[v2] Fix: Keep ArrayField in sync after array replacement

[scttcper]

ArrayField only reacts to array length and _arrayVersion, so replacing an array with a different array of the same length updated form state without rerendering the array container. UI rendered from the array could stay stale while submission used the new values.

This bumps _arrayVersion for direct same-length replacements. Array helpers now rely on length changes or this shared behavior instead of manually updating the version, while nested field updates still avoid rerendering the parent ArrayField.

Summary by CodeRabbit

• Bug Fixes

  • Array fields now update reliably when replaced with a new array of the same length.
  • Array components rerender when their array value changes, while avoiding unnecessary rerenders for nested field updates.
  • Array operations such as swapping, moving, or clearing items now maintain consistent field updates.

• Tests

  • Added coverage for array replacement, updater functions, nested updates, and array helper operations.

[coderabbitai]

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ℹ️ Recent review info

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Run ID: 7561444a-d36e-46ce-a636-be889ad3dab7

📥 Commits

Reviewing files that changed from the base of the PR and between 4ad5a7b and 4f0849d.

📒 Files selected for processing (4)

• packages/form-core/src/FormApi/FormApi.lib.ts
• packages/form-core/src/FormApi/array-methods.lib.ts
• packages/form-core/tests/FormApi/field-state.spec.ts
• packages/react-form/tests/FormField.spec.tsx

💤 Files with no reviewable changes (1)

• packages/form-core/src/FormApi/array-methods.lib.ts

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📝 Walkthrough

Walkthrough

The change centralizes _arrayVersion updates in setFieldValue, removes duplicate notifications from array helpers, and adds core and React tests for array replacement, nested updates, helper operations, and ArrayField rerender behavior.

Changes

Array version tracking

Layer / File(s)	Summary
Centralize array-version updates packages/form-core/src/FormApi/FormApi.lib.ts, packages/form-core/src/FormApi/array-methods.lib.ts	setFieldValue resolves updater values before writing them and increments _arrayVersion for same-length array replacements. Array helpers no longer increment the metadata directly.
Validate array version behavior packages/form-core/tests/FormApi/field-state.spec.ts, packages/react-form/tests/FormField.spec.tsx	Tests cover direct and updater replacements, nested field updates, array helpers, and ArrayField rerender behavior.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to 4f084

The change makes equal-length array replacements rerender correctly while preserving nested field behavior and is merge-ready after normal checks and review; no actionable merge-blocking risk remains.

Suggested reviewers: lecarbonator

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description clearly explains the problem, motivation, and implementation. It omits the required Checklist and Release Impact sections from the repository template.	Add the Checklist section and mark the applicable items. Add the Release Impact section and indicate whether the change requires a changeset or is docs/CI/dev-only.
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 2 functions across 3 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: keeping ArrayField synchronized after array replacement.
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.

• Fix all pre-merge checks with AI

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[scttcper]

this test does fail without the change

[nx-cloud]

View your CI Pipeline Execution ↗ for commit e409b42

Command	Status	Duration	Result
nx affected --targets=test:sherif,test:knip,tes...	⛔ Cancelled	16s	View ↗
nx run-many --target=build --exclude=examples/**	✅ Succeeded	24s	View ↗

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☁️ Nx Cloud last updated this comment at 2026-08-27 10:22:14 UTC