Fix validation hook merge function passthrough (#9278)

Co-authored-by: Daniel Cousens <413395+dcousens@users.noreply.github.com>

.changeset/fix-hooks-errors.md

@@ -0,0 +1,5 @@
+---
+"@keystone-6/core": patch
+---
+
+Fix blended usage of `{field}.hooks.validateInput` and `{field}.validate.*` resulting in an error

packages/core/src/fields/resolve-hooks.ts

@@ -9,32 +9,6 @@ import {
 export type InternalFieldHooks<ListTypeInfo extends BaseListTypeInfo> =
   Omit<FieldHooks<ListTypeInfo>, 'validateInput' | 'validateDelete' | 'resolveInput'>
 
-/** @deprecated, TODO: remove in breaking change */
-function resolveValidateHooks <ListTypeInfo extends BaseListTypeInfo> ({
-  validate,
-  validateInput,
-  validateDelete
-}: FieldHooks<ListTypeInfo>): Exclude<FieldHooks<ListTypeInfo>["validate"], Function> | undefined {
-  if (validateInput || validateDelete) {
-    return {
-      create: validateInput,
-      update: validateInput,
-      delete: validateDelete,
-    }
-  }
-
-  if (!validate) return
-  if (typeof validate === 'function') {
-    return {
-      create: validate,
-      update: validate,
-      delete: validate
-    }
-  }
-
-  return validate
-}
-
 function merge <
   R,
   A extends (r: R) => MaybePromise<void>,
@@ -47,6 +21,20 @@ function merge <
   }
 }
 
+/** @deprecated, TODO: remove in breaking change */
+function resolveValidateHooks <ListTypeInfo extends BaseListTypeInfo> ({
+  validate,
+  validateInput,
+  validateDelete
+}: FieldHooks<ListTypeInfo>): Exclude<FieldHooks<ListTypeInfo>["validate"], Function> | undefined {
+  if (!validate && !validateInput && !validateDelete) return
+  return {
+    create: merge(validateInput,  typeof validate === 'function' ? validate : validate?.create),
+    update: merge(validateInput,  typeof validate === 'function' ? validate : validate?.update),
+    delete: merge(validateDelete, typeof validate === 'function' ? validate : validate?.delete),
+  }
+}
+
 export function mergeFieldHooks <ListTypeInfo extends BaseListTypeInfo> (
   builtin?: InternalFieldHooks<ListTypeInfo>,
   hooks?: FieldHooks<ListTypeInfo>,
@@ -67,5 +55,9 @@ export function mergeFieldHooks <ListTypeInfo extends BaseListTypeInfo> (
       update: merge(builtinValidate?.update, hooksValidate?.update),
       delete: merge(builtinValidate?.delete, hooksValidate?.delete)
     } : undefined,
+
+    // TODO: remove in breaking change
+    validateInput: undefined, // prevent continuation
+    validateDelete: undefined, // prevent continuation
   } satisfies FieldHooks<ListTypeInfo>
 }