fix(form-core): prioritize StandardSchemaV1 check over FieldValidateFn for callable schemas (fixes #2221)

packages/form-core/src/types.ts

@@ -452,17 +452,17 @@ export type UnwrapFieldValidateOrFn<
             : undefined
           : undefined
       : never)
-  | ([TValidateOrFn] extends [FieldValidateFn<any, any, any>]
-      ? ReturnType<TValidateOrFn>
-      : [TValidateOrFn] extends [StandardSchemaV1<any, any>]
-        ? // TODO: Check if `disableErrorFlat` is enabled, if so, return StandardSchemaV1Issue[][]
-          StandardSchemaV1Issue[]
+  | ([TValidateOrFn] extends [StandardSchemaV1<any, any>]
+      ? // TODO: Check if `disableErrorFlat` is enabled, if so, return StandardSchemaV1Issue[][]
+        StandardSchemaV1Issue[]
+      : [TValidateOrFn] extends [FieldValidateFn<any, any, any>]
+        ? ReturnType<TValidateOrFn>
         : undefined)
-  | ([TValidateOrFn] extends [FormGroupValidateFn<any, any, any>]
-      ? ReturnType<TValidateOrFn>
-      : [TValidateOrFn] extends [StandardSchemaV1<any, any>]
-        ? // TODO: Check if `disableErrorFlat` is enabled, if so, return StandardSchemaV1Issue[][]
-          StandardSchemaV1Issue[]
+  | ([TValidateOrFn] extends [StandardSchemaV1<any, any>]
+      ? // TODO: Check if `disableErrorFlat` is enabled, if so, return StandardSchemaV1Issue[][]
+        StandardSchemaV1Issue[]
+      : [TValidateOrFn] extends [FormGroupValidateFn<any, any, any>]
+        ? ReturnType<TValidateOrFn>
         : undefined)
 
 /**

packages/form-core/tests/standardSchemaValidator.test-d.ts

@@ -1,5 +1,6 @@
 import { describe, expectTypeOf, it } from 'vitest'
 import { z } from 'zod'
+import { type } from 'arktype'
 import { FieldApi, FormApi, standardSchemaValidators } from '../src/index'
 import type { StandardSchemaV1Issue } from '../src/index'
 
@@ -80,6 +81,27 @@ describe('standard schema validator', () => {
     >()
   })
 
+  it('Should infer StandardSchemaV1Issue[] for arktype field validators (issue #2221)', () => {
+    const schema = type({ firstName: 'string>0' })
+    const form = new FormApi({
+      defaultValues: {
+        firstName: '',
+      },
+    })
+
+    const field = new FieldApi({
+      form,
+      name: 'firstName',
+      validators: {
+        onChange: type('string>0'),
+      },
+    })
+
+    expectTypeOf(field.getMeta().errorMap.onChange).toEqualTypeOf<
+      undefined | StandardSchemaV1Issue[]
+    >()
+  })
+
   it('Should return different Standard Schema Issue types from validateAsync based on scope', () => {
     const formSourceError = standardSchemaValidators.validateAsync(
       { value: '', validationSource: 'form' },