fix(hmr): trigger page reload when calling invalidate on root module (#16636)

Author: ArnaudBarre

Diff for: packages/vite/src/node/server/hmr.ts

@@ -228,7 +228,8 @@ export function updateModules(
   const updates: Update[] = []
   const invalidatedModules = new Set<ModuleNode>()
   const traversedModules = new Set<ModuleNode>()
-  let needFullReload: HasDeadEnd = false
+  // Modules could be empty if a root module is invalidated via import.meta.hot.invalidate()
+  let needFullReload: HasDeadEnd = modules.length === 0
 
   for (const mod of modules) {
     const boundaries: PropagationBoundary[] = []

Diff for: playground/hmr/__tests__/hmr.spec.ts

@@ -154,7 +154,7 @@ if (!isBuild) {
   })
 
   test('invalidate', async () => {
-    const el = await page.$('.invalidation')
+    const el = await page.$('.invalidation-parent')
     await untilBrowserLogAfter(
       () =>
         editFile('invalidation/child.js', (code) =>
@@ -182,7 +182,7 @@ if (!isBuild) {
       page2 = await browser.newPage()
       await page2.goto(viteTestUrl)
 
-      const el = await page.$('.invalidation')
+      const el = await page.$('.invalidation-parent')
       await untilBrowserLogAfter(
         () =>
           editFile('invalidation/child.js', (code) =>
@@ -208,6 +208,15 @@ if (!isBuild) {
     }
   })
 
+  test('invalidate on root triggers page reload', async () => {
+    editFile('invalidation/root.js', (code) => code.replace('Init', 'Updated'))
+    await page.waitForEvent('load')
+    await untilUpdated(
+      async () => (await page.$('.invalidation-root')).textContent(),
+      'Updated',
+    )
+  })
+
   test('soft invalidate', async () => {
     const el = await page.$('.soft-invalidation')
     expect(await el.textContent()).toBe(

Diff for: playground/hmr/hmr.ts

@@ -1,7 +1,6 @@
 import { virtual } from 'virtual:file'
 import { foo as depFoo, nestedFoo } from './hmrDep'
 import './importing-updated'
-import './invalidation/parent'
 import './file-delete-restore'
 import './optional-chaining/parent'
 import './intermediate-file-delete'

Diff for: playground/hmr/index.html

@@ -7,6 +7,7 @@
 </div>
 <button class="virtual-update">update virtual module</button>
 
+<script type="module" src="./invalidation/root.js"></script>
 <script type="module" src="./hmr.ts"></script>
 <style>
   .import-image {
@@ -24,7 +25,8 @@
 <div class="toRemove"></div>
 <div class="virtual"></div>
 <div class="soft-invalidation"></div>
-<div class="invalidation"></div>
+<div class="invalidation-parent"></div>
+<div class="invalidation-root"></div>
 <div class="custom-communication"></div>
 <div class="css-prev"></div>
 <div class="css-post"></div>

Diff for: playground/hmr/invalidation/parent.js

@@ -6,4 +6,4 @@ if (import.meta.hot) {
 
 console.log('(invalidation) parent is executing')
 
-document.querySelector('.invalidation').innerHTML = value
+document.querySelector('.invalidation-parent').innerHTML = value

Diff for: playground/hmr/invalidation/root.js

@@ -0,0 +1,16 @@
+import './parent.js'
+
+if (import.meta.hot) {
+  // Need to accept, to register a callback for HMR
+  import.meta.hot.accept(() => {
+    // Triggers full page reload because no importers
+    import.meta.hot.invalidate()
+  })
+}
+
+const root = document.querySelector('.invalidation-root')
+
+// Non HMR-able behaviour
+if (!root.innerHTML) {
+  root.innerHTML = 'Init'
+}