages/plugin-rsc/examples/basic/src/styles.css
@@ -1,4 +1,4 @@
-@import 'tailwindcss' source('./');
+@import 'tailwindcss';
 
 button {
   @apply bg-gray-100 mx-1 px-2 border hover:bg-gray-200 active:bg-gray-300;
diff --git a/packages/plugin-rsc/src/plugin.ts b/packages/plugin-rsc/src/plugin.ts
index fa0e7e552..e895c8531 100644
--- a/packages/plugin-rsc/src/plugin.ts
+++ b/packages/plugin-rsc/src/plugin.ts
@@ -400,12 +400,14 @@ export default function vitePluginRsc(
           if (this.environment.name === 'rsc') {
             // detect if this module is only created as css deps (e.g. tailwind)
             // (NOTE: this is not necessary since Vite 7.1.0-beta.0 https://github.com/vitejs/vite/pull/20391 )
-            if (
-              ctx.modules
-                .flatMap((m) => [...m.importers])
-                .every((m) => m.id && isCSSRequest(m.id))
-            ) {
-              return
+            if (ctx.modules.length === 1) {
+              const importers = [...ctx.modules[0]!.importers]
+              if (
+                importers.length > 0 &&
+                importers.every((m) => m.id && isCSSRequest(m.id))
+              ) {
+                return
+              }
             }
 
             // transform js to surface syntax errors

From 8a9e3f8ea0c8a88a3a3e1b5017215341c69f89f6 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Fri, 1 Aug 2025 11:05:55 +0900
Subject: [PATCH 3/3] test: add e2e

---
 packages/plugin-rsc/e2e/basic.test.ts          | 18 ++++++++++++++++++
 packages/plugin-rsc/e2e/fixture.ts             |  3 +++
 .../basic/src/framework/entry.browser.tsx      |  3 ++-
 .../basic/src/routes/tailwind/unused.tsx       |  2 +-
 packages/plugin-rsc/src/plugin.ts              |  2 +-
 5 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/packages/plugin-rsc/e2e/basic.test.ts b/packages/plugin-rsc/e2e/basic.test.ts
index 6fff84076..a2c9e4c20 100644
--- a/packages/plugin-rsc/e2e/basic.test.ts
+++ b/packages/plugin-rsc/e2e/basic.test.ts
@@ -637,6 +637,24 @@ function defineTest(f: Fixture) {
         'rgb(255, 0, 0)',
       )
     })
+
+    test('tailwind no redundant server hmr', async ({ page }) => {
+      await page.goto(f.url())
+      await waitForHydration(page)
+      const logs: string[] = []
+      page.on('console', (msg) => {
+        if (msg.type() === 'log') {
+          logs.push(msg.text())
+        }
+      })
+      f.createEditor('src/routes/tailwind/unused.tsx').resave()
+      await page.waitForTimeout(200)
+      f.createEditor('src/routes/tailwind/server.tsx').resave()
+      await page.waitForTimeout(200)
+      expect(logs).toEqual([
+        expect.stringMatching(/\[vite-rsc:update\].*\/tailwind\/server.tsx/),
+      ])
+    })
   })
 
   test('temporary references @js', async ({ page }) => {
diff --git a/packages/plugin-rsc/e2e/fixture.ts b/packages/plugin-rsc/e2e/fixture.ts
index aa61f332a..1848ba3f5 100644
--- a/packages/plugin-rsc/e2e/fixture.ts
+++ b/packages/plugin-rsc/e2e/fixture.ts
@@ -142,6 +142,9 @@ export function useFixture(options: {
       reset(): void {
         fs.writeFileSync(filepath, originalFiles[filepath]!)
       },
+      resave(): void {
+        fs.writeFileSync(filepath, current)
+      },
     }
   }
 
diff --git a/packages/plugin-rsc/examples/basic/src/framework/entry.browser.tsx b/packages/plugin-rsc/examples/basic/src/framework/entry.browser.tsx
index 473fc492d..1998e86ff 100644
--- a/packages/plugin-rsc/examples/basic/src/framework/entry.browser.tsx
+++ b/packages/plugin-rsc/examples/basic/src/framework/entry.browser.tsx
@@ -70,7 +70,8 @@ async function main() {
 
   // implement server HMR by trigering re-fetch/render of RSC upon server code change
   if (import.meta.hot) {
-    import.meta.hot.on('rsc:update', () => {
+    import.meta.hot.on('rsc:update', (e) => {
+      console.log('[vite-rsc:update]', e.file)
       fetchRscPayload()
     })
   }
diff --git a/packages/plugin-rsc/examples/basic/src/routes/tailwind/unused.tsx b/packages/plugin-rsc/examples/basic/src/routes/tailwind/unused.tsx
index 9599c3bb3..98476b011 100644
--- a/packages/plugin-rsc/examples/basic/src/routes/tailwind/unused.tsx
+++ b/packages/plugin-rsc/examples/basic/src/routes/tailwind/unused.tsx
@@ -1 +1 @@
-console.log('unused file text-[#f12345]')
+console.log(<div className="unused">unused</div>)
diff --git a/packages/plugin-rsc/src/plugin.ts b/packages/plugin-rsc/src/plugin.ts
index e895c8531..3016a3b68 100644
--- a/packages/plugin-rsc/src/plugin.ts
+++ b/packages/plugin-rsc/src/plugin.ts
@@ -406,7 +406,7 @@ export default function vitePluginRsc(
                 importers.length > 0 &&
                 importers.every((m) => m.id && isCSSRequest(m.id))
               ) {
-                return
+                return []
               }
             }