Fix type and add changelog

Author: IonBazan

UPGRADE-3.0.md

@@ -23,6 +23,11 @@ generator to generate string UUIDs. For more efficient storage of UUIDs, use the
 `Doctrine\ODM\MongoDB\Types\BinaryUuidType` type in combination with the
 `Doctrine\ODM\MongoDB\Id\SymfonyUuidGenerator` generator.
 
+## Strong typing
+
+Native type hints have been introduced throughout the codebase. As a result, several
+methods signatures have changed, including but not limited to `Types` and `Mapping` namespaces.
+
 ## Metadata
 The `Doctrine\ODM\MongoDB\Mapping\ClassMetadata` class has been marked final and
 will no longer be extendable.
@@ -31,6 +36,8 @@ The `boolean`, `integer`, and `int_id` mapping types have been removed. Use the
 `bool`, `int`, and `int` types, respectively. These types behave exactly the
 same.
 
+The `Int64Type` no longer extends `IntType`.
+
 The `NOTIFY` change tracking policy has been removed, we suggest switching to
 `DEFERRED_EXPLICIT` instead. Consequentially `ClassMetadata::isChangeTrackingNotify` 
 and `ClassMetadata::CHANGETRACKING_NOTIFY` have been removed as well. `UnitOfWork`

src/Types/Int64Type.php

@@ -9,7 +9,7 @@
 /**
  * The Int64 type (long)
  */
-class Int64Type extends IntType
+class Int64Type extends Type implements Incrementable, Versionable
 {
     public function convertToDatabaseValue(mixed $value): ?Int64
     {
@@ -24,4 +24,19 @@ public function closureToMongo(): string
     {
         return '$return = new \MongoDB\BSON\Int64($value);';
     }
+
+    public function closureToPHP(): string
+    {
+        return '$return = (int) $value;';
+    }
+
+    public function diff(mixed $old, mixed $new): int
+    {
+        return (int) $new - $old;
+    }
+
+    public function getNextVersion(mixed $current): int
+    {
+        return max(1, (int) $current + 1);
+    }
 }

src/Types/IntType.php

@@ -11,12 +11,12 @@
  */
 class IntType extends Type implements Incrementable, Versionable
 {
-    public function convertToDatabaseValue(mixed $value): mixed
+    public function convertToDatabaseValue(mixed $value): ?int
     {
         return $value !== null ? (int) $value : null;
     }
 
-    public function convertToPHPValue(mixed $value): mixed
+    public function convertToPHPValue(mixed $value): ?int
     {
         return $value !== null ? (int) $value : null;
     }
@@ -31,9 +31,9 @@ public function closureToPHP(): string
         return '$return = (int) $value;';
     }
 
-    public function diff(mixed $old, mixed $new): mixed
+    public function diff(mixed $old, mixed $new): int
     {
-        return $new - $old;
+        return (int) $new - $old;
     }
 
     public function getNextVersion(mixed $current): int