fix(runtime-core): force model update when reverted before sync (fix #13524)

[liulinboyi]

fix #13524 defineModel on Firefox does not work as expected

Summary by CodeRabbit

• Bug Fixes

  • Improved model handling during rapid consecutive input events so local input values stay consistent when an intermediate value is reverted before parent updates apply.

• Tests

  • Added a test verifying model behavior and render counts when an intermediate model value is reverted prior to parent update propagation.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: c84e7957-883a-4c15-b95d-33455017f5ba

📥 Commits

Reviewing files that changed from the base of the PR and between 10c80c8 and 5736a04.

📒 Files selected for processing (1)

• packages/runtime-core/src/helpers/useModel.ts

🚧 Files skipped from review as they are similar to previous changes (1)

• packages/runtime-core/src/helpers/useModel.ts

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📝 Walkthrough

Walkthrough

Expands useModel.set to detect a microtask-ordering edge where an intermediate emitted value is reverted before parent prop updates flush; adds a test reproducing the rapid onModelInput→onInput sequence and asserting post-nextTick stability.

Changes

useModel microtask timing

Layer / File(s)	Summary
useModel setter microtask edge case packages/runtime-core/src/helpers/useModel.ts	Refactors parent v-model detection into a computed hasVModel and expands the forced-local-update predicate to also trigger when the value changed since the previous set but the emitted value still equals the current local value, ensuring DOM resync in microtask-timing reversion scenarios.
Microtask reversion test case packages/runtime-core/__tests__/helpers/useModel.spec.ts	Adds test #13524 that mounts a parent/child useModel setup, quickly emits onModelInput then onInput to revert an intermediate value, and asserts that after nextTick the model, DOM, and render counts are stable and as expected.

Sequence Diagram

sequenceDiagram
  participant Parent
  participant Child
  participant useModel
  participant DOM

  Parent->>Child: pass modelValue (initial)
  Child->>useModel: mount with modelValue
  useModel->>DOM: render initial

  Note over Child,useModel: rapid listener sequence (microtask ordering)
  Child->>useModel: onModelInput(intermediate)
  useModel->>Parent: emit update: intermediate
  useModel->>DOM: schedule local update (intermediate)

  Child->>useModel: onInput(revert to initial)
  useModel->>Parent: emit update: initial
  useModel->>DOM: schedule local update (initial)

  Note over useModel,Parent: parent prop may still be initial (no flushed update)
  useModel->>useModel: detect changed vs prevSetValue && emittedValue == localValue
  useModel->>DOM: force trigger() to ensure DOM sync

Loading

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 Microtasks leapt and values twirled,
A blink, a revert, the DOM unfurled,
I nudge a trigger, steady the race,
Now useModel keeps its rightful place.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: fixing a model update issue when a value is reverted before synchronization, directly addressing issue #13524.
Linked Issues check	✅ Passed	The PR adds a test case and fixes the useModel logic to handle a specific timing scenario where an intermediate model value is reverted before parent updates flush, directly addressing the Firefox defineModel issue in #13524.
Out of Scope Changes check	✅ Passed	All changes are focused on fixing the defineModel timing issue: a new test verifying the revert behavior and modifications to useModel logic to force updates in the specific revert scenario.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	106 kB (+29 B)	40.1 kB (+15 B)	36 kB (-24 B)
vue.global.prod.js	164 kB (+29 B)	60.1 kB (+17 B)	53.4 kB (-45 B)

Usages

Name	Size	Gzip	Brotli
createApp (CAPI only)	48.8 kB	19 kB	17.4 kB
createApp	56.9 kB	22 kB	20.1 kB
createSSRApp	61.2 kB	23.8 kB	21.7 kB
defineCustomElement	63.1 kB	23.9 kB	21.8 kB
overall	71.7 kB	27.4 kB	25 kB

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commit: 5736a04

[edison1105]

/ecosystem-ci run

[vue-bot]

📝 Ran ecosystem CI: Open

suite	result	latest scheduled
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language-tools	✅ success	✅ success
router	✅ success	✅ success
vitepress	✅ success	✅ success
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vueuse	✅ success	✅ success
primevue	✅ success	✅ success
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vue-simple-compiler	✅ success	✅ success
vite-plugin-vue	✅ success	✅ success
vue-macros	✅ success	✅ success