From 571b05bcce14a89395c8e85ce1c0897b04be3d24 Mon Sep 17 00:00:00 2001
From: kenjis <kenji.uui@gmail.com>
Date: Tue, 15 Aug 2023 05:41:40 +0900
Subject: [PATCH 1/2] test: add test for set_checkbox()

---
 tests/system/Helpers/FormHelperTest.php | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/tests/system/Helpers/FormHelperTest.php b/tests/system/Helpers/FormHelperTest.php
index 639d03c48f..ca90ce53c1 100644
--- a/tests/system/Helpers/FormHelperTest.php
+++ b/tests/system/Helpers/FormHelperTest.php
@@ -867,6 +867,29 @@ final class FormHelperTest extends CIUnitTestCase
         $this->assertSame(' checked="checked"', set_checkbox('foo', '0', true));
     }
 
+    /**
+     * @see https://github.com/codeigniter4/CodeIgniter4/issues/7814
+     */
+    public function testSetCheckboxWithUnchecked(): void
+    {
+        $_SESSION = [
+            '_ci_old_input' => [
+                'post' => [
+                ],
+            ],
+        ];
+
+        $this->assertSame(
+            '',
+            set_checkbox('fruit', 'apple', true)
+        );
+
+        $this->assertSame(
+            '',
+            set_checkbox('fruit', 'apple')
+        );
+    }
+
     /**
      * @runInSeparateProcess
      * @preserveGlobalState disabled

From f2f7dcf22366fdd145406b955335b734007e891e Mon Sep 17 00:00:00 2001
From: kenjis <kenji.uui@gmail.com>
Date: Tue, 15 Aug 2023 05:42:33 +0900
Subject: [PATCH 2/2] fix: set_checkbox() incorrect checking

set_checkbox() with default true checks unchecked checkbox
when redirected back with input.
---
 system/Helpers/form_helper.php | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/system/Helpers/form_helper.php b/system/Helpers/form_helper.php
index c553bddee2..7f8f191a3a 100644
--- a/system/Helpers/form_helper.php
+++ b/system/Helpers/form_helper.php
@@ -629,8 +629,11 @@ if (! function_exists('set_checkbox')) {
             return '';
         }
 
+        $session     = Services::session();
+        $hasOldInput = $session->has('_ci_old_input');
+
         // Unchecked checkbox and radio inputs are not even submitted by browsers ...
-        if ((string) $input === '0' || ! empty($request->getPost()) || ! empty(old($field))) {
+        if ((string) $input === '0' || ! empty($request->getPost()) || $hasOldInput) {
             return ($input === $value) ? ' checked="checked"' : '';
         }