fix(teleport): don't move teleport children if not mounted

[lichunju1]

close #14701

Problem

When a disabled <Teleport> inside <Suspense> has its mount deferred via pendingMounts (introduced in #14642), component children have vnode.component === null because mountChildren was never called. During Suspense.resolve(), move(pendingBranch) walks the vnode tree and crashes on vnode.component.subTree for these unmounted components.

Reproduction: https://play.vuejs.org/#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

Trigger conditions (all required):

1. <Suspense> wrapping an async component (await in setup)
2. Multi-root template (Fragment)
3. <Teleport disabled> as a root sibling
4. Component child (not element) inside the Teleport

• 3.5.31: no error
• 3.5.32: crash

Fix

Add a null check for vnode.component in the move function before accessing .subTree. Components with null instances are skipped — the deferred mount job handles their placement after Suspense flushes its effects.

Summary by CodeRabbit

Tests

• Added test coverage for Suspense with disabled Teleports containing nested async components, validating fallback display and post-resolution rendering.

Bug Fixes

• Fixed mounting of disabled Teleports within Suspense boundaries during async component resolution.
• Improved teleport movement logic to account for pending mount operations.

[coderabbitai]

📝 Walkthrough

Walkthrough

Fixes a regression in Vue 3.5.32 where disabled Teleports containing component children inside Suspense-wrapped async components cause null reference errors. Modifies Teleport's deferred mount logic to use parentNode for correct container selection during Suspense resolution and prevents moving children when in pendingMounts state.

Changes

Cohort / File(s)	Summary
Test Case packages/runtime-core/__tests__/components/Suspense.spec.ts	Adds test for async component with multi-root template containing a disabled Teleport with component child; verifies fallback renders during pending state and content renders correctly after resolution.
Teleport Mount & Move Logic packages/runtime-core/src/components/Teleport.ts	Extended internals.o with parentNode operation; modified deferred mount container selection to use `parentNode(vnode.el!)

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• fix(teleport): handle updates before deferred mount #14642: Directly caused this regression; prior changes to deferred/queued Teleport mount logic that introduced the null reference bug with component children.
• fix(teleport): should not mount deferred teleport after unmount #14598: Also modifies Teleport's deferred mount logic to prevent incorrect mounts after Suspense resolution.
• fix(teleport): properly handling disabled teleport target anchor #14417: Modifies disabled-teleport handling in the same file (anchor/mount preparation for disabled Teleports).

Suggested labels

scope: teleport, scope: suspense, :hammer: p3-minor-bug

Poem

🐰 A teleport hung suspended in time,
When Suspense resolved, oh what a crime!
But parentNode whispers: "Follow me home,"
Now children mount safely, no more do they roam! ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% 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.
Linked Issues check	✅ Passed	The PR addresses the primary objective from #14701: preventing the TypeError crash during Suspense.resolve() by guarding against null component instances, and includes the requested test case and fixes the stale container reference in deferred mount.
Out of Scope Changes check	✅ Passed	All changes are scoped to fixing the regression: test case for the regression, null component check in move function, pendingMounts guard in moveTeleport, and stale container reference fix in deferred mount.
Title check	✅ Passed	The PR title 'fix(teleport): don't move teleport children if not mounted' directly addresses the core fix: preventing movement of teleport children that lack mounted component instances, matching the main change in Teleport.ts.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[edison1105]

Could you please add a test case?

[lichunju1]

Could you please add a test case?

Done — added a test case and also fixed the stale container reference in the deferred mount job. Please take a look.

[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	105 kB (+45 B)	39.9 kB (+22 B)	35.8 kB (+8 B)
vue.global.prod.js	164 kB (+45 B)	59.9 kB (+19 B)	53.2 kB (+6 B)

Usages

Name	Size	Gzip	Brotli
createApp (CAPI only)	48.3 kB	18.8 kB	17.2 kB
createApp	56.5 kB	21.8 kB	20 kB
createSSRApp	60.7 kB	23.6 kB	21.5 kB
defineCustomElement	62.6 kB	23.8 kB	21.7 kB
overall	71 kB	27.2 kB	24.7 kB

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commit: 0d767cd

[edison1105]

Thanks for the PR.
The proper fix should avoid moving teleport children if in the pending mount.
see 0d767cd

[edison1105]

/ecosystem-ci run

[lichunju1]

Thanks for the PR. The proper fix should avoid moving teleport children if in the pending mount. see 0d767cd

Thanks for the refinement! Guarding at the moveTeleport entry is a more precise fix. Learned a lot from this PR.

[vue-bot]

📝 Ran ecosystem CI: Open

suite	result	latest scheduled
language-tools	❌ failure	❌ failure
primevue	✅ success	✅ success
nuxt	✅ success	✅ success
pinia	✅ success	✅ success
quasar	✅ success	✅ success
vant	✅ success	✅ success
router	✅ success	✅ success
vitepress	✅ success	✅ success
radix-vue	✅ success	✅ success
test-utils	✅ success	✅ success
vite-plugin-vue	✅ success	✅ success
vueuse	✅ success	✅ success
vue-macros	✅ success	✅ success
vue-i18n	✅ success	✅ success
vuetify	✅ success	✅ success
vue-simple-compiler	✅ success	✅ success