test(form-core): cover onMount field errors before field mount by cyphercodes · Pull Request #2223 · TanStack/form

cyphercodes · 2026-06-25T03:19:16Z

Refs #1366

🎯 Changes

Adds regression coverage for a form-level validators.onMount returning field errors before the corresponding field has mounted.
Verifies a subsequently mounted FieldApi receives the onMount field error, records the error source as form, and exposes the flattened error list.

✅ Checklist

I have followed the steps in the Contributing guide.
I have tested this code locally with pnpm test:pr.

🚀 Release Impact

This change affects published code, and I have generated a changeset.
This change is docs/CI/dev-only (no release).

Summary by CodeRabbit

Tests
- Added regression coverage to ensure fields mounted after form initialization preserve form-level validation errors, including their source and aggregated error state.

coderabbitai · 2026-06-25T03:19:32Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: d2dac42d-9c07-494a-b3f3-af43465d8675

📥 Commits

Reviewing files that changed from the base of the PR and between 225878f and 59fec98.

📒 Files selected for processing (1)

packages/form-core/tests/FormApi.spec.ts

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

packages/form-core/tests/FormApi.spec.ts

Included review availability: Your plan includes up to 8 reviews per rolling hour; 7 remain after this review.

📝 Walkthrough

Walkthrough

Adds a regression test for a field mounted after form mount. The test verifies that a form-level onMount validator error remains available on the field, including its source and aggregated error list.

Changes

Form mount error retention

Layer / File(s)	Summary
Late field mount error assertions `packages/form-core/tests/FormApi.spec.ts`	Adds a test that mounts the form before the field and verifies the retained field error, its `"form"` source, and the aggregated `errors` list.

Estimated code review effort: 1 (Trivial) | ~2 minutes

Merge Risk: ⚪ Minimal · up to 59fec

This PR adds regression coverage for form-level onMount field errors without changing published behavior or runtime configuration; no actionable merge-blocking risk remains beyond normal checks and review.

Possibly related issues

Field validation errors returned by the onMount validator never make it to the Field instance #1366 — The test directly covers the FormApi behavior described by this issue.

Possibly related PRs

TanStack/form#2333 — The test exercises form-level mount-validator field errors and their source handling.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description includes the required changes, checklist, release impact, testing status, and issue reference.
Title check	✅ Passed	The title clearly and concisely describes the regression test for form-level onMount field errors before field mount.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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.

✨ Finishing Touches

🧪 Generate unit tests (beta)

Create PR with unit tests

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LeCarbonator

LGTM! Thanks!

nx-cloud · 2026-08-17T06:03:16Z

View your CI Pipeline Execution ↗ for commit 59fec98

Command	Status	Duration	Result
`nx affected --targets=test:sherif,test:knip,tes...`	✅ Succeeded	3m 4s	View ↗
`nx run-many --target=build --exclude=examples/**`	✅ Succeeded	1s	View ↗

☁️ Nx Cloud last updated this comment at 2026-08-17 06:07:10 UTC

pkg-pr-new · 2026-08-17T06:04:24Z

More templates

@tanstack/angular-form

npm i https://pkg.pr.new/@tanstack/angular-form@2223

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@tanstack/react-form-nextjs

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commit: 59fec98

codecov-commenter · 2026-08-17T06:07:39Z

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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.78%. Comparing base (6892ed0) to head (59fec98).
⚠️ Report is 273 commits behind head on main.
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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2223      +/-   ##
==========================================
- Coverage   90.35%   89.78%   -0.57%     
==========================================
  Files          38       66      +28     
  Lines        1752     3232    +1480     
  Branches      444      812     +368     
==========================================
+ Hits         1583     2902    +1319     
- Misses        149      296     +147     
- Partials       20       34      +14

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test(form-core): cover onMount field errors before field mount

225878f

coderabbitai Bot mentioned this pull request Aug 13, 2026

chore: split up validator file for clarity #2334

Merged

LeCarbonator approved these changes Aug 17, 2026

View reviewed changes

Merge branch 'main' into fix/onmount-field-errors-1366

59fec98

LeCarbonator merged commit 57a855b into TanStack:main Aug 17, 2026
9 checks passed

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test(form-core): cover onMount field errors before field mount - #2223

test(form-core): cover onMount field errors before field mount#2223
LeCarbonator merged 2 commits into
TanStack:mainfrom
cyphercodes:fix/onmount-field-errors-1366

cyphercodes commented Jun 25, 2026 •

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cyphercodes commented Jun 25, 2026 •

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