diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/cache.php b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/cache.php
index 8b443c3c98eee..a63d2fa67660e 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/cache.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/cache.php
@@ -1,65 +1,85 @@
 <?php
 
-$container->loadFromExtension('framework', [
-    'annotations' => false,
-    'http_method_override' => false,
-    'handle_all_throwables' => true,
-    'php_errors' => ['log' => true],
-    'cache' => [
-        'pools' => [
-            'cache.foo' => [
-                'adapter' => 'cache.adapter.apcu',
-                'default_lifetime' => 30,
-            ],
-            'cache.baz' => [
-                'adapter' => 'cache.adapter.filesystem',
-                'default_lifetime' => 7,
-            ],
-            'cache.foobar' => [
-                'adapter' => 'cache.adapter.psr6',
-                'default_lifetime' => 10,
-                'provider' => 'app.cache_pool',
-            ],
-            'cache.def' => [
-                'default_lifetime' => 'PT11S',
-            ],
-            'cache.expr' => [
-                'default_lifetime' => '13 seconds',
-            ],
-            'cache.chain' => [
-                'default_lifetime' => 12,
-                'adapter' => [
-                    'cache.adapter.array',
-                    'cache.adapter.filesystem',
-                    'redis://foo' => 'cache.adapter.redis',
+namespace Symfony\Component\DependencyInjection\Loader\Configurator;
+
+use Symfony\Component\Cache\Adapter\ChainAdapter;
+
+return static function (ContainerConfigurator $container) {
+    $services = $container->services()
+        ->defaults()
+            ->autowire(true)
+            ->autoconfigure(true)
+    ;
+
+    $services->set('chain_cache_custom_ns', ChainAdapter::class)
+        ->arg(0, ['cache.adapter.array', 'cache.adapter.filesystem'])
+        ->tag('cache.pool', ['namespace' => 'my-custom-ns']);
+
+    $container->extension('framework', [
+        'annotations' => false,
+        'http_method_override' => false,
+        'handle_all_throwables' => true,
+        'php_errors' => ['log' => true],
+        'cache' => [
+            'pools' => [
+                'cache.foo' => [
+                    'adapter' => 'cache.adapter.apcu',
+                    'default_lifetime' => 30,
+                ],
+                'cache.baz' => [
+                    'adapter' => 'cache.adapter.filesystem',
+                    'default_lifetime' => 7,
+                ],
+                'cache.foobar' => [
+                    'adapter' => 'cache.adapter.psr6',
+                    'default_lifetime' => 10,
+                    'provider' => 'app.cache_pool',
+                ],
+                'cache.def' => [
+                    'default_lifetime' => 'PT11S',
+                ],
+                'cache.expr' => [
+                    'default_lifetime' => '13 seconds',
+                ],
+                'cache.chain' => [
+                    'default_lifetime' => 12,
+                    'adapter' => [
+                        'cache.adapter.array',
+                        'cache.adapter.filesystem',
+                        'redis://foo' => 'cache.adapter.redis',
+                    ],
+                ],
+                'cache.custom_ns_chain' => [
+                    'default_lifetime' => 12,
+                    'adapters' => ['chain_cache_custom_ns'],
+                ],
+                'cache.ccc' => [
+                    'adapter' => 'cache.adapter.array',
+                    'default_lifetime' => 410,
+                    'tags' => true,
+                ],
+                'cache.redis_tag_aware.foo' => [
+                    'adapter' => 'cache.adapter.redis_tag_aware',
+                ],
+                'cache.redis_tag_aware.foo2' => [
+                    'tags' => true,
+                    'adapter' => 'cache.adapter.redis_tag_aware',
+                ],
+                'cache.redis_tag_aware.bar' => [
+                    'adapter' => 'cache.redis_tag_aware.foo',
+                ],
+                'cache.redis_tag_aware.bar2' => [
+                    'tags' => true,
+                    'adapter' => 'cache.redis_tag_aware.foo',
+                ],
+                'cache.redis_tag_aware.baz' => [
+                    'adapter' => 'cache.redis_tag_aware.foo2',
+                ],
+                'cache.redis_tag_aware.baz2' => [
+                    'tags' => true,
+                    'adapter' => 'cache.redis_tag_aware.foo2',
                 ],
-            ],
-            'cache.ccc' => [
-                'adapter' => 'cache.adapter.array',
-                'default_lifetime' => 410,
-                'tags' => true,
-            ],
-            'cache.redis_tag_aware.foo' => [
-                'adapter' => 'cache.adapter.redis_tag_aware',
-            ],
-            'cache.redis_tag_aware.foo2' => [
-                'tags' => true,
-                'adapter' => 'cache.adapter.redis_tag_aware',
-            ],
-            'cache.redis_tag_aware.bar' => [
-                'adapter' => 'cache.redis_tag_aware.foo',
-            ],
-            'cache.redis_tag_aware.bar2' => [
-                'tags' => true,
-                'adapter' => 'cache.redis_tag_aware.foo',
-            ],
-            'cache.redis_tag_aware.baz' => [
-                'adapter' => 'cache.redis_tag_aware.foo2',
-            ],
-            'cache.redis_tag_aware.baz2' => [
-                'tags' => true,
-                'adapter' => 'cache.redis_tag_aware.foo2',
             ],
         ],
-    ],
-]);
+    ]);
+};
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/xml/cache.xml b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/xml/cache.xml
index b4625a26d2bda..b9074041daea5 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/xml/cache.xml
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/xml/cache.xml
@@ -5,6 +5,18 @@
     xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd
         http://symfony.com/schema/dic/symfony https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">
 
+    <services>
+        <defaults autowire="true" autoconfigure="true"/>
+
+        <service id="chain_cache_custom_ns" class="Symfony\Component\Cache\Adapter\ChainAdapter">
+            <argument type="collection">
+                <argument type="service" id="cache.adapter.array"/>
+                <argument type="service" id="cache.adapter.filesystem"/>
+            </argument>
+            <tag name="cache.pool" namespace="my-custom-ns" />
+        </service>
+    </services>
+
     <framework:config http-method-override="false" handle-all-throwables="true">
         <framework:annotations enabled="false" />
         <framework:php-errors log="true" />
@@ -19,6 +31,7 @@
                 <framework:adapter name="cache.adapter.filesystem" />
                 <framework:adapter name="cache.adapter.redis" provider="redis://foo" />
             </framework:pool>
+            <framework:pool name="cache.custom_ns_chain" adapter="chain_cache_custom_ns" default-lifetime="12" />
             <framework:pool name="cache.ccc" adapter="cache.adapter.array" default-lifetime="410" tags="true" />
             <framework:pool name="cache.redis_tag_aware.foo" adapter="cache.adapter.redis_tag_aware" />
             <framework:pool name="cache.redis_tag_aware.foo2" tags="true" adapter="cache.adapter.redis_tag_aware" />
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/yml/cache.yml b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/yml/cache.yml
index e88c77f1c38b7..667279b2121d8 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/yml/cache.yml
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/yml/cache.yml
@@ -1,3 +1,16 @@
+services:
+    _defaults:
+        autowire: true
+        autoconfigure: true
+
+    chain_cache_custom_ns:
+        class: Symfony\Component\Cache\Adapter\ChainAdapter
+        arguments:
+            - ['@cache.adapter.array', '@cache.adapter.filesystem']
+        tags:
+            - { name: cache.pool, namespace: 'my-custom-ns' }
+
+
 framework:
     annotations: false
     http_method_override: false
@@ -26,6 +39,9 @@ framework:
                     - cache.adapter.array
                     - cache.adapter.filesystem
                     - {name: cache.adapter.redis, provider: 'redis://foo'}
+            cache.custom_ns_chain:
+                default_lifetime: 12
+                adapter: 'chain_cache_custom_ns'
             cache.ccc:
                 adapter: cache.adapter.array
                 default_lifetime: 410
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTestCase.php b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTestCase.php
index 7f94b83ce58c4..15f912f71c306 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTestCase.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTestCase.php
@@ -1752,6 +1752,7 @@ public function testCachePoolServices()
     {
         $container = $this->createContainerFromFile('cache', [], true, false);
         $container->setParameter('cache.prefix.seed', 'test');
+        $container->addCompilerPass(new ResolveInstanceofConditionalsPass());
         $container->addCompilerPass(new CachePoolPass());
         $container->compile();
 
@@ -1762,9 +1763,7 @@ public function testCachePoolServices()
         $this->assertCachePoolServiceDefinitionIsCreated($container, 'cache.expr', 'cache.app', '13 seconds');
 
         $chain = $container->getDefinition('cache.chain');
-
         $this->assertSame(ChainAdapter::class, $chain->getClass());
-
         $this->assertCount(2, $chain->getArguments());
         $this->assertCount(3, $chain->getArguments()[0]);
 
@@ -1785,6 +1784,22 @@ public function testCachePoolServices()
         ];
         $this->assertEquals($expected, $chain->getArguments());
 
+        $chainCustomNs = $container->getDefinition('cache.custom_ns_chain');
+        $this->assertCount(2, $chainCustomNs->getArguments());
+        $this->assertCount(2, $chainCustomNs->getArguments()['index_0']);
+
+        $expectedCustomNsChain = [
+            'index_0' => [
+                (new ChildDefinition('cache.adapter.array'))
+                    ->replaceArgument(0, 12),
+                (new ChildDefinition('cache.adapter.filesystem'))
+                    ->replaceArgument(0, 'my-custom-ns')
+                    ->replaceArgument(1, 12),
+            ],
+            'index_1' => 12,
+        ];
+        $this->assertEquals($expectedCustomNsChain, $chainCustomNs->getArguments());
+
         // Test "tags: true" wrapping logic
         $tagAwareDefinition = $container->getDefinition('cache.ccc');
         $this->assertSame(TagAwareAdapter::class, $tagAwareDefinition->getClass());
diff --git a/src/Symfony/Component/Cache/DependencyInjection/CachePoolPass.php b/src/Symfony/Component/Cache/DependencyInjection/CachePoolPass.php
index 90c089074ef4b..4c3f6fe1bc98f 100644
--- a/src/Symfony/Component/Cache/DependencyInjection/CachePoolPass.php
+++ b/src/Symfony/Component/Cache/DependencyInjection/CachePoolPass.php
@@ -58,7 +58,7 @@ public function process(ContainerBuilder $container)
                 continue;
             }
             $class = $adapter->getClass();
-            while ($adapter instanceof ChildDefinition) {
+            while (ChainAdapter::class !== $class && $adapter instanceof ChildDefinition) {
                 $adapter = $container->findDefinition($adapter->getParent());
                 $class = $class ?: $adapter->getClass();
                 if ($t = $adapter->getTag('cache.pool')) {