Closes #1242

Problem

A field-level onSubmit error is wrongly cleared when the user focuses and blurs the field without changing its value. The submit error should only disappear once the user actually enters a (valid) value.

Root cause

In FieldApi, the logic that clears a stored submit error fired for any cause other than 'submit':

this.state.meta.errorMap?.[submitErrKey] &&
cause !== 'submit' &&
!hasErrored

handleBlur runs validation with cause: 'blur', which satisfied cause !== 'submit', so a plain blur (no edit) cleared the submit error.

Fix

Clear the stored submit error only on an actual value change:

cause === 'change' &&

A blur (or any non-value cause) no longer drops the submit error. Entering a valid value still clears it as documented.

Tests

Two tests added to packages/form-core/tests/FieldApi.spec.ts:

• should not clear onSubmit errors on blur when the value did not change — fails on main, passes with the fix
• should clear onSubmit errors once a valid value is entered — guards the documented clear-on-change path

Full form-core suite green (107 tests).

Summary by CodeRabbit

• Bug Fixes

  • Fixed form validation to properly preserve submit errors during blur and non-value interactions. Submit errors are now cleared only when valid values are entered, improving form error feedback accuracy.

• Tests

  • Extended test coverage for submit error behavior, verifying errors persist on blur without changes and clear when valid values are entered.