bug #40699 [PropertyInfo] Make ReflectionExtractor correctly extract nullability (shiftby)

This PR was squashed before being merged into the 4.4 branch.

Discussion
----------

[PropertyInfo] Make ReflectionExtractor correctly extract nullability

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix #40659
| License       | MIT
| Doc PR        | no

When the property had a default value ReflectionExtractor was always returning isNullable: false. After PHP 7.4 we can get isNullable from the typehint.

Commits
-------

d5fce4c779 [PropertyInfo] Make ReflectionExtractor correctly extract nullability

src/Symfony/Component/PropertyInfo/Extractor/ReflectionExtractor.php

@@ -154,20 +154,8 @@ class ReflectionExtractor implements PropertyListExtractorInterface, PropertyTyp
             return $fromConstructor;
         }
 
-        if ($fromDefaultValue = $this->extractFromDefaultValue($class, $property)) {
-            return $fromDefaultValue;
-        }
-
-        if (\PHP_VERSION_ID >= 70400) {
-            try {
-                $reflectionProperty = new \ReflectionProperty($class, $property);
-                $type = $reflectionProperty->getType();
-                if (null !== $type && $types = $this->extractFromReflectionType($type, $reflectionProperty->getDeclaringClass())) {
-                    return $types;
-                }
-            } catch (\ReflectionException $e) {
-                // noop
-            }
+        if ($fromPropertyDeclaration = $this->extractFromPropertyDeclaration($class, $property)) {
+            return $fromPropertyDeclaration;
         }
 
         return null;
@@ -312,10 +300,19 @@ class ReflectionExtractor implements PropertyListExtractorInterface, PropertyTyp
         return null;
     }
 
-    private function extractFromDefaultValue(string $class, string $property): ?array
+    private function extractFromPropertyDeclaration(string $class, string $property): ?array
     {
         try {
             $reflectionClass = new \ReflectionClass($class);
+
+            if (\PHP_VERSION_ID >= 70400) {
+                $reflectionProperty = $reflectionClass->getProperty($property);
+                $reflectionPropertyType = $reflectionProperty->getType();
+
+                if (null !== $reflectionPropertyType && $types = $this->extractFromReflectionType($reflectionPropertyType, $reflectionProperty->getDeclaringClass())) {
+                    return $types;
+                }
+            }
         } catch (\ReflectionException $e) {
             return null;
         }
@@ -328,7 +325,7 @@ class ReflectionExtractor implements PropertyListExtractorInterface, PropertyTyp
 
         $type = \gettype($defaultValue);
 
-        return [new Type(static::MAP_TYPES[$type] ?? $type)];
+        return [new Type(static::MAP_TYPES[$type] ?? $type, $this->isNullableProperty($class, $property))];
     }
 
     private function extractFromReflectionType(\ReflectionType $reflectionType, \ReflectionClass $declaringClass): array
@@ -368,6 +365,25 @@ class ReflectionExtractor implements PropertyListExtractorInterface, PropertyTyp
         return $name;
     }
 
+    private function isNullableProperty(string $class, string $property): bool
+    {
+        try {
+            $reflectionProperty = new \ReflectionProperty($class, $property);
+
+            if (\PHP_VERSION_ID >= 70400) {
+                $reflectionPropertyType = $reflectionProperty->getType();
+
+                return null !== $reflectionPropertyType && $reflectionPropertyType->allowsNull();
+            }
+
+            return false;
+        } catch (\ReflectionException $e) {
+            // Return false if the property doesn't exist
+        }
+
+        return false;
+    }
+
     private function isAllowedProperty(string $class, string $property): bool
     {
         try {

src/Symfony/Component/PropertyInfo/Tests/Extractor/ReflectionExtractorTest.php

@@ -414,5 +414,6 @@ class ReflectionExtractorTest extends TestCase
         $this->assertEquals([new Type(Type::BUILTIN_TYPE_OBJECT, false, Dummy::class)], $this->extractor->getTypes(Php74Dummy::class, 'dummy'));
         $this->assertEquals([new Type(Type::BUILTIN_TYPE_BOOL, true)], $this->extractor->getTypes(Php74Dummy::class, 'nullableBoolProp'));
         $this->assertEquals([new Type(Type::BUILTIN_TYPE_ARRAY, false, null, true, new Type(Type::BUILTIN_TYPE_INT), new Type(Type::BUILTIN_TYPE_STRING))], $this->extractor->getTypes(Php74Dummy::class, 'stringCollection'));
+        $this->assertEquals([new Type(Type::BUILTIN_TYPE_INT, true)], $this->extractor->getTypes(Php74Dummy::class, 'nullableWithDefault'));
     }
 }

src/Symfony/Component/PropertyInfo/Tests/Fixtures/Php74Dummy.php

@@ -20,6 +20,7 @@ class Php74Dummy
     private ?bool $nullableBoolProp;
     /** @var string[] */
     private array $stringCollection;
+    private ?int $nullableWithDefault = 1;
 
     public function addStringCollection(string $string): void
     {