refactor(vapor): split NON_STABLE slot marker out of VaporSlotFlags

[edison1105]

Summary by CodeRabbit

• New Features

  • Improved forwarded-slot handling across Vapor and VDOM interoperability.
  • Added faster rendering for eligible stable slot content.
  • Improved fallback ownership and boundary behavior for nested slots.

• Bug Fixes

  • Fixed hydration anchors and updates for nested forwarded slots.
  • Improved slot behavior with teleportation, cloned components, custom elements, and scope IDs.

• Refactor

  • Simplified slot configuration into unified flags, improving consistency across rendering paths.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Team

Run ID: f581d903-1c89-4f4d-859a-97aeb0357e20

📥 Commits

Reviewing files that changed from the base of the PR and between b79d0f0 and d671254.

📒 Files selected for processing (2)

• packages/compiler-vapor/src/generators/component.ts
• packages/compiler-vapor/src/generators/if.ts

Included review availability: Your plan provides up to 10 included reviews per hour; 7 remain after this review.

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📝 Walkthrough

Walkthrough

Vapor slot handling now uses encoded forwarding and fallback flags with separate stability metadata. Compiler output, VDOM interop, runtime fragments, boundary tracking, hydration, scope IDs, and tests were updated.

Changes

Vapor slot flags and boundary handling

Layer / File(s)	Summary
Flag contract and compiler emission packages/shared/src/vaporFlags.ts, packages/runtime-core/src/apiCreateApp.ts, packages/compiler-vapor/src/generators/*, packages/compiler-vapor/__tests__/transforms/vSlot.spec.ts	Slot flags now use FORWARDED and SHARED_FALLBACK. Slot stability uses VaporSlotStability.NON_STABLE. Compiler generators share flag serialization. VDOM slot options now use a numeric flags property.
Slot fragment runtime model packages/runtime-vapor/src/componentSlots.ts, packages/runtime-vapor/src/fragment.ts, packages/runtime-vapor/src/fragmentFlags.ts	Slot creation and SlotFragment construction now use encoded flags. SLOT_RESOLVER identifies fragments that perform slot resolution. Fast-path fragments clear their slot boundary.
VDOM interop boundary flow packages/runtime-vapor/src/vdomInterop.ts, packages/runtime-vapor/src/vdomInteropState.ts	VDOM slot interop derives boundary behavior from decoded flags. Content boundaries separate arbitrating outlets from fast-path outlets. Slot ownership uses isSlotResolver.
Slot behavior validation packages/runtime-vapor/__tests__/*	Tests cover forwarded slots, fallback ownership, fast-path rendering, hydration anchors, scope IDs, teleportation, and stability markers.

Estimated code review effort: 4 (Complex) | ~45 minutes

Merge Risk: ⚪ Minimal · up to d6712

This refactor has no actionable merge-blocking risk at the current head and is merge-ready after normal checks and review.

Sequence Diagram(s)

sequenceDiagram
  participant VDOMSlot
  participant VaporSlotFlags
  participant ComponentSlots
  participant SlotFragment
  participant DynamicFragment
  VDOMSlot->>VaporSlotFlags: Decode forwarding and fallback flags
  VDOMSlot->>ComponentSlots: Pass flags and content boundary
  ComponentSlots->>SlotFragment: Create fragment when fallback arbitration is required
  ComponentSlots->>DynamicFragment: Create fast-path fragment otherwise
  DynamicFragment-->>VDOMSlot: Render content outside the slot boundary

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🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 13.33% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 30 functions across 19 files.	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	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly and concisely describes the central change: moving the NON_STABLE slot marker out of VaporSlotFlags into a separate stability enum. This change is reflected across the compiler, runt…

Full details: Title check

Explanation

The title clearly and concisely describes the central change: moving the NON_STABLE slot marker out of VaporSlotFlags into a separate stability enum. This change is reflected across the compiler, runtime, shared flags, and tests.

• Fix all pre-merge checks with AI

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch edison/refactor/slots

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commit: d671254

[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
compiler-dom.global.prod.js	87.2 kB	30.6 kB	26.9 kB
runtime-dom.global.prod.js	117 kB	43.8 kB	39.2 kB
vue.global.prod.js	177 kB	64 kB	57 kB

Usages

Name	Size	Gzip	Brotli
createApp (CAPI only)	53.3 kB	20.7 kB	18.9 kB
createApp	62.3 kB	24 kB	21.8 kB
createApp + vaporInteropPlugin	118 kB (+147 B)	42.7 kB (+39 B)	38.4 kB (+70 B)
createVaporApp	30.8 kB	11.8 kB	10.8 kB
createSSRApp	67.5 kB	26.1 kB	23.6 kB
createVaporSSRApp	36.6 kB	13.9 kB	12.8 kB
defineCustomElement	69 kB	26 kB	23.7 kB
defineVaporCustomElement	46.6 kB	16.9 kB	15.5 kB
overall	77.7 kB	29.5 kB	26.7 kB