fix: make seeder to respect database group

system/Database/Seeder.php

@@ -27,7 +27,7 @@ class Seeder
     /**
      * The name of the database group to use.
      *
-     * @var non-empty-string
+     * @var non-empty-string|null
      */
     protected $DBGroup;
 
@@ -92,10 +92,16 @@ public function __construct(Database $config, ?BaseConnection $db = null)
 
         $this->config = &$config;
 
-        $db ??= Database::connect($this->DBGroup);
-
-        $this->db    = $db;
-        $this->forge = Database::forge($this->DBGroup);
+        if (isset($this->DBGroup)) {
+            $this->db    = Database::connect($this->DBGroup);
+            $this->forge = Database::forge($this->DBGroup);
+        } elseif ($db instanceof BaseConnection) {
+            $this->db    = $db;
+            $this->forge = Database::forge($db);
+        } else {
+            $this->db    = Database::connect($config->defaultGroup);
+            $this->forge = Database::forge($config->defaultGroup);
+        }
     }
 
     /**
@@ -145,7 +151,7 @@ public function call(string $class)
         }
 
         /** @var Seeder $seeder */
-        $seeder = new $class($this->config);
+        $seeder = new $class($this->config, $this->db);
         $seeder->setSilent($this->silent)->run();
 
         unset($seeder);

tests/_support/Database/Seeds/SeederWithDBGroup.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Tests\Support\Database\Seeds;
+
+use CodeIgniter\Database\BaseConnection;
+use CodeIgniter\Database\Seeder;
+
+/**
+ * Test seeder with explicit DBGroup set.
+ */
+class SeederWithDBGroup extends Seeder
+{
+    protected $DBGroup = 'tests';
+
+    /**
+     * Store the connection used during run() for testing.
+     */
+    public static ?BaseConnection $lastConnection = null;
+
+    public function run(): void
+    {
+        self::$lastConnection = $this->db;
+    }
+
+    /**
+     * Expose the db connection for testing.
+     */
+    public function getDatabase(): BaseConnection
+    {
+        return $this->db;
+    }
+
+    /**
+     * Reset static state for testing.
+     */
+    public static function reset(): void
+    {
+        self::$lastConnection = null;
+    }
+}

tests/_support/Database/Seeds/SeederWithoutDBGroup.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Tests\Support\Database\Seeds;
+
+use CodeIgniter\Database\BaseConnection;
+use CodeIgniter\Database\Seeder;
+
+/**
+ * Test seeder without DBGroup set (should inherit connection).
+ */
+class SeederWithoutDBGroup extends Seeder
+{
+    /**
+     * Store the connection used during run() for testing.
+     */
+    public static ?BaseConnection $lastConnection = null;
+
+    public function run(): void
+    {
+        self::$lastConnection = $this->db;
+    }
+
+    /**
+     * Expose the db connection for testing.
+     */
+    public function getDatabase(): BaseConnection
+    {
+        return $this->db;
+    }
+
+    /**
+     * Reset static state for testing.
+     */
+    public static function reset(): void
+    {
+        self::$lastConnection = null;
+    }
+}

tests/system/Database/DatabaseSeederTest.php

@@ -17,13 +17,23 @@
 use Config\Database;
 use Faker\Generator;
 use PHPUnit\Framework\Attributes\Group;
+use Tests\Support\Database\Seeds\SeederWithDBGroup;
+use Tests\Support\Database\Seeds\SeederWithoutDBGroup;
 
 /**
  * @internal
  */
-#[Group('Others')]
+#[Group('DatabaseLive')]
 final class DatabaseSeederTest extends CIUnitTestCase
 {
+    protected function tearDown(): void
+    {
+        parent::tearDown();
+
+        SeederWithDBGroup::reset();
+        SeederWithoutDBGroup::reset();
+    }
+
     public function testInstantiateNoSeedPath(): void
     {
         $this->expectException('InvalidArgumentException');
@@ -57,4 +67,60 @@ public function testCallOnEmptySeeder(): void
         $seeder = new Seeder(new Database());
         $seeder->call('');
     }
+
+    public function testSeederWithDBGroupUsesOwnConnection(): void
+    {
+        $config = new Database();
+        $db     = Database::connect('tests', false);
+
+        $seeder = new SeederWithDBGroup($config, $db);
+
+        $testsDb = Database::connect('tests');
+        $this->assertSame($testsDb, $seeder->getDatabase());
+        $this->assertNotSame($db, $seeder->getDatabase());
+    }
+
+    public function testSeederWithoutDBGroupUsesPassedConnection(): void
+    {
+        $config = new Database();
+        $db     = Database::connect('tests');
+
+        $seeder = new SeederWithoutDBGroup($config, $db);
+
+        $this->assertSame($db, $seeder->getDatabase());
+    }
+
+    public function testSeederWithoutDBGroupAndNoConnectionUsesDefault(): void
+    {
+        $config = new Database();
+
+        $seeder = new SeederWithoutDBGroup($config);
+
+        $defaultDb = Database::connect($config->defaultGroup);
+        $this->assertSame($defaultDb, $seeder->getDatabase());
+    }
+
+    public function testCallPassesConnectionToChildSeeder(): void
+    {
+        $config = new Database();
+        $db     = Database::connect('tests');
+
+        $seeder = new Seeder($config, $db);
+        $seeder->setSilent(true)->call(SeederWithoutDBGroup::class);
+
+        $this->assertSame($db, SeederWithoutDBGroup::$lastConnection);
+    }
+
+    public function testCallChildWithDBGroupUsesOwnConnection(): void
+    {
+        $config = new Database();
+        $db     = Database::connect('tests', false);
+
+        $seeder = new Seeder($config, $db);
+        $seeder->setSilent(true)->call(SeederWithDBGroup::class);
+
+        $testsDb = Database::connect('tests');
+        $this->assertSame($testsDb, SeederWithDBGroup::$lastConnection);
+        $this->assertNotSame($db, SeederWithDBGroup::$lastConnection);
+    }
 }

user_guide_src/source/changelogs/v4.6.5.rst

@@ -30,6 +30,8 @@ Deprecations
 Bugs Fixed
 **********
 
+- **Database:** Fixed a bug where ``Seeder::call()`` did not pass the database connection to child seeders, causing them to use the default connection instead of the one specified via ``Database::seeder('group')``.
+
 See the repo's
 `CHANGELOG.md <https://github.com/codeigniter4/CodeIgniter4/blob/develop/CHANGELOG.md>`_
 for a complete list of bugs fixed.

user_guide_src/source/dbmgmt/seeds.rst

@@ -44,6 +44,29 @@ You can grab a copy of the main seeder through the database config class:
 
 .. literalinclude:: seeds/004.php
 
+Using a Different Database Group
+================================
+
+You can specify a different database group when obtaining a seeder instance by passing the group name
+as the first parameter:
+
+.. literalinclude:: seeds/005.php
+
+When using ``call()`` to run child seeders, the database connection is automatically passed to them.
+This means child seeders will use the same connection as the parent seeder, unless they explicitly
+specify their own ``$DBGroup`` property.
+
+If a seeder needs to always use a specific database group regardless of the parent seeder's connection,
+you can set the ``$DBGroup`` property in the seeder class:
+
+.. literalinclude:: seeds/006.php
+
+The connection priority is:
+
+1. If ``$DBGroup`` is set in the seeder class, that connection group is always used
+2. Otherwise, if a connection was passed (from parent seeder via ``call()`` or from ``Database::seeder()``), it is used
+3. Otherwise, the default connection group is used
+
 Command Line Seeding
 ====================
 

user_guide_src/source/dbmgmt/seeds/005.php

@@ -0,0 +1,4 @@
+<?php
+
+$seeder = \Config\Database::seeder('group_name');
+$seeder->call('TestSeeder');

user_guide_src/source/dbmgmt/seeds/006.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace App\Database\Seeds;
+
+use CodeIgniter\Database\Seeder;
+
+class UserSeeder extends Seeder
+{
+    protected $DBGroup = 'group_name';
+
+    public function run()
+    {
+        // ...
+    }
+}