Initial Drupal 11 with DDEV setup

vendor/symfony/serializer/Mapping/Loader/AttributeLoader.php

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+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Serializer\Mapping\Loader;
+
+use Symfony\Component\Serializer\Attribute\Context;
+use Symfony\Component\Serializer\Attribute\DiscriminatorMap;
+use Symfony\Component\Serializer\Attribute\Groups;
+use Symfony\Component\Serializer\Attribute\Ignore;
+use Symfony\Component\Serializer\Attribute\MaxDepth;
+use Symfony\Component\Serializer\Attribute\SerializedName;
+use Symfony\Component\Serializer\Attribute\SerializedPath;
+use Symfony\Component\Serializer\Exception\MappingException;
+use Symfony\Component\Serializer\Mapping\AttributeMetadata;
+use Symfony\Component\Serializer\Mapping\AttributeMetadataInterface;
+use Symfony\Component\Serializer\Mapping\ClassDiscriminatorMapping;
+use Symfony\Component\Serializer\Mapping\ClassMetadataInterface;
+
+/**
+ * Loader for PHP attributes.
+ *
+ * @author Kévin Dunglas <dunglas@gmail.com>
+ * @author Alexander M. Turek <me@derrabus.de>
+ * @author Alexandre Daubois <alex.daubois@gmail.com>
+ */
+class AttributeLoader implements LoaderInterface
+{
+    private const KNOWN_ATTRIBUTES = [
+        DiscriminatorMap::class,
+        Groups::class,
+        Ignore::class,
+        MaxDepth::class,
+        SerializedName::class,
+        SerializedPath::class,
+        Context::class,
+    ];
+
+    public function __construct()
+    {
+    }
+
+    public function loadClassMetadata(ClassMetadataInterface $classMetadata): bool
+    {
+        $reflectionClass = $classMetadata->getReflectionClass();
+        $className = $reflectionClass->name;
+        $loaded = false;
+        $classGroups = [];
+        $classContextAttribute = null;
+
+        $attributesMetadata = $classMetadata->getAttributesMetadata();
+
+        foreach ($this->loadAttributes($reflectionClass) as $attribute) {
+            match (true) {
+                $attribute instanceof DiscriminatorMap => $classMetadata->setClassDiscriminatorMapping(new ClassDiscriminatorMapping($attribute->getTypeProperty(), $attribute->getMapping(), $attribute->getDefaultType())),
+                $attribute instanceof Groups => $classGroups = $attribute->getGroups(),
+                $attribute instanceof Context => $classContextAttribute = $attribute,
+                default => null,
+            };
+        }
+
+        foreach ($reflectionClass->getProperties() as $property) {
+            if (!isset($attributesMetadata[$property->name])) {
+                $attributesMetadata[$property->name] = new AttributeMetadata($property->name);
+                $classMetadata->addAttributeMetadata($attributesMetadata[$property->name]);
+            }
+
+            $attributeMetadata = $attributesMetadata[$property->name];
+            if ($property->getDeclaringClass()->name === $className) {
+                if ($classContextAttribute) {
+                    $this->setAttributeContextsForGroups($classContextAttribute, $attributeMetadata);
+                }
+
+                foreach ($classGroups as $group) {
+                    $attributeMetadata->addGroup($group);
+                }
+
+                foreach ($this->loadAttributes($property) as $attribute) {
+                    $loaded = true;
+
+                    if ($attribute instanceof Groups) {
+                        foreach ($attribute->getGroups() as $group) {
+                            $attributeMetadata->addGroup($group);
+                        }
+
+                        continue;
+                    }
+
+                    match (true) {
+                        $attribute instanceof MaxDepth => $attributeMetadata->setMaxDepth($attribute->getMaxDepth()),
+                        $attribute instanceof SerializedName => $attributeMetadata->setSerializedName($attribute->getSerializedName()),
+                        $attribute instanceof SerializedPath => $attributeMetadata->setSerializedPath($attribute->getSerializedPath()),
+                        $attribute instanceof Ignore => $attributeMetadata->setIgnore(true),
+                        $attribute instanceof Context => $this->setAttributeContextsForGroups($attribute, $attributeMetadata),
+                        default => null,
+                    };
+                }
+            }
+        }
+
+        foreach ($reflectionClass->getMethods() as $method) {
+            if ($method->getDeclaringClass()->name !== $className) {
+                continue;
+            }
+
+            if (0 === stripos($method->name, 'get') && $method->getNumberOfRequiredParameters()) {
+                continue; /*  matches the BC behavior in `Symfony\Component\Serializer\Normalizer\ObjectNormalizer::extractAttributes` */
+            }
+
+            $accessorOrMutator = preg_match('/^(get|is|has|set)(.+)$/i', $method->name, $matches);
+            if ($accessorOrMutator && !ctype_lower($matches[2][0])) {
+                $attributeName = lcfirst($matches[2]);
+
+                if (isset($attributesMetadata[$attributeName])) {
+                    $attributeMetadata = $attributesMetadata[$attributeName];
+                } else {
+                    $attributesMetadata[$attributeName] = $attributeMetadata = new AttributeMetadata($attributeName);
+                    $classMetadata->addAttributeMetadata($attributeMetadata);
+                }
+            }
+
+            foreach ($this->loadAttributes($method) as $attribute) {
+                if ($attribute instanceof Groups) {
+                    if (!$accessorOrMutator) {
+                        throw new MappingException(\sprintf('Groups on "%s::%s()" cannot be added. Groups can only be added on methods beginning with "get", "is", "has" or "set".', $className, $method->name));
+                    }
+
+                    foreach ($attribute->getGroups() as $group) {
+                        $attributeMetadata->addGroup($group);
+                    }
+                } elseif ($attribute instanceof MaxDepth) {
+                    if (!$accessorOrMutator) {
+                        throw new MappingException(\sprintf('MaxDepth on "%s::%s()" cannot be added. MaxDepth can only be added on methods beginning with "get", "is", "has" or "set".', $className, $method->name));
+                    }
+
+                    $attributeMetadata->setMaxDepth($attribute->getMaxDepth());
+                } elseif ($attribute instanceof SerializedName) {
+                    if (!$accessorOrMutator) {
+                        throw new MappingException(\sprintf('SerializedName on "%s::%s()" cannot be added. SerializedName can only be added on methods beginning with "get", "is", "has" or "set".', $className, $method->name));
+                    }
+
+                    $attributeMetadata->setSerializedName($attribute->getSerializedName());
+                } elseif ($attribute instanceof SerializedPath) {
+                    if (!$accessorOrMutator) {
+                        throw new MappingException(\sprintf('SerializedPath on "%s::%s()" cannot be added. SerializedPath can only be added on methods beginning with "get", "is", "has" or "set".', $className, $method->name));
+                    }
+
+                    $attributeMetadata->setSerializedPath($attribute->getSerializedPath());
+                } elseif ($attribute instanceof Ignore) {
+                    if ($accessorOrMutator) {
+                        $attributeMetadata->setIgnore(true);
+                    }
+                } elseif ($attribute instanceof Context) {
+                    if (!$accessorOrMutator) {
+                        throw new MappingException(\sprintf('Context on "%s::%s()" cannot be added. Context can only be added on methods beginning with "get", "is", "has" or "set".', $className, $method->name));
+                    }
+
+                    $this->setAttributeContextsForGroups($attribute, $attributeMetadata);
+                }
+
+                $loaded = true;
+            }
+        }
+
+        return $loaded;
+    }
+
+    private function loadAttributes(\ReflectionMethod|\ReflectionClass|\ReflectionProperty $reflector): iterable
+    {
+        foreach ($reflector->getAttributes() as $attribute) {
+            if ($this->isKnownAttribute($attribute->getName())) {
+                try {
+                    yield $attribute->newInstance();
+                } catch (\Error $e) {
+                    if (\Error::class !== $e::class) {
+                        throw $e;
+                    }
+                    $on = match (true) {
+                        $reflector instanceof \ReflectionClass => ' on class '.$reflector->name,
+                        $reflector instanceof \ReflectionMethod => \sprintf(' on "%s::%s()"', $reflector->getDeclaringClass()->name, $reflector->name),
+                        $reflector instanceof \ReflectionProperty => \sprintf(' on "%s::$%s"', $reflector->getDeclaringClass()->name, $reflector->name),
+                        default => '',
+                    };
+
+                    throw new MappingException(\sprintf('Could not instantiate attribute "%s"%s.', $attribute->getName(), $on), 0, $e);
+                }
+            }
+        }
+    }
+
+    private function setAttributeContextsForGroups(Context $attribute, AttributeMetadataInterface $attributeMetadata): void
+    {
+        $context = $attribute->getContext();
+        $groups = $attribute->getGroups();
+        $normalizationContext = $attribute->getNormalizationContext();
+        $denormalizationContext = $attribute->getDenormalizationContext();
+
+        if ($normalizationContext || $context) {
+            $attributeMetadata->setNormalizationContextForGroups($normalizationContext ?: $context, $groups);
+        }
+
+        if ($denormalizationContext || $context) {
+            $attributeMetadata->setDenormalizationContextForGroups($denormalizationContext ?: $context, $groups);
+        }
+    }
+
+    private function isKnownAttribute(string $attributeName): bool
+    {
+        foreach (self::KNOWN_ATTRIBUTES as $knownAttribute) {
+            if (is_a($attributeName, $knownAttribute, true)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}

vendor/symfony/serializer/Mapping/Loader/FileLoader.php

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+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Serializer\Mapping\Loader;
+
+use Symfony\Component\Serializer\Exception\MappingException;
+
+/**
+ * Base class for all file based loaders.
+ *
+ * @author Kévin Dunglas <dunglas@gmail.com>
+ */
+abstract class FileLoader implements LoaderInterface
+{
+    /**
+     * @param string $file The mapping file to load
+     *
+     * @throws MappingException if the mapping file does not exist or is not readable
+     */
+    public function __construct(
+        protected string $file,
+    ) {
+        if (!is_file($file)) {
+            throw new MappingException(\sprintf('The mapping file "%s" does not exist.', $file));
+        }
+
+        if (!is_readable($file)) {
+            throw new MappingException(\sprintf('The mapping file "%s" is not readable.', $file));
+        }
+    }
+}

vendor/symfony/serializer/Mapping/Loader/LoaderChain.php

@@ -0,0 +1,64 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Serializer\Mapping\Loader;
+
+use Symfony\Component\Serializer\Exception\MappingException;
+use Symfony\Component\Serializer\Mapping\ClassMetadataInterface;
+
+/**
+ * Calls multiple {@link LoaderInterface} instances in a chain.
+ *
+ * This class accepts multiple instances of LoaderInterface to be passed to the
+ * constructor. When {@link loadClassMetadata()} is called, the same method is called
+ * in <em>all</em> of these loaders, regardless of whether any of them was
+ * successful or not.
+ *
+ * @author Bernhard Schussek <bschussek@gmail.com>
+ * @author Kévin Dunglas <dunglas@gmail.com>
+ */
+class LoaderChain implements LoaderInterface
+{
+    /**
+     * Accepts a list of LoaderInterface instances.
+     *
+     * @param LoaderInterface[] $loaders An array of LoaderInterface instances
+     *
+     * @throws MappingException If any of the loaders does not implement LoaderInterface
+     */
+    public function __construct(private readonly array $loaders)
+    {
+        foreach ($loaders as $loader) {
+            if (!$loader instanceof LoaderInterface) {
+                throw new MappingException(\sprintf('Class "%s" is expected to implement LoaderInterface.', get_debug_type($loader)));
+            }
+        }
+    }
+
+    public function loadClassMetadata(ClassMetadataInterface $metadata): bool
+    {
+        $success = false;
+
+        foreach ($this->loaders as $loader) {
+            $success = $loader->loadClassMetadata($metadata) || $success;
+        }
+
+        return $success;
+    }
+
+    /**
+     * @return LoaderInterface[]
+     */
+    public function getLoaders(): array
+    {
+        return $this->loaders;
+    }
+}

vendor/symfony/serializer/Mapping/Loader/LoaderInterface.php

@@ -0,0 +1,24 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Serializer\Mapping\Loader;
+
+use Symfony\Component\Serializer\Mapping\ClassMetadataInterface;
+
+/**
+ * Loads {@link ClassMetadataInterface}.
+ *
+ * @author Kévin Dunglas <dunglas@gmail.com>
+ */
+interface LoaderInterface
+{
+    public function loadClassMetadata(ClassMetadataInterface $classMetadata): bool;
+}

vendor/symfony/serializer/Mapping/Loader/XmlFileLoader.php

@@ -0,0 +1,183 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Serializer\Mapping\Loader;
+
+use Symfony\Component\Config\Util\XmlUtils;
+use Symfony\Component\PropertyAccess\Exception\InvalidPropertyPathException;
+use Symfony\Component\PropertyAccess\PropertyPath;
+use Symfony\Component\Serializer\Exception\MappingException;
+use Symfony\Component\Serializer\Mapping\AttributeMetadata;
+use Symfony\Component\Serializer\Mapping\ClassDiscriminatorMapping;
+use Symfony\Component\Serializer\Mapping\ClassMetadataInterface;
+
+/**
+ * Loads XML mapping files.
+ *
+ * @author Kévin Dunglas <dunglas@gmail.com>
+ */
+class XmlFileLoader extends FileLoader
+{
+    /**
+     * An array of {@class \SimpleXMLElement} instances.
+     *
+     * @var \SimpleXMLElement[]|null
+     */
+    private ?array $classes = null;
+
+    public function loadClassMetadata(ClassMetadataInterface $classMetadata): bool
+    {
+        if (!$this->classes ??= $this->getClassesFromXml()) {
+            return false;
+        }
+
+        $attributesMetadata = $classMetadata->getAttributesMetadata();
+
+        if (isset($this->classes[$classMetadata->getName()])) {
+            $xml = $this->classes[$classMetadata->getName()];
+
+            foreach ($xml->attribute as $attribute) {
+                $attributeName = (string) $attribute['name'];
+
+                if (isset($attributesMetadata[$attributeName])) {
+                    $attributeMetadata = $attributesMetadata[$attributeName];
+                } else {
+                    $attributeMetadata = new AttributeMetadata($attributeName);
+                    $classMetadata->addAttributeMetadata($attributeMetadata);
+                }
+
+                foreach ($attribute->group as $group) {
+                    $attributeMetadata->addGroup((string) $group);
+                }
+
+                if (isset($attribute['max-depth'])) {
+                    $attributeMetadata->setMaxDepth((int) $attribute['max-depth']);
+                }
+
+                if (isset($attribute['serialized-name'])) {
+                    $attributeMetadata->setSerializedName((string) $attribute['serialized-name']);
+                }
+
+                if (isset($attribute['serialized-path'])) {
+                    try {
+                        $attributeMetadata->setSerializedPath(new PropertyPath((string) $attribute['serialized-path']));
+                    } catch (InvalidPropertyPathException) {
+                        throw new MappingException(\sprintf('The "serialized-path" value must be a valid property path for the attribute "%s" of the class "%s".', $attributeName, $classMetadata->getName()));
+                    }
+                }
+
+                if (isset($attribute['ignore'])) {
+                    $attributeMetadata->setIgnore(XmlUtils::phpize($attribute['ignore']));
+                }
+
+                foreach ($attribute->context as $node) {
+                    $groups = (array) $node->group;
+                    $context = $this->parseContext($node->entry);
+                    $attributeMetadata->setNormalizationContextForGroups($context, $groups);
+                    $attributeMetadata->setDenormalizationContextForGroups($context, $groups);
+                }
+
+                foreach ($attribute->normalization_context as $node) {
+                    $groups = (array) $node->group;
+                    $context = $this->parseContext($node->entry);
+                    $attributeMetadata->setNormalizationContextForGroups($context, $groups);
+                }
+
+                foreach ($attribute->denormalization_context as $node) {
+                    $groups = (array) $node->group;
+                    $context = $this->parseContext($node->entry);
+                    $attributeMetadata->setDenormalizationContextForGroups($context, $groups);
+                }
+            }
+
+            if (isset($xml->{'discriminator-map'})) {
+                $mapping = [];
+                foreach ($xml->{'discriminator-map'}->mapping as $element) {
+                    $elementAttributes = $element->attributes();
+                    $mapping[(string) $elementAttributes->type] = (string) $elementAttributes->class;
+                }
+
+                $classMetadata->setClassDiscriminatorMapping(new ClassDiscriminatorMapping(
+                    (string) $xml->{'discriminator-map'}->attributes()->{'type-property'},
+                    $mapping,
+                    $xml->{'discriminator-map'}->attributes()->{'default-type'} ?? null
+                ));
+            }
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Return the names of the classes mapped in this file.
+     *
+     * @return string[]
+     */
+    public function getMappedClasses(): array
+    {
+        return array_keys($this->classes ??= $this->getClassesFromXml());
+    }
+
+    /**
+     * Parses an XML File.
+     *
+     * @throws MappingException
+     */
+    private function parseFile(string $file): \SimpleXMLElement
+    {
+        try {
+            $dom = XmlUtils::loadFile($file, __DIR__.'/schema/dic/serializer-mapping/serializer-mapping-1.0.xsd');
+        } catch (\Exception $e) {
+            throw new MappingException($e->getMessage(), $e->getCode(), $e);
+        }
+
+        return simplexml_import_dom($dom);
+    }
+
+    private function getClassesFromXml(): array
+    {
+        $xml = $this->parseFile($this->file);
+        $classes = [];
+
+        foreach ($xml->class as $class) {
+            $classes[(string) $class['name']] = $class;
+        }
+
+        return $classes;
+    }
+
+    private function parseContext(\SimpleXMLElement $nodes): array
+    {
+        $context = [];
+
+        foreach ($nodes as $node) {
+            if (\count($node) > 0) {
+                if (\count($node->entry) > 0) {
+                    $value = $this->parseContext($node->entry);
+                } else {
+                    $value = [];
+                }
+            } else {
+                $value = XmlUtils::phpize($node);
+            }
+
+            if (isset($node['name'])) {
+                $context[(string) $node['name']] = $value;
+            } else {
+                $context[] = $value;
+            }
+        }
+
+        return $context;
+    }
+}

vendor/symfony/serializer/Mapping/Loader/YamlFileLoader.php

@@ -0,0 +1,174 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Serializer\Mapping\Loader;
+
+use Symfony\Component\PropertyAccess\Exception\InvalidPropertyPathException;
+use Symfony\Component\PropertyAccess\PropertyPath;
+use Symfony\Component\Serializer\Exception\MappingException;
+use Symfony\Component\Serializer\Mapping\AttributeMetadata;
+use Symfony\Component\Serializer\Mapping\ClassDiscriminatorMapping;
+use Symfony\Component\Serializer\Mapping\ClassMetadataInterface;
+use Symfony\Component\Yaml\Parser;
+use Symfony\Component\Yaml\Yaml;
+
+/**
+ * YAML File Loader.
+ *
+ * @author Kévin Dunglas <dunglas@gmail.com>
+ */
+class YamlFileLoader extends FileLoader
+{
+    private ?Parser $yamlParser = null;
+
+    /**
+     * An array of YAML class descriptions.
+     */
+    private ?array $classes = null;
+
+    public function loadClassMetadata(ClassMetadataInterface $classMetadata): bool
+    {
+        if (!$this->classes ??= $this->getClassesFromYaml()) {
+            return false;
+        }
+
+        if (!isset($this->classes[$classMetadata->getName()])) {
+            return false;
+        }
+
+        $yaml = $this->classes[$classMetadata->getName()];
+
+        if (isset($yaml['attributes']) && \is_array($yaml['attributes'])) {
+            $attributesMetadata = $classMetadata->getAttributesMetadata();
+
+            foreach ($yaml['attributes'] as $attribute => $data) {
+                if (isset($attributesMetadata[$attribute])) {
+                    $attributeMetadata = $attributesMetadata[$attribute];
+                } else {
+                    $attributeMetadata = new AttributeMetadata($attribute);
+                    $classMetadata->addAttributeMetadata($attributeMetadata);
+                }
+
+                if (isset($data['groups'])) {
+                    if (!\is_array($data['groups'])) {
+                        throw new MappingException(\sprintf('The "groups" key must be an array of strings in "%s" for the attribute "%s" of the class "%s".', $this->file, $attribute, $classMetadata->getName()));
+                    }
+
+                    foreach ($data['groups'] as $group) {
+                        if (!\is_string($group)) {
+                            throw new MappingException(\sprintf('Group names must be strings in "%s" for the attribute "%s" of the class "%s".', $this->file, $attribute, $classMetadata->getName()));
+                        }
+
+                        $attributeMetadata->addGroup($group);
+                    }
+                }
+
+                if (isset($data['max_depth'])) {
+                    if (!\is_int($data['max_depth'])) {
+                        throw new MappingException(\sprintf('The "max_depth" value must be an integer in "%s" for the attribute "%s" of the class "%s".', $this->file, $attribute, $classMetadata->getName()));
+                    }
+
+                    $attributeMetadata->setMaxDepth($data['max_depth']);
+                }
+
+                if (isset($data['serialized_name'])) {
+                    if (!\is_string($data['serialized_name']) || '' === $data['serialized_name']) {
+                        throw new MappingException(\sprintf('The "serialized_name" value must be a non-empty string in "%s" for the attribute "%s" of the class "%s".', $this->file, $attribute, $classMetadata->getName()));
+                    }
+
+                    $attributeMetadata->setSerializedName($data['serialized_name']);
+                }
+
+                if (isset($data['serialized_path'])) {
+                    try {
+                        $attributeMetadata->setSerializedPath(new PropertyPath((string) $data['serialized_path']));
+                    } catch (InvalidPropertyPathException) {
+                        throw new MappingException(\sprintf('The "serialized_path" value must be a valid property path in "%s" for the attribute "%s" of the class "%s".', $this->file, $attribute, $classMetadata->getName()));
+                    }
+                }
+
+                if (isset($data['ignore'])) {
+                    if (!\is_bool($data['ignore'])) {
+                        throw new MappingException(\sprintf('The "ignore" value must be a boolean in "%s" for the attribute "%s" of the class "%s".', $this->file, $attribute, $classMetadata->getName()));
+                    }
+
+                    $attributeMetadata->setIgnore($data['ignore']);
+                }
+
+                foreach ($data['contexts'] ?? [] as $line) {
+                    $groups = $line['groups'] ?? [];
+
+                    if ($context = $line['context'] ?? false) {
+                        $attributeMetadata->setNormalizationContextForGroups($context, $groups);
+                        $attributeMetadata->setDenormalizationContextForGroups($context, $groups);
+                    }
+
+                    if ($context = $line['normalization_context'] ?? false) {
+                        $attributeMetadata->setNormalizationContextForGroups($context, $groups);
+                    }
+
+                    if ($context = $line['denormalization_context'] ?? false) {
+                        $attributeMetadata->setDenormalizationContextForGroups($context, $groups);
+                    }
+                }
+            }
+        }
+
+        if (isset($yaml['discriminator_map'])) {
+            if (!isset($yaml['discriminator_map']['type_property'])) {
+                throw new MappingException(\sprintf('The "type_property" key must be set for the discriminator map of the class "%s" in "%s".', $classMetadata->getName(), $this->file));
+            }
+
+            if (!isset($yaml['discriminator_map']['mapping'])) {
+                throw new MappingException(\sprintf('The "mapping" key must be set for the discriminator map of the class "%s" in "%s".', $classMetadata->getName(), $this->file));
+            }
+
+            $classMetadata->setClassDiscriminatorMapping(new ClassDiscriminatorMapping(
+                $yaml['discriminator_map']['type_property'],
+                $yaml['discriminator_map']['mapping'],
+                $yaml['discriminator_map']['default_type'] ?? null
+            ));
+        }
+
+        return true;
+    }
+
+    /**
+     * Return the names of the classes mapped in this file.
+     *
+     * @return string[]
+     */
+    public function getMappedClasses(): array
+    {
+        return array_keys($this->classes ??= $this->getClassesFromYaml());
+    }
+
+    private function getClassesFromYaml(): array
+    {
+        if (!stream_is_local($this->file)) {
+            throw new MappingException(\sprintf('This is not a local file "%s".', $this->file));
+        }
+
+        $this->yamlParser ??= new Parser();
+
+        $classes = $this->yamlParser->parseFile($this->file, Yaml::PARSE_CONSTANT);
+
+        if (!$classes) {
+            return [];
+        }
+
+        if (!\is_array($classes)) {
+            throw new MappingException(\sprintf('The file "%s" must contain a YAML array.', $this->file));
+        }
+
+        return $classes;
+    }
+}

vendor/symfony/serializer/Mapping/Loader/schema/dic/serializer-mapping/serializer-mapping-1.0.xsd

@@ -0,0 +1,116 @@
+<?xml version="1.0" ?>
+
+<xsd:schema xmlns="http://symfony.com/schema/dic/serializer-mapping"
+            xmlns:xsd="http://www.w3.org/2001/XMLSchema"
+            targetNamespace="http://symfony.com/schema/dic/serializer-mapping"
+            elementFormDefault="qualified">
+
+    <xsd:annotation>
+        <xsd:documentation><![CDATA[
+      Symfony Serializer Mapping Schema, version 1.0
+      Authors: Kévin Dunglas, Samuel Roze
+
+      A serializer mapping connects attributes with serialization groups.
+    ]]></xsd:documentation>
+    </xsd:annotation>
+
+    <xsd:element name="serializer" type="serializer" />
+
+    <xsd:complexType name="serializer">
+        <xsd:annotation>
+            <xsd:documentation><![CDATA[
+        The root element of the serializer mapping definition.
+      ]]></xsd:documentation>
+        </xsd:annotation>
+        <xsd:choice minOccurs="0" maxOccurs="unbounded">
+            <xsd:element name="class" type="class" />
+        </xsd:choice>
+    </xsd:complexType>
+
+    <xsd:complexType name="class">
+        <xsd:annotation>
+            <xsd:documentation><![CDATA[
+        Contains serialization groups for a single class.
+
+        Nested elements may be class property and/or getter definitions.
+      ]]></xsd:documentation>
+        </xsd:annotation>
+        <xsd:choice minOccurs="0" maxOccurs="unbounded">
+            <xsd:element name="attribute" type="attribute" minOccurs="0" maxOccurs="unbounded" />
+            <xsd:element name="discriminator-map" type="discriminator-map" />
+        </xsd:choice>
+        <xsd:attribute name="name" type="xsd:string" use="required" />
+    </xsd:complexType>
+
+    <xsd:complexType name="discriminator-map">
+        <xsd:choice minOccurs="0" maxOccurs="unbounded">
+            <xsd:element name="mapping" type="discriminator-map-mapping" maxOccurs="unbounded" />
+        </xsd:choice>
+        <xsd:attribute name="type-property" type="xsd:string" use="required" />
+        <xsd:attribute name="default-type" type="xsd:string" />
+    </xsd:complexType>
+
+    <xsd:complexType name="discriminator-map-mapping">
+        <xsd:attribute name="type" type="xsd:string" use="required" />
+        <xsd:attribute name="class" type="xsd:string" use="required" />
+    </xsd:complexType>
+
+    <xsd:complexType name="attribute">
+        <xsd:annotation>
+            <xsd:documentation><![CDATA[
+        Contains serialization groups and max depth for attributes. The name of the attribute should be given in the "name" option.
+      ]]></xsd:documentation>
+        </xsd:annotation>
+        <xsd:choice minOccurs="0" maxOccurs="unbounded">
+            <xsd:element name="group" type="xsd:string" maxOccurs="unbounded" />
+            <xsd:element name="context" type="context" maxOccurs="unbounded" />
+            <xsd:element name="normalization_context" type="context" maxOccurs="unbounded" />
+            <xsd:element name="denormalization_context" type="context" maxOccurs="unbounded" />
+        </xsd:choice>
+        <xsd:attribute name="name" type="xsd:string" use="required" />
+        <xsd:attribute name="max-depth">
+            <xsd:simpleType>
+                <xsd:restriction base="xsd:integer">
+                    <xsd:minInclusive value="0" />
+                </xsd:restriction>
+            </xsd:simpleType>
+        </xsd:attribute>
+        <xsd:attribute name="serialized-name">
+            <xsd:simpleType>
+                <xsd:restriction base="xsd:string">
+                    <xsd:minLength value="1" />
+                </xsd:restriction>
+            </xsd:simpleType>
+        </xsd:attribute>
+        <xsd:attribute name="serialized-path">
+            <xsd:simpleType>
+                <xsd:restriction base="xsd:string">
+                    <xsd:minLength value="1" />
+                </xsd:restriction>
+            </xsd:simpleType>
+        </xsd:attribute>
+        <xsd:attribute name="ignore" type="xsd:boolean" />
+    </xsd:complexType>
+
+    <xsd:complexType name="context">
+        <xsd:choice maxOccurs="unbounded">
+            <xsd:element name="group" type="xsd:string" minOccurs="0" maxOccurs="unbounded" />
+            <xsd:element name="entry" type="context-root-entry" maxOccurs="unbounded" />
+        </xsd:choice>
+    </xsd:complexType>
+
+    <xsd:complexType name="context-root-entry" mixed="true">
+        <xsd:sequence minOccurs="0">
+            <xsd:element name="entry" type="context-entry" maxOccurs="unbounded" />
+        </xsd:sequence>
+        <xsd:attribute type="xsd:string" name="name" use="required" />
+    </xsd:complexType>
+
+    <xsd:complexType name="context-entry" mixed="true">
+        <xsd:sequence minOccurs="0">
+            <xsd:element name="entry" type="context-entry" maxOccurs="unbounded" />
+        </xsd:sequence>
+        <xsd:attribute type="xsd:string" name="name" />
+    </xsd:complexType>
+
+</xsd:schema>