feat: add Additional Properties Extractor for dynamic object support

context.yaml

@@ -22,4 +22,3 @@ documents:
       - type: file
         sourcePaths:
           - src
-          - tests/Unit

src/Attribute/AdditionalProperties.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Spiral\JsonSchemaGenerator\Attribute;
+
+#[\Attribute(\Attribute::TARGET_PROPERTY)]
+final readonly class AdditionalProperties
+{
+    /**
+     * @param string $valueType The type of values for additional properties (e.g., 'string', 'int', 'number', 'boolean', 'mixed')
+     * @param class-string|null $valueClass Optional class reference for object-typed additional properties
+     */
+    public function __construct(
+        public string $valueType,
+        public ?string $valueClass = null,
+    ) {}
+}

src/Schema/Property.php

@@ -44,8 +44,12 @@ public function jsonSerialize(): array
 
         // Check if we have an array shape constraint that should override the type
         if (isset($this->validationRules['type']) && $this->validationRules['type'] === 'object') {
-            // Array shape overrides normal type processing
+            // Array shape or additional properties overrides normal type processing
             $property = \array_merge($property, $this->validationRules);
+
+            // Clean up internal metadata keys
+            unset($property['_additionalPropertiesClass']);
+
             return $property;
         }
 
@@ -61,7 +65,7 @@ public function jsonSerialize(): array
         // Apply validation rules from PHPDoc constraints (except type overrides)
         $filteredValidationRules = $this->validationRules;
         if (isset($filteredValidationRules['type'])) {
-            unset($filteredValidationRules['type'], $filteredValidationRules['properties'], $filteredValidationRules['required'], $filteredValidationRules['additionalProperties']);
+            unset($filteredValidationRules['type'], $filteredValidationRules['properties'], $filteredValidationRules['required'], $filteredValidationRules['additionalProperties'], $filteredValidationRules['_additionalPropertiesClass']);
         }
         $property = \array_merge($property, $filteredValidationRules);
 
@@ -84,6 +88,11 @@ public function getDependencies(): array
             }
         }
 
+        // Extract dependencies from additional properties references
+        if (isset($this->validationRules['_additionalPropertiesClass'])) {
+            $dependencies[] = $this->validationRules['_additionalPropertiesClass'];
+        }
+
         return $dependencies;
     }
 
@@ -107,7 +116,11 @@ protected function propertyTypeToDefinition(PropertyType $propertyType): array
                             }
                             $property['items']['anyOf'][] = $schemaType;
                         } else {
-                            $property['items']['anyOf'][] = ['$ref' => (new Reference($collectionType->type))->jsonSerialize()];
+                            $property['items']['anyOf'][] = [
+                                '$ref' => (new Reference(
+                                    $collectionType->type,
+                                ))->jsonSerialize(),
+                            ];
                         }
                     }
                 } elseif ($collectionTypeCount === 1) {

src/Validation/AdditionalPropertiesExtractor.php

@@ -0,0 +1,78 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Spiral\JsonSchemaGenerator\Validation;
+
+use Spiral\JsonSchemaGenerator\Attribute\AdditionalProperties;
+use Spiral\JsonSchemaGenerator\Parser\PropertyInterface;
+use Spiral\JsonSchemaGenerator\Schema\Reference;
+use Spiral\JsonSchemaGenerator\Schema\Type;
+
+final readonly class AdditionalPropertiesExtractor implements PropertyDataExtractorInterface
+{
+    public function extractValidationRules(PropertyInterface $property, Type $jsonSchemaType): array
+    {
+        $validationRules = [];
+
+        // Only process array types for additional properties
+        if ($jsonSchemaType !== Type::Array) {
+            return $validationRules;
+        }
+
+        $additionalProperties = $property->findAttribute(AdditionalProperties::class);
+        if (!$additionalProperties instanceof AdditionalProperties) {
+            return $validationRules;
+        }
+
+        // Override array type to object type for additional properties
+        $validationRules['type'] = 'object';
+
+        // Process the additional properties value type
+        $additionalPropertiesSchema = $this->processValueType(
+            $additionalProperties->valueType,
+            $additionalProperties->valueClass,
+        );
+
+        $validationRules['additionalProperties'] = $additionalPropertiesSchema;
+
+        // Store class dependencies for later extraction
+        if ($additionalProperties->valueType === 'object' && $additionalProperties->valueClass !== null) {
+            $validationRules['_additionalPropertiesClass'] = $additionalProperties->valueClass;
+        }
+
+        return $validationRules;
+    }
+
+    /**
+     * Process the value type and return appropriate JSON schema structure.
+     *
+     * @param class-string|null $valueClass
+     */
+    private function processValueType(string $valueType, ?string $valueClass): array|bool
+    {
+        return match ($valueType) {
+            'int', 'integer' => ['type' => 'integer'],
+            'number', 'float' => ['type' => 'number'],
+            'boolean', 'bool' => ['type' => 'boolean'],
+            'mixed' => true, // Allow any type
+            'object' => $this->processObjectType($valueClass),
+            default => ['type' => 'string'], // fallback to string
+        };
+    }
+
+    /**
+     * Process object type with class reference.
+     *
+     * @param class-string|null $valueClass
+     */
+    private function processObjectType(?string $valueClass): array
+    {
+        if ($valueClass === null) {
+            return ['type' => 'object'];
+        }
+
+        // Create reference to the class definition
+        return ['$ref' => (new Reference($valueClass))->jsonSerialize()];
+    }
+}

src/Validation/CompositePropertyDataExtractor.php

@@ -24,6 +24,7 @@ public static function createDefault(): self
         return new self([
             new PhpDocValidationConstraintExtractor(),
             new AttributeConstraintExtractor(),
+            new AdditionalPropertiesExtractor(), // Add the new extractor
         ]);
     }