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fix(hmr): handle cached text node update #14134

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c70913b
fix(hmr): handle text node creation during HMR updates for cached nodes
edison1105 Nov 24, 2025
7e08418
fix: improve HMR updates for cached text nodes by replacing them
edison1105 Nov 25, 2025
6c11c4d
test: add test
edison1105 Nov 25, 2025
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53 changes: 53 additions & 0 deletions packages/runtime-core/__tests__/hmr.spec.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -1040,4 +1040,57 @@ describe('hot module replacement', () => {

expect(serializeInner(root)).toBe('<div>bar</div>')
})

// #14127
test('update cached text nodes', async () => {
const root = nodeOps.createElement('div')
const appId = 'test-cached-text-nodes'
const App: ComponentOptions = {
__hmrId: appId,
data() {
return {
count: 0,
}
},
render: compileToFunction(
`{{count}}
<button @click="count++">++</button>
static text`,
),
}
createRecord(appId, App)
render(h(App), root)
expect(serializeInner(root)).toBe(`0 <button>++</button> static text`)

// trigger count update
triggerEvent((root as any).children[2], 'click')
await nextTick()
expect(serializeInner(root)).toBe(`1 <button>++</button> static text`)

// trigger HMR update
rerender(
appId,
compileToFunction(
`{{count}}
<button @click="count++">++</button>
static text updated`,
),
)
expect(serializeInner(root)).toBe(
`1 <button>++</button> static text updated`,
)

// trigger HMR update again
rerender(
appId,
compileToFunction(
`{{count}}
<button @click="count++">++</button>
static text updated2`,
),
)
expect(serializeInner(root)).toBe(
`1 <button>++</button> static text updated2`,
)
})
})
37 changes: 31 additions & 6 deletions packages/runtime-core/src/renderer.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -500,7 +500,27 @@ function baseCreateRenderer(
} else {
const el = (n2.el = n1.el!)
if (n2.children !== n1.children) {
hostSetText(el, n2.children as string)
// We don't inherit el for cached text nodes in `traverseStaticChildren`
// to avoid retaining detached DOM nodes. However, the text node may be
// changed during HMR. In this case we need to replace the old text node
// with the new one.
if (
__DEV__ &&
isHmrUpdating &&
n2.patchFlag === PatchFlags.CACHED &&
'__elIndex' in n1
) {
const childNodes = __TEST__
? container.children
: container.childNodes
const newChild = hostCreateText(n2.children as string)
const oldChild =
childNodes[((n2 as any).__elIndex = (n1 as any).__elIndex)]
hostInsert(newChild, container, oldChild)
hostRemove(oldChild)
} else {
hostSetText(el, n2.children as string)
}
Comment on lines +503 to +523
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@coderabbitai coderabbitai bot Nov 25, 2025

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⚠️ Potential issue | 🔴 Critical

Critical: n2.el is not updated to reference the new text node.

After creating and inserting newChild (line 516-519), then removing oldChild (line 520), n2.el still points to the old element that was set on line 501. This means n2.el references a detached DOM node after the replacement.

Apply this diff to update n2.el to reference the new text node:

         const newChild = hostCreateText(n2.children as string)
         const oldChild =
           childNodes[((n2 as any).__elIndex = (n1 as any).__elIndex)]
+        n2.el = newChild
         hostInsert(newChild, container, oldChild)
         hostRemove(oldChild)

This follows the pattern used in patchStaticNode (lines 574-584), which properly updates n2.el and n2.anchor after replacing static content during HMR.

📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change
// We don't inherit el for cached text nodes in `traverseStaticChildren`
// to avoid retaining detached DOM nodes. However, the text node may be
// changed during HMR. In this case we need to replace the old text node
// with the new one.
if (
__DEV__ &&
isHmrUpdating &&
n2.patchFlag === PatchFlags.CACHED &&
'__elIndex' in n1
) {
const childNodes = __TEST__
? container.children
: container.childNodes
const newChild = hostCreateText(n2.children as string)
const oldChild =
childNodes[((n2 as any).__elIndex = (n1 as any).__elIndex)]
hostInsert(newChild, container, oldChild)
hostRemove(oldChild)
} else {
hostSetText(el, n2.children as string)
}
// We don't inherit el for cached text nodes in `traverseStaticChildren`
// to avoid retaining detached DOM nodes. However, the text node may be
// changed during HMR. In this case we need to replace the old text node
// with the new one.
if (
__DEV__ &&
isHmrUpdating &&
n2.patchFlag === PatchFlags.CACHED &&
'__elIndex' in n1
) {
const childNodes = __TEST__
? container.children
: container.childNodes
const newChild = hostCreateText(n2.children as string)
const oldChild =
childNodes[((n2 as any).__elIndex = (n1 as any).__elIndex)]
n2.el = newChild
hostInsert(newChild, container, oldChild)
hostRemove(oldChild)
} else {
hostSetText(el, n2.children as string)
}
🤖 Prompt for AI Agents 
In packages/runtime-core/src/renderer.ts around lines 503 to 523, after creating
and inserting newChild and removing oldChild during HMR replace logic, n2.el is
still pointing at the detached old element; update n2 to reference the newly
inserted node (assign n2.el = newChild) and also update n2.anchor if the node
uses an anchor (follow the same assignment pattern as patchStaticNode lines
~574-584) so the vnode now points to the live DOM node.

}
}
}
Expand Down Expand Up @@ -2496,12 +2516,17 @@ export function traverseStaticChildren(
traverseStaticChildren(c1, c2)
}
// #6852 also inherit for text nodes
if (
c2.type === Text &&
if (c2.type === Text) {
// avoid cached text nodes retaining detached dom nodes
c2.patchFlag !== PatchFlags.CACHED
) {
c2.el = c1.el
if (c2.patchFlag !== PatchFlags.CACHED) {
c2.el = c1.el
} else {
// cache the child index for HMR updates
;(c2 as any).__elIndex =
i +
// take fragment start anchor into account
(n1.type === Fragment ? 1 : 0)
}
}
// #2324 also inherit for comment nodes, but not placeholders (e.g. v-if which
// would have received .el during block patch)
Expand Down
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