From 26714450ff97fe16130f127c54bd7f8db0581726 Mon Sep 17 00:00:00 2001
From: Bogdan <matolq@gmail.com>
Date: Fri, 19 Jun 2026 21:31:54 +0200
Subject: [PATCH] fix(Validation): correct required_without logic and prevent
 array key warnings

---
 system/Validation/Rules.php                | 15 +++++++++++----
 tests/system/Validation/ValidationTest.php | 22 ++++++++++++++++++++++
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/system/Validation/Rules.php b/system/Validation/Rules.php
index e3e256b099b4..69bc6e5ea2e6 100644
--- a/system/Validation/Rules.php
+++ b/system/Validation/Rules.php
@@ -429,15 +429,22 @@ public function required_without(
 
                 $fieldData       = dot_array_search($otherField, $data);
                 $fieldSplitArray = explode('.', $field);
-                $fieldKey        = $fieldSplitArray[1];
+                $fieldKey        = $fieldSplitArray[1] ?? null;
 
                 if (is_array($fieldData)) {
-                    return ! empty(dot_array_search($otherField, $data)[$fieldKey]);
+                    if (empty($fieldData[$fieldKey])) {
+                        return false;
+                    }
+
+                    continue;
                 }
-                $nowField      = str_replace('*', $fieldKey, $otherField);
+
+                $nowField      = str_replace('*', (string) $fieldKey, $otherField);
                 $nowFieldVaule = dot_array_search($nowField, $data);
 
-                return null !== $nowFieldVaule;
+                if (null === $nowFieldVaule) {
+                    return false;
+                }
             }
         }
 
diff --git a/tests/system/Validation/ValidationTest.php b/tests/system/Validation/ValidationTest.php
index 7e0f4411f079..48c92aea3968 100644
--- a/tests/system/Validation/ValidationTest.php
+++ b/tests/system/Validation/ValidationTest.php
@@ -1854,6 +1854,28 @@ public function testRequireWithoutWithAsterisk(): void
         );
     }
 
+    /**
+     * Test that `required_without` checks all fields in dot-notation when there are multiple fields.
+     */
+    public function testRequireWithoutMultipleWithAsterisk(): void
+    {
+        $data = [
+            'a' => [
+                ['b' => 1, 'c' => 2, 'd' => ''],
+                ['b' => 1, 'c' => '', 'd' => ''],
+            ],
+        ];
+
+        $this->validation->setRules([
+            'a.*.d' => 'required_without[a.*.b,a.*.c]',
+        ])->run($data);
+
+        $this->assertSame(
+            'The a.*.d field is required when a.*.b,a.*.c is not present.',
+            $this->validation->getError('a.1.d'),
+        );
+    }
+
     /**
      * @see https://github.com/codeigniter4/CodeIgniter4/issues/8128
      */