SymfonyTest · mbabker · Sep 15, 2026
diff --git a/.gitattributes b/.gitattributes
@@ -1,2 +1,3 @@
 /Tests export-ignore
+/phpstan.neon export-ignore
 /phpunit.xml.dist export-ignore
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
@@ -74,3 +74,43 @@ jobs:
 
             - name: Run tests
               run: vendor/bin/phpunit
+
+    phpstan:
+        name: PHPStan PHP ${{ matrix.php }} (Symfony ${{ matrix.symfony }})
+        runs-on: ubuntu-latest
+        strategy:
+          matrix:
+            php:
+              - '8.5'
+            symfony:
+              - '8.1.*'
+
+        steps:
+          - name: Checkout
+            uses: actions/checkout@v4
+
+          - name: Setup PHP
+            uses: shivammathur/setup-php@v2
+            with:
+              php-version: ${{ matrix.php }}
+              tools: flex
+              coverage: none
+
+          - name: Get Composer Cache Directory
+            id: composer-cache
+            run: echo "dir=$(composer config cache-files-dir)" >> $GITHUB_OUTPUT
+
+          - name: Cache dependencies
+            uses: actions/cache@v4
+            with:
+              path: ${{ steps.composer-cache.outputs.dir }}
+              key: ${{ matrix.php }}-composer-${{ hashFiles('**/composer.json') }}
+              restore-keys: ${{ matrix.php }}-composer-
+
+          - name: Update project dependencies
+            run: composer update --no-progress --ansi --prefer-stable
+            env:
+              SYMFONY_REQUIRE: ${{ matrix.symfony }}
+
+          - name: Run PHPStan
+            run: vendor/bin/phpstan analyze --error-format=github
diff --git a/Partial/Exception/ChildIsNotAnArrayNode.php b/Partial/Exception/ChildIsNotAnArrayNode.php
@@ -6,6 +6,9 @@
 
 class ChildIsNotAnArrayNode extends InvalidNodeNavigation
 {
+    /**
+     * @param non-empty-string $nodeName
+     */
     public function __construct(BaseNode $parentNode, $nodeName)
     {
         parent::__construct(

diff --git a/Partial/Exception/UndefinedChildNode.php b/Partial/Exception/UndefinedChildNode.php
@@ -6,6 +6,9 @@
 
 class UndefinedChildNode extends InvalidNodeNavigation
 {
+    /**
+     * @param non-empty-string $childNodeName
+     */
     public function __construct(NodeInterface $parentNode, $childNodeName)
     {
         parent::__construct(

diff --git a/Partial/PartialNode.php b/Partial/PartialNode.php
@@ -10,23 +10,14 @@
 
 class PartialNode
 {
-    /**
-     * @var \ReflectionProperty
-     */
-    private static $nodeChildrenProperty;
-
-    /**
-     * @var \ReflectionProperty
-     */
-    private static $nodePrototypeProperty;
+    private static ?\ReflectionProperty $nodeChildrenProperty = null;
 
     /**
      * Provide an ArrayNode instance (e.g. the root node created by a TreeBuilder) and a path that is relevant to you,
      * e.g. "dbal.connections": this will strip every node that is not contained in the given path (e.g. the "orm" node
      * would be removed entirely.
      *
-     * @param ArrayNode $node
-     * @param string    $breadcrumbPath
+     * @param string|null $breadcrumbPath
      */
     public static function excludeEverythingNotInBreadcrumbPath(ArrayNode $node, $breadcrumbPath)
     {
@@ -40,7 +31,10 @@ public static function excludeEverythingNotInBreadcrumbPath(ArrayNode $node, $br
     }
 
     /**
-     * @param array $path
+     * @param list<string> $path
+     *
+     * @throws ChildIsNotAnArrayNode if the child node is not an array node
+     * @throws UndefinedChildNode if the node does not have a child in the given path
      */
     public static function excludeEverythingNotInPath(ArrayNode $node, array $path = [])
     {
@@ -71,15 +65,14 @@ public static function excludeEverythingNotInPath(ArrayNode $node, array $path =
     }
 
     /**
-     * @param ArrayNode $node
-     * @param string    $childNodeName
+     * @param non-empty-string $childNodeName
      *
-     * @return NodeInterface
+     * @throws UndefinedChildNode if the node does not have a child with the given name
      */
-    private static function childNode(ArrayNode $node, $childNodeName)
+    private static function childNode(ArrayNode $node, string $childNodeName): NodeInterface
     {
         if ($node instanceof PrototypedArrayNode && '*' === $childNodeName) {
-            return self::nodePrototypeProperty()->getValue($node);
+            return $node->getPrototype();
         }
 
         $children = self::nodeChildrenProperty()->getValue($node);
@@ -94,25 +87,11 @@ private static function childNode(ArrayNode $node, $childNodeName)
         return $children[$childNodeName];
     }
 
-    /**
-     * @return \ReflectionProperty
-     */
-    private static function nodeChildrenProperty()
+    private static function nodeChildrenProperty(): \ReflectionProperty
     {
         return self::$nodeChildrenProperty ??= new \ReflectionProperty(
             ArrayNode::class,
             'children'
         );
     }
-
-    /**
-     * @return \ReflectionProperty
-     */
-    private static function nodePrototypeProperty()
-    {
-        return self::$nodePrototypeProperty ??= new \ReflectionProperty(
-            PrototypedArrayNode::class,
-            'prototype'
-        );
-    }
 }
diff --git a/Partial/PartialProcessor.php b/Partial/PartialProcessor.php
@@ -8,15 +8,23 @@
 
 class PartialProcessor
 {
+    /**
+     * @param string|null $breadcrumbPath
+     *
+     * @return array
+     */
     public function process(ArrayNode $node, $breadcrumbPath, array $configs)
     {
         PartialNode::excludeEverythingNotInBreadcrumbPath($node, $breadcrumbPath);
 
-        $processor = new Processor();
-
-        return $processor->process($node, $configs);
+        return (new Processor())->process($node, $configs);
     }
 
+    /**
+     * @param string|null $breadcrumbPath
+     *
+     * @return array
+     */
     public function processConfiguration(ConfigurationInterface $configuration, $breadcrumbPath, array $configs)
     {
         return $this->process($configuration->getConfigTreeBuilder()->buildTree(), $breadcrumbPath, $configs);

diff --git a/PhpUnit/AbstractConfigurationConstraint.php b/PhpUnit/AbstractConfigurationConstraint.php
@@ -8,22 +8,40 @@
 
 abstract class AbstractConfigurationConstraint extends Constraint
 {
+    /**
+     * @var ConfigurationInterface
+     */
     protected $configuration;
+
+    /**
+     * @var string|null
+     */
     protected $breadcrumbPath;
 
+    /**
+     * @param string|null $breadcrumbPath
+     */
     public function __construct(ConfigurationInterface $configuration, $breadcrumbPath = null)
     {
         $this->configuration = $configuration;
         $this->breadcrumbPath = $breadcrumbPath;
     }
 
+    /**
+     * @return array
+     */
     protected function processConfiguration(array $configurationValues)
     {
-        $processor = new PartialProcessor();
-
-        return $processor->processConfiguration($this->configuration, $this->breadcrumbPath, $configurationValues);
+        return (new PartialProcessor())->processConfiguration($this->configuration, $this->breadcrumbPath, $configurationValues);
     }
 
+    /**
+     * @param mixed $configurationValues
+     *
+     * @return void
+     *
+     * @throws \InvalidArgumentException if the configuration values structure is not the required shape
+     */
     protected function validateConfigurationValuesArray($configurationValues)
     {
         if (!is_array($configurationValues)) {

diff --git a/PhpUnit/ConfigurationTestCaseTrait.php b/PhpUnit/ConfigurationTestCaseTrait.php
@@ -3,18 +3,19 @@
 namespace Matthias\SymfonyConfigTest\PhpUnit;
 
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\Config\Definition\ConfigurationInterface;
 
 /**
  * Add this trait to your Test Case to add the ability of testing your configuration
- * which should implement Symfony\Component\Config\Definition\ConfigurationInterface.
+ * which should implement {@see ConfigurationInterface}.
  */
 trait ConfigurationTestCaseTrait
 {
     /**
      * Return the instance of ConfigurationInterface that should be used by the
      * Configuration-specific assertions in this test-case.
      *
-     * @return \Symfony\Component\Config\Definition\ConfigurationInterface
+     * @return ConfigurationInterface
      */
     abstract protected function getConfiguration();
 
@@ -29,6 +30,8 @@ abstract protected function getConfiguration();
      * @param array       $configurationValues
      * @param string|null $expectedMessage
      * @param bool        $useRegExp
+     *
+     * @return void
      */
     protected function assertConfigurationIsInvalid(array $configurationValues, $expectedMessage = null, $useRegExp = false)
     {
@@ -51,9 +54,11 @@ protected function assertConfigurationIsInvalid(array $configurationValues, $exp
      * to match the exception message using a regular expression.
      *
      * @param array       $configurationValues
-     * @param string      $breadcrumbPath      The path that should be validated, e.g. "doctrine.orm"
+     * @param string|null $breadcrumbPath      The path that should be validated, e.g. "doctrine.orm"
      * @param string|null $expectedMessage
      * @param bool        $useRegExp
+     *
+     * @return void
      */
     protected function assertPartialConfigurationIsInvalid(
         array $configurationValues,
@@ -79,6 +84,8 @@ protected function assertPartialConfigurationIsInvalid(
      *
      * @param array       $configurationValues
      * @param string|null $breadcrumbPath
+     *
+     * @return void
      */
     protected function assertConfigurationIsValid(array $configurationValues, $breadcrumbPath = null)
     {
@@ -99,6 +106,8 @@ protected function assertConfigurationIsValid(array $configurationValues, $bread
      * @param array       $configurationValues
      * @param array       $expectedProcessedConfiguration
      * @param string|null $breadcrumbPath
+     *
+     * @return void
      */
     protected function assertProcessedConfigurationEquals(
         array $configurationValues,

diff --git a/PhpUnit/ConfigurationValuesAreInvalidConstraint.php b/PhpUnit/ConfigurationValuesAreInvalidConstraint.php
@@ -2,6 +2,7 @@
 
 namespace Matthias\SymfonyConfigTest\PhpUnit;
 
+use PHPUnit\Framework\Constraint\Constraint;
 use PHPUnit\Framework\Constraint\ExceptionMessage;
 use PHPUnit\Framework\Constraint\ExceptionMessageIsOrContains;
 use PHPUnit\Framework\Constraint\ExceptionMessageMatchesRegularExpression;
@@ -13,9 +14,21 @@
 
 class ConfigurationValuesAreInvalidConstraint extends AbstractConfigurationConstraint
 {
+    /**
+     * @var string|null
+     */
     private $expectedMessage;
+
+    /**
+     * @var bool
+     */
     private $useRegExp;
 
+    /**
+     * @param string|null $expectedMessage
+     * @param bool        $useRegExp
+     * @param string|null $breadcrumbPath
+     */
     public function __construct(
         ConfigurationInterface $configuration,
         $expectedMessage = null,
@@ -28,6 +41,9 @@ public function __construct(
         $this->useRegExp = $useRegExp;
     }
 
+    /**
+     * {@inheritdoc}
+     */
     public function evaluate($other, $description = '', $returnResult = false): ?bool
     {
         $this->validateConfigurationValuesArray($other);
@@ -44,6 +60,7 @@ public function evaluate($other, $description = '', $returnResult = false): ?boo
 
         $this->fail($other, $description);
 
+        /** @phpstan-ignore deadCode.unreachable (legacy B/C layer) */
         return null;
     }
 
@@ -58,7 +75,7 @@ public function toString(): string
         return $toString;
     }
 
-    private function evaluateException(\Exception $exception, $description, $returnResult)
+    private function evaluateException(\Exception $exception, string $description = '', bool $returnResult = false): ?bool
     {
         if ($this->expectedMessage === null) {
             return true;
@@ -68,7 +85,7 @@ private function evaluateException(\Exception $exception, $description, $returnR
             ->evaluate($exception->getMessage(), $description, $returnResult);
     }
 
-    private function createPhpUnitConstraint()
+    private function createPhpUnitConstraint(): Constraint
     {
         if ($this->useRegExp) {
             // Available since PHPUnit 10.0.15
@@ -78,10 +95,12 @@ private function createPhpUnitConstraint()
 
             // Available between PHPUnit 10.0.0 and 10.0.14 (inclusive)
             if (class_exists(MessageMatchesRegularExpression::class)) {
+                /** @phpstan-ignore return.type (legacy B/C layer) */
                 return new MessageMatchesRegularExpression('exception', $this->expectedMessage);
             }
 
             // Available in PHPUnit 9.6
+            /** @phpstan-ignore class.notFound,return.type (legacy B/C layer) */
             return new ExceptionMessageRegularExpression($this->expectedMessage);
         }
 
@@ -92,10 +111,12 @@ private function createPhpUnitConstraint()
 
         // Available between PHPUnit 10.0.0 and 10.0.14 (inclusive)
         if (class_exists(MessageIsOrContains::class)) {
+            /** @phpstan-ignore return.type (legacy B/C layer) */
             return new MessageIsOrContains('exception', $this->expectedMessage);
         }
 
         // Available in PHPUnit 9.6
+        /** @phpstan-ignore class.notFound,return.type (legacy B/C layer) */
         return new ExceptionMessage($this->expectedMessage);
     }
 }
diff --git a/PhpUnit/ConfigurationValuesAreValidConstraint.php b/PhpUnit/ConfigurationValuesAreValidConstraint.php
@@ -2,16 +2,10 @@
 
 namespace Matthias\SymfonyConfigTest\PhpUnit;
 
-use Symfony\Component\Config\Definition\ConfigurationInterface;
 use Symfony\Component\Config\Definition\Exception\InvalidConfigurationException;
 
 class ConfigurationValuesAreValidConstraint extends AbstractConfigurationConstraint
 {
-    public function __construct(ConfigurationInterface $configuration, $breadcrumbPath = null)
-    {
-        parent::__construct($configuration, $breadcrumbPath);
-    }
-
     public function evaluate($other, $description = '', $returnResult = false): ?bool
     {
         $this->validateConfigurationValuesArray($other);