fix: setValidationRule() cannot use with ruleGroup

system/BaseModel.php

@@ -1345,7 +1345,7 @@ public function skipValidation(bool $skip = true)
     }
 
     /**
-     * Allows to set validation messages.
+     * Allows to set (and reset) validation messages.
      * It could be used when you have to change default or override current validate messages.
      *
      * @param array $validationMessages Value
@@ -1376,7 +1376,7 @@ public function setValidationMessage(string $field, array $fieldMessages)
     }
 
     /**
-     * Allows to set validation rules.
+     * Allows to set (and reset) validation rules.
      * It could be used when you have to change default or override current validate rules.
      *
      * @param array $validationRules Value
@@ -1401,6 +1401,17 @@ public function setValidationRules(array $validationRules)
      */
     public function setValidationRule(string $field, $fieldRules)
     {
+        $rules = $this->validationRules;
+
+        // ValidationRules can be either a string, which is the group name,
+        // or an array of rules.
+        if (is_string($rules)) {
+            [$rules, $customErrors] = $this->validation->loadRuleGroup($rules);
+
+            $this->validationRules    = $rules;
+            $this->validationMessages = $this->validationMessages + $customErrors;
+        }
+
         $this->validationRules[$field] = $fieldRules;
 
         return $this;
@@ -1466,7 +1477,9 @@ public function getValidationRules(array $options = []): array
         // ValidationRules can be either a string, which is the group name,
         // or an array of rules.
         if (is_string($rules)) {
-            $rules = $this->validation->loadRuleGroup($rules);
+            [$rules, $customErrors] = $this->validation->loadRuleGroup($rules);
+
+            $this->validationMessages = $this->validationMessages + $customErrors;
         }
 
         if (isset($options['except'])) {

system/Validation/Validation.php

@@ -665,7 +665,7 @@ protected function loadRuleSets()
      * same format used with setRules(). Additionally, check
      * for {group}_errors for an array of custom error messages.
      *
-     * @return array
+     * @return array<int, array> [rules, customErrors]
      *
      * @throws ValidationException
      */
@@ -693,7 +693,7 @@ public function loadRuleGroup(?string $group = null)
             $this->customErrors = $this->config->{$errorName};
         }
 
-        return $this->rules;
+        return [$this->rules, $this->customErrors];
     }
 
     /**

tests/_support/Config/Validation.php

@@ -0,0 +1,32 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <[email protected]>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Tests\Support\Config;
+
+use Config\Validation as ValidationConfig;
+
+class Validation extends ValidationConfig
+{
+    public $signup = [
+        'id'   => 'permit_empty|is_natural_no_zero',
+        'name' => [
+            'required',
+            'min_length[3]',
+        ],
+        'token' => 'permit_empty|in_list[{id}]',
+    ];
+    public $signup_errors = [
+        'name' => [
+            'required'   => 'You forgot to name the baby.',
+            'min_length' => 'Too short, man!',
+        ],
+    ];
+}

tests/_support/Models/ValidModelRuleGroup.php

@@ -0,0 +1,27 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <[email protected]>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Tests\Support\Models;
+
+use CodeIgniter\Model;
+
+class ValidModelRuleGroup extends Model
+{
+    protected $table          = 'job';
+    protected $returnType     = 'object';
+    protected $useSoftDeletes = false;
+    protected $dateFormat     = 'int';
+    protected $allowedFields  = [
+        'name',
+        'description',
+    ];
+    protected $validationRules = 'signup';
+}