From 24d8740d71a2cac18a32834725e10f584283eeae Mon Sep 17 00:00:00 2001
From: Till Hildebrandt <th@facelift-bbt.com>
Date: Thu, 21 Nov 2019 13:51:43 +0100
Subject: [PATCH 01/11] Added cache_listeners to Configuration and Extension

---
 src/DependencyInjection/Configuration.php    | 7 +++++++
 src/DependencyInjection/HttplugExtension.php | 7 +++++++
 2 files changed, 14 insertions(+)

diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index f2982d35..6836f54a 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -3,6 +3,7 @@
 namespace Http\HttplugBundle\DependencyInjection;
 
 use Http\Client\Common\Plugin\Cache\Generator\CacheKeyGenerator;
+use Http\Client\Common\Plugin\Cache\Listener\CacheListener;
 use Http\Client\Common\Plugin\CachePlugin;
 use Http\Client\Common\Plugin\Journal;
 use Http\Client\Plugin\Vcr\NamingStrategy\NamingStrategyInterface;
@@ -739,6 +740,12 @@ private function createCachePluginNode()
                         ->end()
                     ->end()
                 ->end()
+                ->arrayNode('cache_listeners')
+                    ->info('An array of services to act on the response based on the results of the cache check. Must implement ' . CacheListener::class . ' Defaults to an empty array.')
+                    ->defaultValue([])
+                    ->prototype('scalar')
+                    ->end()
+                ->end()
                 ->scalarNode('respect_cache_headers')
                     ->info('Whether we should care about cache headers or not [DEPRECATED]')
                     ->beforeNormalization()
diff --git a/src/DependencyInjection/HttplugExtension.php b/src/DependencyInjection/HttplugExtension.php
index 61a734b5..21387d2d 100644
--- a/src/DependencyInjection/HttplugExtension.php
+++ b/src/DependencyInjection/HttplugExtension.php
@@ -203,10 +203,17 @@ private function configurePluginByName($name, Definition $definition, array $con
         switch ($name) {
             case 'cache':
                 $options = $config['config'];
+
                 if (!empty($options['cache_key_generator'])) {
                     $options['cache_key_generator'] = new Reference($options['cache_key_generator']);
                 }
 
+                if (!empty($options['cache_listeners'])) {
+                    foreach ($options['cache_listeners'] as $i => $listener) {
+                        $options['cache_listeners'][$i] = new Reference($listener);
+                    }
+                }
+
                 $definition
                     ->replaceArgument(0, new Reference($config['cache_pool']))
                     ->replaceArgument(1, new Reference($config['stream_factory']))

From 6eab39f4a88b508f2337eb2fbf684363c042b261 Mon Sep 17 00:00:00 2001
From: Till Hildebrandt <th@facelift-bbt.com>
Date: Wed, 27 Nov 2019 11:36:22 +0100
Subject: [PATCH 02/11] Wrapped php-http/cache-plugin Cache Listeners  - fixed
 tests, extended by cache_listeners

---
 tests/Resources/Fixtures/config/full.php             | 1 +
 tests/Resources/Fixtures/config/full.xml             | 2 +-
 tests/Resources/Fixtures/config/full.yml             | 1 +
 tests/Unit/DependencyInjection/ConfigurationTest.php | 4 ++++
 4 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/tests/Resources/Fixtures/config/full.php b/tests/Resources/Fixtures/config/full.php
index 8c9def8a..60a5a6b9 100644
--- a/tests/Resources/Fixtures/config/full.php
+++ b/tests/Resources/Fixtures/config/full.php
@@ -102,6 +102,7 @@
                 'methods' => ['GET'],
                 'cache_key_generator' => null,
                 'respect_response_cache_directives' => ['X-Foo'],
+                'cache_listeners' => null,
             ],
         ],
         'cookie' => [
diff --git a/tests/Resources/Fixtures/config/full.xml b/tests/Resources/Fixtures/config/full.xml
index 607438de..de9d298b 100644
--- a/tests/Resources/Fixtures/config/full.xml
+++ b/tests/Resources/Fixtures/config/full.xml
@@ -54,7 +54,7 @@
                 <my_service type="service" service="my_auth_service"/>
             </authentication>
             <cache cache-pool="my_cache_pool" stream-factory="my_other_stream_factory">
-                <config default-ttl="42" cache-lifetime="2592000" hash-algo="sha1" cache-key-generator="null">
+                <config default-ttl="42" cache-lifetime="2592000" hash-algo="sha1" cache-key-generator="null" cache-listeners="null">
                     <respect-response-cache-directive>X-Foo</respect-response-cache-directive>
                     <method>GET</method>
                 </config>
diff --git a/tests/Resources/Fixtures/config/full.yml b/tests/Resources/Fixtures/config/full.yml
index 03c97d9a..eecb6dd6 100644
--- a/tests/Resources/Fixtures/config/full.yml
+++ b/tests/Resources/Fixtures/config/full.yml
@@ -73,6 +73,7 @@ httplug:
                 cache_key_generator: null
                 respect_response_cache_directives:
                   - X-Foo
+                cache_listeners: null
         cookie:
             cookie_jar: my_cookie_jar
         decoder:
diff --git a/tests/Unit/DependencyInjection/ConfigurationTest.php b/tests/Unit/DependencyInjection/ConfigurationTest.php
index a9fd4ba4..62bf5fb2 100644
--- a/tests/Unit/DependencyInjection/ConfigurationTest.php
+++ b/tests/Unit/DependencyInjection/ConfigurationTest.php
@@ -43,6 +43,7 @@ class ConfigurationTest extends AbstractExtensionConfigurationTestCase
                 'stream_factory' => 'httplug.stream_factory',
                 'config' => [
                     'methods' => ['GET', 'HEAD'],
+                    'cache_listeners' => []
                 ],
             ],
             'cookie' => [
@@ -233,6 +234,7 @@ public function testSupportsAllConfigFormats(): void
                         'methods' => ['GET'],
                         'cache_key_generator' => null,
                         'respect_response_cache_directives' => ['X-Foo'],
+                        'cache_listeners' => [],
                     ],
                 ],
                 'cookie' => [
@@ -354,6 +356,7 @@ public function testCacheConfigDeprecationCompatibility(): void
             'config' => [
                 'methods' => ['GET', 'HEAD'],
                 'respect_cache_headers' => true,
+                'cache_listeners' => [],
             ],
         ]);
         $this->assertProcessedConfigurationEquals($config, [$file]);
@@ -372,6 +375,7 @@ public function testCacheConfigDeprecationCompatibilityIssue166(): void
             'config' => [
                 'methods' => ['GET', 'HEAD'],
                 'respect_cache_headers' => false,
+                'cache_listeners' => [],
             ],
         ]);
         $this->assertProcessedConfigurationEquals($config, [$file]);

From 440f4949c3f803c67f4ee8fc7a2c8142081672bb Mon Sep 17 00:00:00 2001
From: Till Hildebrandt <th@facelift-bbt.com>
Date: Thu, 28 Nov 2019 08:29:04 +0100
Subject: [PATCH 03/11] Wrapped php-http/cache-plugin cache_listeners  - list
 of classes to match plugins documentation  - added to config  - added tests

---
 src/DependencyInjection/Configuration.php     | 18 +++++++-
 src/DependencyInjection/HttplugExtension.php  |  7 +++-
 tests/Resources/Fixtures/config/full.php      |  2 +-
 tests/Resources/Fixtures/config/full.xml      |  2 +-
 tests/Resources/Fixtures/config/full.yml      |  2 +-
 .../config/invalid_cache_listener_config.yml  |  6 +++
 .../DependencyInjection/ConfigurationTest.php | 11 +++++
 .../HttplugExtensionTest.php                  | 42 +++++++++++++++++++
 8 files changed, 85 insertions(+), 5 deletions(-)
 create mode 100644 tests/Resources/Fixtures/config/invalid_cache_listener_config.yml

diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index 6836f54a..e95f428d 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -14,6 +14,7 @@
 use Http\Message\StreamFactory;
 use Psr\Cache\CacheItemPoolInterface;
 use Psr\Log\LoggerInterface;
+use ReflectionClass;
 use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
 use Symfony\Component\Config\Definition\Builder\NodeDefinition;
 use Symfony\Component\Config\Definition\Builder\TreeBuilder;
@@ -741,9 +742,24 @@ private function createCachePluginNode()
                     ->end()
                 ->end()
                 ->arrayNode('cache_listeners')
-                    ->info('An array of services to act on the response based on the results of the cache check. Must implement ' . CacheListener::class . ' Defaults to an empty array.')
+                    ->info('An array of classes to act on the response based on the results of the cache check. Must implement ' . CacheListener::class . '. Defaults to an empty array.')
+                    ->beforeNormalization()->castToArray()->ifEmpty()->thenUnset()->end()
                     ->defaultValue([])
                     ->prototype('scalar')
+                        ->validate()
+                            ->ifTrue(function ($v) {
+                                $vs = is_array($v) ? $v : (is_null($v) ? [] : [$v]);
+
+                                return empty($vs) || array_reduce($vs, function($r, $e) {
+                                    return empty($e) || !class_exists($e) || !(new ReflectionClass($e))->implementsInterface(CacheListener::class);
+                                }, false);
+                            })
+                            ->thenInvalid('A given listener class does not implement '.CacheListener::class)
+                        ->end()
+                    ->end()
+                    ->validate()
+                        ->ifEmpty()
+                        ->thenUnset()
                     ->end()
                 ->end()
                 ->scalarNode('respect_cache_headers')
diff --git a/src/DependencyInjection/HttplugExtension.php b/src/DependencyInjection/HttplugExtension.php
index 21387d2d..08697cd7 100644
--- a/src/DependencyInjection/HttplugExtension.php
+++ b/src/DependencyInjection/HttplugExtension.php
@@ -210,9 +210,14 @@ private function configurePluginByName($name, Definition $definition, array $con
 
                 if (!empty($options['cache_listeners'])) {
                     foreach ($options['cache_listeners'] as $i => $listener) {
-                        $options['cache_listeners'][$i] = new Reference($listener);
+                        if (!empty($listener)) {
+                            $options['cache_listeners'][$i] = new Definition($listener);
+                        }
                     }
                 }
+                if (! count($options['cache_listeners'])) {
+                    unset($options['cache_listeners']);
+                }
 
                 $definition
                     ->replaceArgument(0, new Reference($config['cache_pool']))
diff --git a/tests/Resources/Fixtures/config/full.php b/tests/Resources/Fixtures/config/full.php
index 60a5a6b9..d087a24e 100644
--- a/tests/Resources/Fixtures/config/full.php
+++ b/tests/Resources/Fixtures/config/full.php
@@ -102,7 +102,7 @@
                 'methods' => ['GET'],
                 'cache_key_generator' => null,
                 'respect_response_cache_directives' => ['X-Foo'],
-                'cache_listeners' => null,
+                'cache_listeners' => [],
             ],
         ],
         'cookie' => [
diff --git a/tests/Resources/Fixtures/config/full.xml b/tests/Resources/Fixtures/config/full.xml
index de9d298b..f08f436c 100644
--- a/tests/Resources/Fixtures/config/full.xml
+++ b/tests/Resources/Fixtures/config/full.xml
@@ -54,7 +54,7 @@
                 <my_service type="service" service="my_auth_service"/>
             </authentication>
             <cache cache-pool="my_cache_pool" stream-factory="my_other_stream_factory">
-                <config default-ttl="42" cache-lifetime="2592000" hash-algo="sha1" cache-key-generator="null" cache-listeners="null">
+                <config default-ttl="42" cache-lifetime="2592000" hash-algo="sha1" cache-key-generator="null" cache-listeners="">
                     <respect-response-cache-directive>X-Foo</respect-response-cache-directive>
                     <method>GET</method>
                 </config>
diff --git a/tests/Resources/Fixtures/config/full.yml b/tests/Resources/Fixtures/config/full.yml
index eecb6dd6..13165464 100644
--- a/tests/Resources/Fixtures/config/full.yml
+++ b/tests/Resources/Fixtures/config/full.yml
@@ -73,7 +73,7 @@ httplug:
                 cache_key_generator: null
                 respect_response_cache_directives:
                   - X-Foo
-                cache_listeners: null
+                cache_listeners: []
         cookie:
             cookie_jar: my_cookie_jar
         decoder:
diff --git a/tests/Resources/Fixtures/config/invalid_cache_listener_config.yml b/tests/Resources/Fixtures/config/invalid_cache_listener_config.yml
new file mode 100644
index 00000000..3cfab6c2
--- /dev/null
+++ b/tests/Resources/Fixtures/config/invalid_cache_listener_config.yml
@@ -0,0 +1,6 @@
+httplug:
+    plugins:
+        cache:
+            cache_pool: my_cache_pool
+            config:
+                cache_listeners: ['NotExistentClass']
diff --git a/tests/Unit/DependencyInjection/ConfigurationTest.php b/tests/Unit/DependencyInjection/ConfigurationTest.php
index 62bf5fb2..a5d6c884 100644
--- a/tests/Unit/DependencyInjection/ConfigurationTest.php
+++ b/tests/Unit/DependencyInjection/ConfigurationTest.php
@@ -2,6 +2,7 @@
 
 namespace Http\HttplugBundle\Tests\Unit\DependencyInjection;
 
+use Http\Client\Common\Plugin\Cache\Listener\CacheListener;
 use Http\HttplugBundle\DependencyInjection\Configuration;
 use Http\HttplugBundle\DependencyInjection\HttplugExtension;
 use Matthias\SymfonyDependencyInjectionTest\PhpUnit\AbstractExtensionConfigurationTestCase;
@@ -424,4 +425,14 @@ public function testInvalidCapturedBodyLengthString(): void
         $this->expectExceptionMessage('The child node "captured_body_length" at path "httplug.profiling" must be an integer or null');
         $this->assertProcessedConfigurationEquals([], [$file]);
     }
+
+    public function testInvalidCacheConfigCacheListeners(): void
+    {
+        $file = __DIR__.'/../../Resources/Fixtures/config/invalid_cache_listener_config.yml';
+
+        $this->expectException(InvalidConfigurationException::class);
+        $this->expectExceptionMessage('A given listener class does not implement '.CacheListener::class);
+
+        $this->assertProcessedConfigurationEquals($this->emptyConfig, [$file]);
+    }
 }
diff --git a/tests/Unit/DependencyInjection/HttplugExtensionTest.php b/tests/Unit/DependencyInjection/HttplugExtensionTest.php
index 54f6cc75..a5869a0d 100644
--- a/tests/Unit/DependencyInjection/HttplugExtensionTest.php
+++ b/tests/Unit/DependencyInjection/HttplugExtensionTest.php
@@ -7,6 +7,7 @@
 use Http\HttplugBundle\Collector\PluginClientFactoryListener;
 use Http\HttplugBundle\DependencyInjection\HttplugExtension;
 use Matthias\SymfonyDependencyInjectionTest\PhpUnit\AbstractExtensionTestCase;
+use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Reference;
 use Symfony\Component\HttpKernel\Kernel;
 use Http\Adapter\Guzzle6\Client;
@@ -261,6 +262,47 @@ public function testCachePluginConfigCacheKeyGeneratorReference(): void
         $this->assertSame('header_cache_key_generator', (string) $config['cache_key_generator']);
     }
 
+    public function testCachePluginConfigCacheListenersDefinition(): void
+    {
+        $this->load([
+            'plugins' => [
+                'cache' => [
+                    'cache_pool' => 'my_cache_pool',
+                    'config' => [
+                        'cache_listeners' => [
+                            '\Http\Client\Common\Plugin\Cache\Listener\AddHeaderCacheListener'
+                        ],
+                    ],
+                ],
+            ],
+        ]);
+
+        $cachePlugin = $this->container->findDefinition('httplug.plugin.cache');
+
+        $config = $cachePlugin->getArgument(2);
+        $this->assertArrayHasKey('cache_listeners', $config);
+        $this->assertContainsOnlyInstancesOf(Definition::class, $config['cache_listeners']);
+    }
+
+    public function testCachePluginInvalidConfigCacheListenersDefinition(): void
+    {
+        $this->load([
+            'plugins' => [
+                'cache' => [
+                    'cache_pool' => 'my_cache_pool',
+                    'config' => [
+                        'cache_listeners' => [],
+                    ],
+                ],
+            ],
+        ]);
+
+        $cachePlugin = $this->container->findDefinition('httplug.plugin.cache');
+
+        $config = $cachePlugin->getArgument(2);
+        $this->assertArrayNotHasKey('cache_listeners', $config);
+    }
+
     public function testContentTypePluginAllowedOptions(): void
     {
         $this->load([

From 1bfe50482e154dffb0048ec4fdd41077ac333fba Mon Sep 17 00:00:00 2001
From: Till Hildebrandt <th@facelift-bbt.com>
Date: Thu, 28 Nov 2019 08:34:59 +0100
Subject: [PATCH 04/11] Wrapped php-http/cache-plugin Cache Listeners  -
 updated changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b72402ff..07b4daed 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ The change log describes what is "Added", "Removed", "Changed" or "Fixed" betwee
 - Configured clients are now tagged with `'httplug.client'`
 - Adds a link to profiler page when response is from a Symfony application with
   profiler enabled
+- Adding `cache_listeners` option of `php-http/cache-plugin`
 
 ### Changed
 

From 9acd7b6e56a95b1469842346ad9455d21cb4e593 Mon Sep 17 00:00:00 2001
From: Till Hildebrandt <th@facelift-bbt.com>
Date: Thu, 28 Nov 2019 08:46:25 +0100
Subject: [PATCH 05/11] Fixing CI

---
 src/DependencyInjection/Configuration.php               | 4 ++--
 src/DependencyInjection/HttplugExtension.php            | 2 +-
 tests/Unit/DependencyInjection/ConfigurationTest.php    | 2 +-
 tests/Unit/DependencyInjection/HttplugExtensionTest.php | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index e95f428d..9166eff8 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -742,7 +742,7 @@ private function createCachePluginNode()
                     ->end()
                 ->end()
                 ->arrayNode('cache_listeners')
-                    ->info('An array of classes to act on the response based on the results of the cache check. Must implement ' . CacheListener::class . '. Defaults to an empty array.')
+                    ->info('An array of classes to act on the response based on the results of the cache check. Must implement '.CacheListener::class.'. Defaults to an empty array.')
                     ->beforeNormalization()->castToArray()->ifEmpty()->thenUnset()->end()
                     ->defaultValue([])
                     ->prototype('scalar')
@@ -750,7 +750,7 @@ private function createCachePluginNode()
                             ->ifTrue(function ($v) {
                                 $vs = is_array($v) ? $v : (is_null($v) ? [] : [$v]);
 
-                                return empty($vs) || array_reduce($vs, function($r, $e) {
+                                return empty($vs) || array_reduce($vs, function ($r, $e) {
                                     return empty($e) || !class_exists($e) || !(new ReflectionClass($e))->implementsInterface(CacheListener::class);
                                 }, false);
                             })
diff --git a/src/DependencyInjection/HttplugExtension.php b/src/DependencyInjection/HttplugExtension.php
index 08697cd7..d95c49c9 100644
--- a/src/DependencyInjection/HttplugExtension.php
+++ b/src/DependencyInjection/HttplugExtension.php
@@ -215,7 +215,7 @@ private function configurePluginByName($name, Definition $definition, array $con
                         }
                     }
                 }
-                if (! count($options['cache_listeners'])) {
+                if (!count($options['cache_listeners'])) {
                     unset($options['cache_listeners']);
                 }
 
diff --git a/tests/Unit/DependencyInjection/ConfigurationTest.php b/tests/Unit/DependencyInjection/ConfigurationTest.php
index a5d6c884..618eba9d 100644
--- a/tests/Unit/DependencyInjection/ConfigurationTest.php
+++ b/tests/Unit/DependencyInjection/ConfigurationTest.php
@@ -44,7 +44,7 @@ class ConfigurationTest extends AbstractExtensionConfigurationTestCase
                 'stream_factory' => 'httplug.stream_factory',
                 'config' => [
                     'methods' => ['GET', 'HEAD'],
-                    'cache_listeners' => []
+                    'cache_listeners' => [],
                 ],
             ],
             'cookie' => [
diff --git a/tests/Unit/DependencyInjection/HttplugExtensionTest.php b/tests/Unit/DependencyInjection/HttplugExtensionTest.php
index a5869a0d..6e70eb43 100644
--- a/tests/Unit/DependencyInjection/HttplugExtensionTest.php
+++ b/tests/Unit/DependencyInjection/HttplugExtensionTest.php
@@ -270,7 +270,7 @@ public function testCachePluginConfigCacheListenersDefinition(): void
                     'cache_pool' => 'my_cache_pool',
                     'config' => [
                         'cache_listeners' => [
-                            '\Http\Client\Common\Plugin\Cache\Listener\AddHeaderCacheListener'
+                            '\Http\Client\Common\Plugin\Cache\Listener\AddHeaderCacheListener',
                         ],
                     ],
                 ],

From 194e8a5ad967a78fc048d69944cb2973adf93f61 Mon Sep 17 00:00:00 2001
From: Till Hildebrandt <th@facelift-bbt.com>
Date: Mon, 16 Dec 2019 09:29:17 +0100
Subject: [PATCH 06/11] Pull-Request Feedback for "Wrapped
 php-http/cache-plugin Cache Listeners"  - switched from list of classes to
 list of services  - removed class implementation validation in configuration

---
 src/DependencyInjection/Configuration.php     | 21 ++--------
 src/DependencyInjection/HttplugExtension.php  |  2 +-
 .../config/invalid_cache_listener_config.yml  |  6 ---
 .../DependencyInjection/ConfigurationTest.php | 39 +++++++------------
 .../HttplugExtensionTest.php                  | 25 ++----------
 5 files changed, 22 insertions(+), 71 deletions(-)
 delete mode 100644 tests/Resources/Fixtures/config/invalid_cache_listener_config.yml

diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index 9166eff8..686b0143 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -21,6 +21,8 @@
 use Symfony\Component\Config\Definition\ConfigurationInterface;
 use Symfony\Component\Config\Definition\Exception\InvalidConfigurationException;
 use Symfony\Component\Config\Definition\Exception\InvalidTypeException;
+use Symfony\Component\DependencyInjection\Definition;
+use Symfony\Component\DependencyInjection\Reference;
 
 /**
  * This class contains the configuration information for the bundle.
@@ -742,24 +744,9 @@ private function createCachePluginNode()
                     ->end()
                 ->end()
                 ->arrayNode('cache_listeners')
-                    ->info('An array of classes to act on the response based on the results of the cache check. Must implement '.CacheListener::class.'. Defaults to an empty array.')
-                    ->beforeNormalization()->castToArray()->ifEmpty()->thenUnset()->end()
-                    ->defaultValue([])
+                    ->info('A list of service ids to act on the response based on the results of the cache check. Must implement '.CacheListener::class.'. Defaults to an empty array.')
+                    ->beforeNormalization()->ifNull()->thenEmptyArray()->castToArray()->ifEmpty()->thenUnset()->end()
                     ->prototype('scalar')
-                        ->validate()
-                            ->ifTrue(function ($v) {
-                                $vs = is_array($v) ? $v : (is_null($v) ? [] : [$v]);
-
-                                return empty($vs) || array_reduce($vs, function ($r, $e) {
-                                    return empty($e) || !class_exists($e) || !(new ReflectionClass($e))->implementsInterface(CacheListener::class);
-                                }, false);
-                            })
-                            ->thenInvalid('A given listener class does not implement '.CacheListener::class)
-                        ->end()
-                    ->end()
-                    ->validate()
-                        ->ifEmpty()
-                        ->thenUnset()
                     ->end()
                 ->end()
                 ->scalarNode('respect_cache_headers')
diff --git a/src/DependencyInjection/HttplugExtension.php b/src/DependencyInjection/HttplugExtension.php
index d95c49c9..e2bd8ba2 100644
--- a/src/DependencyInjection/HttplugExtension.php
+++ b/src/DependencyInjection/HttplugExtension.php
@@ -211,7 +211,7 @@ private function configurePluginByName($name, Definition $definition, array $con
                 if (!empty($options['cache_listeners'])) {
                     foreach ($options['cache_listeners'] as $i => $listener) {
                         if (!empty($listener)) {
-                            $options['cache_listeners'][$i] = new Definition($listener);
+                            $options['cache_listeners'][$i] = new Reference($listener);
                         }
                     }
                 }
diff --git a/tests/Resources/Fixtures/config/invalid_cache_listener_config.yml b/tests/Resources/Fixtures/config/invalid_cache_listener_config.yml
deleted file mode 100644
index 3cfab6c2..00000000
--- a/tests/Resources/Fixtures/config/invalid_cache_listener_config.yml
+++ /dev/null
@@ -1,6 +0,0 @@
-httplug:
-    plugins:
-        cache:
-            cache_pool: my_cache_pool
-            config:
-                cache_listeners: ['NotExistentClass']
diff --git a/tests/Unit/DependencyInjection/ConfigurationTest.php b/tests/Unit/DependencyInjection/ConfigurationTest.php
index 1f010ed2..6002b225 100644
--- a/tests/Unit/DependencyInjection/ConfigurationTest.php
+++ b/tests/Unit/DependencyInjection/ConfigurationTest.php
@@ -2,7 +2,6 @@
 
 namespace Http\HttplugBundle\Tests\Unit\DependencyInjection;
 
-use Http\Client\Common\Plugin\Cache\Listener\CacheListener;
 use Http\HttplugBundle\DependencyInjection\Configuration;
 use Http\HttplugBundle\DependencyInjection\HttplugExtension;
 use Matthias\SymfonyDependencyInjectionTest\PhpUnit\AbstractExtensionConfigurationTestCase;
@@ -97,7 +96,7 @@ protected function getConfiguration(): ConfigurationInterface
     public function testEmptyConfiguration(): void
     {
         $formats = array_map(function ($path) {
-            return __DIR__.'/../../Resources/Fixtures/'.$path;
+            return __DIR__ . '/../../Resources/Fixtures/' . $path;
         }, [
             'config/empty.yml',
             'config/empty.xml',
@@ -278,7 +277,7 @@ public function testSupportsAllConfigFormats(): void
         ];
 
         $formats = array_map(function ($path) {
-            return __DIR__.'/../../Resources/Fixtures/'.$path;
+            return __DIR__ . '/../../Resources/Fixtures/' . $path;
         }, [
             'config/full.yml',
             'config/full.xml',
@@ -292,7 +291,7 @@ public function testSupportsAllConfigFormats(): void
 
     public function testMissingClass(): void
     {
-        $file = __DIR__.'/../../Resources/Fixtures/config/invalid_class.yml';
+        $file = __DIR__ . '/../../Resources/Fixtures/config/invalid_class.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('Nonexisting\Class');
@@ -301,7 +300,7 @@ public function testMissingClass(): void
 
     public function testInvalidPlugin(): void
     {
-        $file = __DIR__.'/../../Resources/Fixtures/config/invalid_plugin.yml';
+        $file = __DIR__ . '/../../Resources/Fixtures/config/invalid_plugin.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('Unrecognized option "foobar" under "httplug.clients.acme.plugins.0"');
@@ -310,7 +309,7 @@ public function testInvalidPlugin(): void
 
     public function testInvalidAuthentication(): void
     {
-        $file = __DIR__.'/../../Resources/Fixtures/config/invalid_auth.yml';
+        $file = __DIR__ . '/../../Resources/Fixtures/config/invalid_auth.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('password, service, username');
@@ -322,7 +321,7 @@ public function testInvalidAuthentication(): void
      */
     public function testInvalidCacheConfig(): void
     {
-        $file = __DIR__.'/../../Resources/Fixtures/config/invalid_cache_config.yml';
+        $file = __DIR__ . '/../../Resources/Fixtures/config/invalid_cache_config.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('Invalid configuration for path "httplug.plugins.cache.config": You can\'t provide config option "respect_cache_headers" and "respect_response_cache_directives" simultaniously. Use "respect_response_cache_directives" instead.');
@@ -335,7 +334,7 @@ public function testInvalidCacheConfig(): void
     public function testBackwardCompatibility(): void
     {
         $formats = array_map(function ($path) {
-            return __DIR__.'/../../Resources/Fixtures/'.$path;
+            return __DIR__ . '/../../Resources/Fixtures/' . $path;
         }, [
             'config/bc/toolbar.yml',
             'config/bc/toolbar_auto.yml',
@@ -351,7 +350,7 @@ public function testBackwardCompatibility(): void
      */
     public function testCacheConfigDeprecationCompatibility(): void
     {
-        $file = __DIR__.'/../../Resources/Fixtures/config/bc/cache_config.yml';
+        $file = __DIR__ . '/../../Resources/Fixtures/config/bc/cache_config.yml';
         $config = $this->emptyConfig;
         $config['plugins']['cache'] = array_merge($config['plugins']['cache'], [
             'enabled' => true,
@@ -370,7 +369,7 @@ public function testCacheConfigDeprecationCompatibility(): void
      */
     public function testCacheConfigDeprecationCompatibilityIssue166(): void
     {
-        $file = __DIR__.'/../../Resources/Fixtures/config/bc/issue-166.yml';
+        $file = __DIR__ . '/../../Resources/Fixtures/config/bc/issue-166.yml';
         $config = $this->emptyConfig;
         $config['plugins']['cache'] = array_merge($config['plugins']['cache'], [
             'enabled' => true,
@@ -386,7 +385,7 @@ public function testCacheConfigDeprecationCompatibilityIssue166(): void
 
     public function testProfilingToolbarCollision(): void
     {
-        $file = __DIR__.'/../../Resources/Fixtures/config/bc/profiling_toolbar.yml';
+        $file = __DIR__ . '/../../Resources/Fixtures/config/bc/profiling_toolbar.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('Can\'t configure both "toolbar" and "profiling" section. The "toolbar" config is deprecated as of version 1.3.0, please only use "profiling".');
@@ -395,7 +394,7 @@ public function testProfilingToolbarCollision(): void
 
     public function testClientCacheConfigMustHavePool(): void
     {
-        $file = __DIR__.'/../../Resources/Fixtures/config/client_cache_config_with_no_pool.yml';
+        $file = __DIR__ . '/../../Resources/Fixtures/config/client_cache_config_with_no_pool.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('The child node "cache_pool" at path "httplug.clients.test.plugins.0.cache" must be configured.');
@@ -404,7 +403,7 @@ public function testClientCacheConfigMustHavePool(): void
 
     public function testCacheConfigMustHavePool(): void
     {
-        $file = __DIR__.'/../../Resources/Fixtures/config/cache_config_with_no_pool.yml';
+        $file = __DIR__ . '/../../Resources/Fixtures/config/cache_config_with_no_pool.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('The child node "cache_pool" at path "httplug.plugins.cache" must be configured.');
@@ -413,7 +412,7 @@ public function testCacheConfigMustHavePool(): void
 
     public function testLimitlessCapturedBodyLength(): void
     {
-        $file = __DIR__.'/../../Resources/Fixtures/config/limitless_captured_body_length.yml';
+        $file = __DIR__ . '/../../Resources/Fixtures/config/limitless_captured_body_length.yml';
         $config = $this->emptyConfig;
         $config['profiling']['captured_body_length'] = null;
         $this->assertProcessedConfigurationEquals($config, [$file]);
@@ -421,20 +420,10 @@ public function testLimitlessCapturedBodyLength(): void
 
     public function testInvalidCapturedBodyLengthString(): void
     {
-        $file = __DIR__.'/../../Resources/Fixtures/config/invalid_captured_body_length.yml';
+        $file = __DIR__ . '/../../Resources/Fixtures/config/invalid_captured_body_length.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('The child node "captured_body_length" at path "httplug.profiling" must be an integer or null');
         $this->assertProcessedConfigurationEquals([], [$file]);
     }
-
-    public function testInvalidCacheConfigCacheListeners(): void
-    {
-        $file = __DIR__.'/../../Resources/Fixtures/config/invalid_cache_listener_config.yml';
-
-        $this->expectException(InvalidConfigurationException::class);
-        $this->expectExceptionMessage('A given listener class does not implement '.CacheListener::class);
-
-        $this->assertProcessedConfigurationEquals($this->emptyConfig, [$file]);
-    }
 }
diff --git a/tests/Unit/DependencyInjection/HttplugExtensionTest.php b/tests/Unit/DependencyInjection/HttplugExtensionTest.php
index 41013071..f7248992 100644
--- a/tests/Unit/DependencyInjection/HttplugExtensionTest.php
+++ b/tests/Unit/DependencyInjection/HttplugExtensionTest.php
@@ -7,7 +7,6 @@
 use Http\HttplugBundle\Collector\PluginClientFactoryListener;
 use Http\HttplugBundle\DependencyInjection\HttplugExtension;
 use Matthias\SymfonyDependencyInjectionTest\PhpUnit\AbstractExtensionTestCase;
-use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Reference;
 use Symfony\Component\HttpKernel\Kernel;
 use Http\Adapter\Guzzle6\Client;
@@ -270,7 +269,7 @@ public function testCachePluginConfigCacheListenersDefinition(): void
                     'cache_pool' => 'my_cache_pool',
                     'config' => [
                         'cache_listeners' => [
-                            '\Http\Client\Common\Plugin\Cache\Listener\AddHeaderCacheListener',
+                            'httplug.plugin.cache.listeners.add_header',
                         ],
                     ],
                 ],
@@ -281,26 +280,8 @@ public function testCachePluginConfigCacheListenersDefinition(): void
 
         $config = $cachePlugin->getArgument(2);
         $this->assertArrayHasKey('cache_listeners', $config);
-        $this->assertContainsOnlyInstancesOf(Definition::class, $config['cache_listeners']);
-    }
-
-    public function testCachePluginInvalidConfigCacheListenersDefinition(): void
-    {
-        $this->load([
-            'plugins' => [
-                'cache' => [
-                    'cache_pool' => 'my_cache_pool',
-                    'config' => [
-                        'cache_listeners' => [],
-                    ],
-                ],
-            ],
-        ]);
-
-        $cachePlugin = $this->container->findDefinition('httplug.plugin.cache');
-
-        $config = $cachePlugin->getArgument(2);
-        $this->assertArrayNotHasKey('cache_listeners', $config);
+        $this->assertContainsOnlyInstancesOf(Reference::class, $config['cache_listeners']);
+        $this->assertSame('httplug.plugin.cache.listeners.add_header', (string) $config['cache_listeners'][0]);
     }
 
     public function testContentTypePluginAllowedOptions(): void

From 65a501441772ce42a16dee6a3c22f1c1436f1bad Mon Sep 17 00:00:00 2001
From: Till Hildebrandt <th@facelift-bbt.com>
Date: Mon, 16 Dec 2019 09:35:44 +0100
Subject: [PATCH 07/11] Pull-Request Feedback for "Wrapped
 php-http/cache-plugin Cache Listeners"  - Removed obsolete uses

---
 src/DependencyInjection/Configuration.php | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index 686b0143..07c95ef3 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -14,15 +14,12 @@
 use Http\Message\StreamFactory;
 use Psr\Cache\CacheItemPoolInterface;
 use Psr\Log\LoggerInterface;
-use ReflectionClass;
 use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
 use Symfony\Component\Config\Definition\Builder\NodeDefinition;
 use Symfony\Component\Config\Definition\Builder\TreeBuilder;
 use Symfony\Component\Config\Definition\ConfigurationInterface;
 use Symfony\Component\Config\Definition\Exception\InvalidConfigurationException;
 use Symfony\Component\Config\Definition\Exception\InvalidTypeException;
-use Symfony\Component\DependencyInjection\Definition;
-use Symfony\Component\DependencyInjection\Reference;
 
 /**
  * This class contains the configuration information for the bundle.

From 1fd748b258668b1e4f619568a58580e3ee62c655 Mon Sep 17 00:00:00 2001
From: Till Hildebrandt <th@facelift-bbt.com>
Date: Mon, 16 Dec 2019 09:39:44 +0100
Subject: [PATCH 08/11] Pull-Request Feedback for "Wrapped
 php-http/cache-plugin Cache Listeners"  - Reverted unwanted style changes
 (even though a additional space at    string concat is really nice ;))

---
 .../DependencyInjection/ConfigurationTest.php | 28 +++++++++----------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/tests/Unit/DependencyInjection/ConfigurationTest.php b/tests/Unit/DependencyInjection/ConfigurationTest.php
index 6002b225..c0829fa1 100644
--- a/tests/Unit/DependencyInjection/ConfigurationTest.php
+++ b/tests/Unit/DependencyInjection/ConfigurationTest.php
@@ -96,7 +96,7 @@ protected function getConfiguration(): ConfigurationInterface
     public function testEmptyConfiguration(): void
     {
         $formats = array_map(function ($path) {
-            return __DIR__ . '/../../Resources/Fixtures/' . $path;
+            return __DIR__.'/../../Resources/Fixtures/'.$path;
         }, [
             'config/empty.yml',
             'config/empty.xml',
@@ -277,7 +277,7 @@ public function testSupportsAllConfigFormats(): void
         ];
 
         $formats = array_map(function ($path) {
-            return __DIR__ . '/../../Resources/Fixtures/' . $path;
+            return __DIR__.'/../../Resources/Fixtures/'.$path;
         }, [
             'config/full.yml',
             'config/full.xml',
@@ -291,7 +291,7 @@ public function testSupportsAllConfigFormats(): void
 
     public function testMissingClass(): void
     {
-        $file = __DIR__ . '/../../Resources/Fixtures/config/invalid_class.yml';
+        $file = __DIR__.'/../../Resources/Fixtures/config/invalid_class.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('Nonexisting\Class');
@@ -300,7 +300,7 @@ public function testMissingClass(): void
 
     public function testInvalidPlugin(): void
     {
-        $file = __DIR__ . '/../../Resources/Fixtures/config/invalid_plugin.yml';
+        $file = __DIR__.'/../../Resources/Fixtures/config/invalid_plugin.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('Unrecognized option "foobar" under "httplug.clients.acme.plugins.0"');
@@ -309,7 +309,7 @@ public function testInvalidPlugin(): void
 
     public function testInvalidAuthentication(): void
     {
-        $file = __DIR__ . '/../../Resources/Fixtures/config/invalid_auth.yml';
+        $file = __DIR__.'/../../Resources/Fixtures/config/invalid_auth.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('password, service, username');
@@ -321,7 +321,7 @@ public function testInvalidAuthentication(): void
      */
     public function testInvalidCacheConfig(): void
     {
-        $file = __DIR__ . '/../../Resources/Fixtures/config/invalid_cache_config.yml';
+        $file = __DIR__.'/../../Resources/Fixtures/config/invalid_cache_config.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('Invalid configuration for path "httplug.plugins.cache.config": You can\'t provide config option "respect_cache_headers" and "respect_response_cache_directives" simultaniously. Use "respect_response_cache_directives" instead.');
@@ -334,7 +334,7 @@ public function testInvalidCacheConfig(): void
     public function testBackwardCompatibility(): void
     {
         $formats = array_map(function ($path) {
-            return __DIR__ . '/../../Resources/Fixtures/' . $path;
+            return __DIR__.'/../../Resources/Fixtures/'.$path;
         }, [
             'config/bc/toolbar.yml',
             'config/bc/toolbar_auto.yml',
@@ -350,7 +350,7 @@ public function testBackwardCompatibility(): void
      */
     public function testCacheConfigDeprecationCompatibility(): void
     {
-        $file = __DIR__ . '/../../Resources/Fixtures/config/bc/cache_config.yml';
+        $file = __DIR__.'/../../Resources/Fixtures/config/bc/cache_config.yml';
         $config = $this->emptyConfig;
         $config['plugins']['cache'] = array_merge($config['plugins']['cache'], [
             'enabled' => true,
@@ -369,7 +369,7 @@ public function testCacheConfigDeprecationCompatibility(): void
      */
     public function testCacheConfigDeprecationCompatibilityIssue166(): void
     {
-        $file = __DIR__ . '/../../Resources/Fixtures/config/bc/issue-166.yml';
+        $file = __DIR__.'/../../Resources/Fixtures/config/bc/issue-166.yml';
         $config = $this->emptyConfig;
         $config['plugins']['cache'] = array_merge($config['plugins']['cache'], [
             'enabled' => true,
@@ -385,7 +385,7 @@ public function testCacheConfigDeprecationCompatibilityIssue166(): void
 
     public function testProfilingToolbarCollision(): void
     {
-        $file = __DIR__ . '/../../Resources/Fixtures/config/bc/profiling_toolbar.yml';
+        $file = __DIR__.'/../../Resources/Fixtures/config/bc/profiling_toolbar.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('Can\'t configure both "toolbar" and "profiling" section. The "toolbar" config is deprecated as of version 1.3.0, please only use "profiling".');
@@ -394,7 +394,7 @@ public function testProfilingToolbarCollision(): void
 
     public function testClientCacheConfigMustHavePool(): void
     {
-        $file = __DIR__ . '/../../Resources/Fixtures/config/client_cache_config_with_no_pool.yml';
+        $file = __DIR__.'/../../Resources/Fixtures/config/client_cache_config_with_no_pool.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('The child node "cache_pool" at path "httplug.clients.test.plugins.0.cache" must be configured.');
@@ -403,7 +403,7 @@ public function testClientCacheConfigMustHavePool(): void
 
     public function testCacheConfigMustHavePool(): void
     {
-        $file = __DIR__ . '/../../Resources/Fixtures/config/cache_config_with_no_pool.yml';
+        $file = __DIR__.'/../../Resources/Fixtures/config/cache_config_with_no_pool.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('The child node "cache_pool" at path "httplug.plugins.cache" must be configured.');
@@ -412,7 +412,7 @@ public function testCacheConfigMustHavePool(): void
 
     public function testLimitlessCapturedBodyLength(): void
     {
-        $file = __DIR__ . '/../../Resources/Fixtures/config/limitless_captured_body_length.yml';
+        $file = __DIR__.'/../../Resources/Fixtures/config/limitless_captured_body_length.yml';
         $config = $this->emptyConfig;
         $config['profiling']['captured_body_length'] = null;
         $this->assertProcessedConfigurationEquals($config, [$file]);
@@ -420,7 +420,7 @@ public function testLimitlessCapturedBodyLength(): void
 
     public function testInvalidCapturedBodyLengthString(): void
     {
-        $file = __DIR__ . '/../../Resources/Fixtures/config/invalid_captured_body_length.yml';
+        $file = __DIR__.'/../../Resources/Fixtures/config/invalid_captured_body_length.yml';
 
         $this->expectException(InvalidConfigurationException::class);
         $this->expectExceptionMessage('The child node "captured_body_length" at path "httplug.profiling" must be an integer or null');

From bd0beb2c6903fa0f3fbda448bc15b4e78b7c5b69 Mon Sep 17 00:00:00 2001
From: Till Hildebrandt <th@facelift-bbt.com>
Date: Thu, 9 Jan 2020 12:20:47 +0100
Subject: [PATCH 09/11] Pull-Request-Feedback  - removed duplicated
 cache_listeners node from src/DependencyInjection/Configuration.php  - TESTS:
 added multiple cache_listeners

---
 src/DependencyInjection/Configuration.php            | 4 ----
 tests/Resources/Fixtures/config/full.php             | 5 ++++-
 tests/Resources/Fixtures/config/full.xml             | 3 ++-
 tests/Resources/Fixtures/config/full.yml             | 4 +++-
 tests/Unit/DependencyInjection/ConfigurationTest.php | 5 ++++-
 5 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index 800cc9e5..b7bc988c 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -751,10 +751,6 @@ private function createCachePluginNode()
                         ->end()
                     ->end()
                 ->end()
-                ->arrayNode('cache_listeners')
-                    ->info('A list of service ids to act on the response based on the results of the cache check. Must implement '.CacheListener::class.'. Defaults to an empty array.')
-                    ->beforeNormalization()->ifNull()->thenEmptyArray()->castToArray()->ifEmpty()->thenUnset()->end()
-                ->end()
                 ->enumNode('hash_algo')
                     ->info('Hashing algorithm to use')
                     ->values(hash_algos())
diff --git a/tests/Resources/Fixtures/config/full.php b/tests/Resources/Fixtures/config/full.php
index 3647d46c..14573391 100644
--- a/tests/Resources/Fixtures/config/full.php
+++ b/tests/Resources/Fixtures/config/full.php
@@ -110,7 +110,10 @@
                 'cache_key_generator' => null,
                 'respect_response_cache_directives' => ['X-Foo'],
                 'blacklisted_paths' => ['@/path/not-to-be/cached@'],
-                'cache_listeners' => [],
+                'cache_listeners' => [
+                    'my_cache_listener_0',
+                    'my_cache_listener_1',
+                ],
             ],
         ],
         'cookie' => [
diff --git a/tests/Resources/Fixtures/config/full.xml b/tests/Resources/Fixtures/config/full.xml
index bdf28942..05c013dc 100644
--- a/tests/Resources/Fixtures/config/full.xml
+++ b/tests/Resources/Fixtures/config/full.xml
@@ -62,7 +62,8 @@
             </authentication>
             <cache cache-pool="my_cache_pool" stream-factory="my_other_stream_factory">
                 <config default-ttl="42" cache-lifetime="2592000" hash-algo="sha1" cache-key-generator="null">
-                    <cache-listeners></cache-listeners>
+                    <cache-listeners>my_cache_listener_0</cache-listeners>
+                    <cache-listeners>my_cache_listener_1</cache-listeners>
                     <respect-response-cache-directive>X-Foo</respect-response-cache-directive>
                     <method>GET</method>
                     <blacklisted-paths>@/path/not-to-be/cached@</blacklisted-paths>
diff --git a/tests/Resources/Fixtures/config/full.yml b/tests/Resources/Fixtures/config/full.yml
index 7a91bcf8..1190f9c9 100644
--- a/tests/Resources/Fixtures/config/full.yml
+++ b/tests/Resources/Fixtures/config/full.yml
@@ -82,7 +82,9 @@ httplug:
                   - X-Foo
                 blacklisted_paths:
                   - '@/path/not-to-be/cached@'
-                cache_listeners: []
+                cache_listeners:
+                  - my_cache_listener_0
+                  - my_cache_listener_1
         cookie:
             cookie_jar: my_cookie_jar
         decoder:
diff --git a/tests/Unit/DependencyInjection/ConfigurationTest.php b/tests/Unit/DependencyInjection/ConfigurationTest.php
index bf88a47a..f8cb16b6 100644
--- a/tests/Unit/DependencyInjection/ConfigurationTest.php
+++ b/tests/Unit/DependencyInjection/ConfigurationTest.php
@@ -267,7 +267,10 @@ public function testSupportsAllConfigFormats(): void
                         'cache_key_generator' => null,
                         'respect_response_cache_directives' => ['X-Foo'],
                         'blacklisted_paths' => ['@/path/not-to-be/cached@'],
-                        'cache_listeners' => [],
+                        'cache_listeners' => [
+                            'my_cache_listener_0',
+                            'my_cache_listener_1'
+                        ],
                     ],
                 ],
                 'cookie' => [

From 99029665205824b77a1f9e7dab7be5d50cbc5390 Mon Sep 17 00:00:00 2001
From: Till Hildebrandt <th@facelift-bbt.com>
Date: Thu, 9 Jan 2020 14:04:57 +0100
Subject: [PATCH 10/11] Pretty CF

---
 tests/Unit/DependencyInjection/ConfigurationTest.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/Unit/DependencyInjection/ConfigurationTest.php b/tests/Unit/DependencyInjection/ConfigurationTest.php
index f8cb16b6..8d07b144 100644
--- a/tests/Unit/DependencyInjection/ConfigurationTest.php
+++ b/tests/Unit/DependencyInjection/ConfigurationTest.php
@@ -269,7 +269,7 @@ public function testSupportsAllConfigFormats(): void
                         'blacklisted_paths' => ['@/path/not-to-be/cached@'],
                         'cache_listeners' => [
                             'my_cache_listener_0',
-                            'my_cache_listener_1'
+                            'my_cache_listener_1',
                         ],
                     ],
                 ],

From 1b99d943a112f6d7c315e70e45f74db5cb5e2c8a Mon Sep 17 00:00:00 2001
From: Till Hildebrandt <th@facelift-bbt.com>
Date: Mon, 20 Jan 2020 13:46:13 +0100
Subject: [PATCH 11/11] pull request feedback  - fixed cache listener
 configuration  - proper usage of xml configuration

---
 src/DependencyInjection/Configuration.php | 3 ++-
 tests/Resources/Fixtures/config/full.xml  | 4 ++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index b7bc988c..d3f44f13 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -718,6 +718,7 @@ private function createCachePluginNode()
         $config
             ->fixXmlConfig('method')
             ->fixXmlConfig('respect_response_cache_directive')
+            ->fixXmlConfig('cache_listener')
             ->addDefaultsIfNotSet()
             ->validate()
                 ->ifTrue(function ($config) {
@@ -771,7 +772,7 @@ private function createCachePluginNode()
                 ->end()
                 ->arrayNode('cache_listeners')
                     ->info('A list of service ids to act on the response based on the results of the cache check. Must implement '.CacheListener::class.'. Defaults to an empty array.')
-                    ->beforeNormalization()->ifNull()->thenEmptyArray()->castToArray()->ifEmpty()->thenUnset()->end()
+                    ->beforeNormalization()->castToArray()->end()
                     ->prototype('scalar')
                     ->end()
                 ->end()
diff --git a/tests/Resources/Fixtures/config/full.xml b/tests/Resources/Fixtures/config/full.xml
index 05c013dc..48449964 100644
--- a/tests/Resources/Fixtures/config/full.xml
+++ b/tests/Resources/Fixtures/config/full.xml
@@ -62,8 +62,8 @@
             </authentication>
             <cache cache-pool="my_cache_pool" stream-factory="my_other_stream_factory">
                 <config default-ttl="42" cache-lifetime="2592000" hash-algo="sha1" cache-key-generator="null">
-                    <cache-listeners>my_cache_listener_0</cache-listeners>
-                    <cache-listeners>my_cache_listener_1</cache-listeners>
+                    <cache-listener>my_cache_listener_0</cache-listener>
+                    <cache-listener>my_cache_listener_1</cache-listener>
                     <respect-response-cache-directive>X-Foo</respect-response-cache-directive>
                     <method>GET</method>
                     <blacklisted-paths>@/path/not-to-be/cached@</blacklisted-paths>