diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 637d09c..52450e5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -42,7 +42,7 @@ jobs:
       run: echo "::set-output name=date::$(date +'%Y-%m')"
 
     - name: Cache composer dependencies
-      uses: actions/cache@v1
+      uses: actions/cache@v4
       with:
         path: ${{ steps.composer-cache.outputs.dir }}
         key: ${{ runner.os }}-composer-${{ steps.key-date.outputs.date }}-${{ hashFiles('composer.json') }}-${{ matrix.prefer-lowest }}
diff --git a/src/AssetConfig.php b/src/AssetConfig.php
index 4bec41b..5a610f6 100644
--- a/src/AssetConfig.php
+++ b/src/AssetConfig.php
@@ -255,8 +255,8 @@ protected function resolveExtends(): void
             if (!$parentConfig) {
                 return $config;
             }
-            $config['files'] = array_merge($parentConfig['files'], $config['files']);
-            $config['filters'] = array_merge($parentConfig['filters'], $config['filters']);
+            $config['files'] = array_unique(array_merge($parentConfig['files'], $config['files']));
+            $config['filters'] = array_unique(array_merge($parentConfig['filters'], $config['filters']));
             $config['theme'] = $parentConfig['theme'] || $config['theme'];
 
             return $config;
diff --git a/src/AssetProcess.php b/src/AssetProcess.php
index c2f0b0e..0120dfe 100644
--- a/src/AssetProcess.php
+++ b/src/AssetProcess.php
@@ -105,7 +105,7 @@ public function run(?string $input = null): string
             $descriptorSpec,
             $pipes,
             null,
-            $this->_env
+            $this->_env,
         );
         if (is_resource($process)) {
             fwrite($pipes[0], $input);
diff --git a/src/Cli/BuildTask.php b/src/Cli/BuildTask.php
index 17af4c2..2316e57 100644
--- a/src/Cli/BuildTask.php
+++ b/src/Cli/BuildTask.php
@@ -64,7 +64,7 @@ protected function addArguments(): void
                 'description' => 'The config file to use.',
                 'required' => true,
             ],
-            ]
+            ],
         );
     }
 
diff --git a/src/Cli/ClearTask.php b/src/Cli/ClearTask.php
index a5b88be..695e344 100644
--- a/src/Cli/ClearTask.php
+++ b/src/Cli/ClearTask.php
@@ -49,7 +49,7 @@ protected function addArguments(): void
                 'description' => 'The config file to use.',
                 'required' => true,
             ],
-            ]
+            ],
         );
     }
 
diff --git a/src/Factory.php b/src/Factory.php
index e546bbc..8233c70 100644
--- a/src/Factory.php
+++ b/src/Factory.php
@@ -77,7 +77,7 @@ public function cachedCompiler(string $outputDir = '', bool $debug = false): Cac
     {
         return new CachedCompiler(
             $this->cacher($outputDir),
-            $this->compiler($debug)
+            $this->compiler($debug),
         );
     }
 
diff --git a/src/Filter/ClosureCompiler.php b/src/Filter/ClosureCompiler.php
index bd6aa12..2623a97 100644
--- a/src/Filter/ClosureCompiler.php
+++ b/src/Filter/ClosureCompiler.php
@@ -136,7 +136,7 @@ protected function _query(string $content, array $args = []): string|bool
             CURLOPT_RETURNTRANSFER => 1,
             CURLOPT_HEADER => 0,
             CURLOPT_FOLLOWLOCATION => 0,
-            ]
+            ],
         );
 
         $output = curl_exec($ch);
diff --git a/src/Filter/CssDependencyTrait.php b/src/Filter/CssDependencyTrait.php
index d636149..69ad149 100644
--- a/src/Filter/CssDependencyTrait.php
+++ b/src/Filter/CssDependencyTrait.php
@@ -147,7 +147,7 @@ protected function _prependPrefixToFilename(string $name): string
         return str_replace(
             $ds . $filename,
             $ds . $this->optionalDependencyPrefix . $filename,
-            $name
+            $name,
         );
     }
 }
diff --git a/src/Filter/FilterRegistry.php b/src/Filter/FilterRegistry.php
index 13933fa..dee6f05 100644
--- a/src/Filter/FilterRegistry.php
+++ b/src/Filter/FilterRegistry.php
@@ -114,7 +114,7 @@ public function collection(AssetTarget $target): FilterCollection
                 [
                 'target' => $target->name(),
                 'paths' => $target->paths(),
-                ]
+                ],
             );
             $filters[] = $copy;
         }
diff --git a/src/Filter/Hogan.php b/src/Filter/Hogan.php
index 896067d..670a347 100644
--- a/src/Filter/Hogan.php
+++ b/src/Filter/Hogan.php
@@ -106,7 +106,7 @@ protected function _generateScript(string $file, string $filename, string $input
             json_encode($input),
             json_encode($config),
             $id,
-            $filepath
+            $filepath,
         );
         file_put_contents($file, $contents);
     }
diff --git a/src/Filter/ImportInline.php b/src/Filter/ImportInline.php
index 7eb7f76..f0f3284 100644
--- a/src/Filter/ImportInline.php
+++ b/src/Filter/ImportInline.php
@@ -53,7 +53,7 @@ public function input(string $filename, string $content): string
         return preg_replace_callback(
             $this->_pattern,
             [$this, '_replace'],
-            $content
+            $content,
         );
     }
 
diff --git a/src/Filter/JSqueezeFilter.php b/src/Filter/JSqueezeFilter.php
index 9f47ad1..abb7b18 100644
--- a/src/Filter/JSqueezeFilter.php
+++ b/src/Filter/JSqueezeFilter.php
@@ -58,7 +58,7 @@ public function output(string $target, string $content): string
             $content,
             $this->_settings['singleLine'],
             $this->_settings['keepImportantComments'],
-            $this->_settings['specialVarRx']
+            $this->_settings['specialVarRx'],
         );
     }
 }
diff --git a/src/Filter/LessCss.php b/src/Filter/LessCss.php
index 1a8cb54..c5d8e3d 100644
--- a/src/Filter/LessCss.php
+++ b/src/Filter/LessCss.php
@@ -75,7 +75,7 @@ protected function _generateScript(string $file, string $content): void
 JS;
         file_put_contents(
             $file,
-            sprintf($text, str_replace('\/*', '', json_encode($this->_settings['paths'])), json_encode($content))
+            sprintf($text, str_replace('\/*', '', json_encode($this->_settings['paths'])), json_encode($content)),
         );
     }
 }
diff --git a/src/Filter/LessDotPHP.php b/src/Filter/LessDotPHP.php
index ca86592..a08752a 100644
--- a/src/Filter/LessDotPHP.php
+++ b/src/Filter/LessDotPHP.php
@@ -49,7 +49,7 @@ public function input(string $filename, string $content): string
         }
         if (!class_exists('\Less_Parser')) {
             throw new Exception(
-                'Cannot not load "\Less_Parser" class. Make sure https://github.com/oyejorge/less.php is installed.'
+                'Cannot not load "\Less_Parser" class. Make sure https://github.com/oyejorge/less.php is installed.',
             );
         }
         $parser = new Less_Parser();
diff --git a/src/Filter/Sprockets.php b/src/Filter/Sprockets.php
index 9102a2f..814c465 100644
--- a/src/Filter/Sprockets.php
+++ b/src/Filter/Sprockets.php
@@ -73,7 +73,7 @@ public function input(string $filename, string $content): string
         return preg_replace_callback(
             $this->_pattern,
             [$this, '_replace'],
-            $content
+            $content,
         );
     }
 
diff --git a/tests/TestCase/AssetConfigTest.php b/tests/TestCase/AssetConfigTest.php
index 19e8d1e..1b4c0ed 100644
--- a/tests/TestCase/AssetConfigTest.php
+++ b/tests/TestCase/AssetConfigTest.php
@@ -80,7 +80,7 @@ public function testLoadUpdatesModifiedTime()
         $this->assertEquals(
             filemtime($this->_themeConfig),
             $config->modifiedTime(),
-            'Reflects last updated config file'
+            'Reflects last updated config file',
         );
     }
 
@@ -148,7 +148,7 @@ public function testAddTarget()
             'testing.js',
             [
             'files' => ['one.js', 'two.js'],
-            ]
+            ],
         );
         $this->assertEquals(['one.js', 'two.js'], $this->config->files('testing.js'));
     }
@@ -161,11 +161,11 @@ public function testAddTargetThemed()
             'files' => ['one.js', 'two.js'],
             'filters' => ['uglify'],
             'theme' => true,
-            ]
+            ],
         );
         $this->assertEquals(
             ['one.js', 'two.js'],
-            $this->config->files('testing-two.js')
+            $this->config->files('testing-two.js'),
         );
         $this->assertTrue($this->config->isThemed('testing-two.js'));
     }
@@ -176,14 +176,14 @@ public function testRequires()
             'testing.js',
             [
             'files' => ['one.js', 'two.js'],
-            ]
+            ],
         );
         $this->config->addTarget(
             'child.js',
             [
             'files' => ['one.js', 'two.js'],
             'require' => 'base.js',
-            ]
+            ],
         );
         $this->assertEquals([], $this->config->requires('testing.js'));
         $this->assertEquals(['base.js'], $this->config->requires('child.js'));
diff --git a/tests/TestCase/Cli/BuildTaskTest.php b/tests/TestCase/Cli/BuildTaskTest.php
index 6a18c00..f1ca711 100644
--- a/tests/TestCase/Cli/BuildTaskTest.php
+++ b/tests/TestCase/Cli/BuildTaskTest.php
@@ -36,7 +36,7 @@ protected function setUp(): void
 
         $config = AssetConfig::buildFromIniFile(
             APP . 'config/integration.ini',
-            ['WEBROOT' => TMP]
+            ['WEBROOT' => TMP],
         );
         $this->task = new BuildTask($cli, $config);
         $this->cli = $cli;
diff --git a/tests/TestCase/Cli/ClearTaskTest.php b/tests/TestCase/Cli/ClearTaskTest.php
index 7da9732..3dacdaa 100644
--- a/tests/TestCase/Cli/ClearTaskTest.php
+++ b/tests/TestCase/Cli/ClearTaskTest.php
@@ -36,7 +36,7 @@ protected function setUp(): void
 
         $config = AssetConfig::buildFromIniFile(
             APP . 'config/integration.ini',
-            ['WEBROOT' => TMP]
+            ['WEBROOT' => TMP],
         );
         $this->task = new ClearTask($cli, $config);
         $this->cli = $cli;
diff --git a/tests/TestCase/FactoryTest.php b/tests/TestCase/FactoryTest.php
index e34b6cc..1548442 100644
--- a/tests/TestCase/FactoryTest.php
+++ b/tests/TestCase/FactoryTest.php
@@ -88,11 +88,11 @@ public function testTargetCallbackProvider()
 
         $this->assertEquals(
             APP . 'js/classes/base_class.js',
-            $result[0]->path()
+            $result[0]->path(),
         );
         $this->assertEquals(
             APP . 'js/classes/nested_class.js',
-            $result[1]->path()
+            $result[1]->path(),
         );
     }
 
@@ -109,19 +109,19 @@ public function testTargetCallbackProviderAssetOrdering()
 
         $this->assertEquals(
             APP . 'js/library_file.js',
-            $result[0]->path()
+            $result[0]->path(),
         );
         $this->assertEquals(
             APP . 'js/classes/base_class.js',
-            $result[1]->path()
+            $result[1]->path(),
         );
         $this->assertEquals(
             APP . 'js/classes/nested_class.js',
-            $result[2]->path()
+            $result[2]->path(),
         );
         $this->assertEquals(
             APP . 'js/local_script.js',
-            $result[3]->path()
+            $result[3]->path(),
         );
     }
 
@@ -186,7 +186,7 @@ public function testTargetWithRequireIntegration()
         $this->assertStringContainsString(
             '//= require "local_script"',
             $contents,
-            'Sprockets should not be applied to intermediate build files'
+            'Sprockets should not be applied to intermediate build files',
         );
     }
 
@@ -196,7 +196,7 @@ public function testAssetCollection()
             $this->integrationFile,
             [
             'WEBROOT' => TMP,
-            ]
+            ],
         );
         $factory = new Factory($config);
         $collection = $factory->assetCollection();
@@ -233,15 +233,15 @@ public function testAssetCreationWithAdditionalPath()
         $this->assertCount(3, $files);
         $this->assertEquals(
             APP . 'js/base.js',
-            $files[0]->path()
+            $files[0]->path(),
         );
         $this->assertEquals(
             APP . 'js/library_file.js',
-            $files[1]->path()
+            $files[1]->path(),
         );
         $this->assertEquals(
             APP . 'js/classes/base_class.js',
-            $files[2]->path()
+            $files[2]->path(),
         );
     }
 
@@ -259,7 +259,7 @@ public function testAssetCollectionGlob()
         $this->assertEquals(
             [APP . 'js/', APP . 'js/classes/', APP . 'js/secondary/'],
             $asset->paths(),
-            'Should have expanded paths'
+            'Should have expanded paths',
         );
 
         $files = $asset->files();
diff --git a/tests/TestCase/Filter/LessCssTest.php b/tests/TestCase/Filter/LessCssTest.php
index 3efed7e..75fd6e4 100644
--- a/tests/TestCase/Filter/LessCssTest.php
+++ b/tests/TestCase/Filter/LessCssTest.php
@@ -33,7 +33,7 @@ protected function setUp(): void
         $this->filter->settings(
             [
             'paths' => [$this->_cssDir],
-            ]
+            ],
         );
     }
 
diff --git a/tests/TestCase/Middleware/AssetMiddlewareTest.php b/tests/TestCase/Middleware/AssetMiddlewareTest.php
index 5bd38a2..9ad75a5 100644
--- a/tests/TestCase/Middleware/AssetMiddlewareTest.php
+++ b/tests/TestCase/Middleware/AssetMiddlewareTest.php
@@ -34,7 +34,7 @@ protected function setUp(): void
         $this->middleware = new AssetMiddleware(
             $this->config,
             sys_get_temp_dir() . DIRECTORY_SEPARATOR,
-            '/assets/'
+            '/assets/',
         );
     }
 
@@ -43,7 +43,7 @@ public function testInvokeIncorrectPrefix()
         $request = ServerRequestFactory::fromGlobals(
             [
             'REQUEST_URI' => '/wrong/assets/path',
-            ]
+            ],
         );
         $response = new Response();
         $next = function ($req, $res) {
@@ -58,7 +58,7 @@ public function testInvokeMissingAssetFile()
         $request = ServerRequestFactory::fromGlobals(
             [
             'REQUEST_URI' => '/assets/nope.js',
-            ]
+            ],
         );
         $response = new Response();
         $next = function ($req, $res) {
@@ -75,13 +75,13 @@ public function testInvokeFailedBuild()
             'invalid.css',
             [
             'files' => [APP . 'invalid.css'],
-            ]
+            ],
         );
 
         $request = ServerRequestFactory::fromGlobals(
             [
             'REQUEST_URI' => '/assets/invalid.css',
-            ]
+            ],
         );
         $response = new Response();
         $next = function ($req, $res) {
@@ -99,7 +99,7 @@ public function testInvokeCacheRead()
         $request = ServerRequestFactory::fromGlobals(
             [
             'REQUEST_URI' => '/assets/all.css',
-            ]
+            ],
         );
         $response = new Response();
         $next = function ($req, $res) {
@@ -119,7 +119,7 @@ public function testInvokeSuccessfulBuild()
         $request = ServerRequestFactory::fromGlobals(
             [
             'REQUEST_URI' => '/assets/all.css',
-            ]
+            ],
         );
         $response = new Response();
         $next = function ($req, $res) {
@@ -151,7 +151,7 @@ public function testBuildFileContentTypes($uri, $expected)
         $request = ServerRequestFactory::fromGlobals(
             [
             'REQUEST_URI' => $uri,
-            ]
+            ],
         );
 
         $response = new Response();
diff --git a/tests/TestCase/Output/AssetCacherTest.php b/tests/TestCase/Output/AssetCacherTest.php
index 839ef66..693c72c 100644
--- a/tests/TestCase/Output/AssetCacherTest.php
+++ b/tests/TestCase/Output/AssetCacherTest.php
@@ -40,7 +40,7 @@ protected function setUp(): void
             $this->files,
             [],
             [],
-            true
+            true,
         );
         $filter = $this->getMockBuilder('MiniAsset\Filter\FilterInterface')->getMock();
         $filter->method('getDependencies')
diff --git a/tests/TestCase/Output/CachedCompilerTest.php b/tests/TestCase/Output/CachedCompilerTest.php
index a4a1018..ae301bc 100644
--- a/tests/TestCase/Output/CachedCompilerTest.php
+++ b/tests/TestCase/Output/CachedCompilerTest.php
@@ -44,7 +44,7 @@ protected function setUp(): void
             [
             $this->_testFiles . 'js' . DS,
             $this->_testFiles . 'js' . DS . '*',
-            ]
+            ],
         );
         $this->config->paths(
             'css',
@@ -52,7 +52,7 @@ protected function setUp(): void
             [
             $this->_testFiles . 'css' . DS,
             $this->_testFiles . 'css' . DS . '*',
-            ]
+            ],
         );
 
         if (file_exists(TMP . '/all.css')) {
diff --git a/tests/TestCase/Output/CompilerTest.php b/tests/TestCase/Output/CompilerTest.php
index fdc1b6e..158d7c6 100644
--- a/tests/TestCase/Output/CompilerTest.php
+++ b/tests/TestCase/Output/CompilerTest.php
@@ -44,7 +44,7 @@ protected function setUp(): void
             [
             $this->_testFiles . 'js' . DS,
             $this->_testFiles . 'js' . DS . '*',
-            ]
+            ],
         );
         $this->config->paths(
             'css',
@@ -52,7 +52,7 @@ protected function setUp(): void
             [
             $this->_testFiles . 'css' . DS,
             $this->_testFiles . 'css' . DS . '*',
-            ]
+            ],
         );
     }