fix: NullableTransformer should check if array key exists

.gitignore

@@ -2,3 +2,4 @@ vendor/
 composer.lock
 .php-cs-fixer.cache
 .phpunit.result.cache
+tests/cache/

src/Transformer/NullableTransformer.php

@@ -49,9 +49,21 @@ public function transform(Expr $input, Expr $target, PropertyMapping $propertyMa
             $itemStatements[] = new Stmt\Expression(new $assignClass($newOutput, $output));
         }
 
-        $statements[] = new Stmt\If_(new Expr\BinaryOp\NotIdentical(new Expr\ConstFetch(new Name('null')), $input), [
-            'stmts' => $itemStatements,
-        ]);
+        if ($input instanceof Expr\ArrayDimFetch) {
+            /*
+             * if `$input` is an array access, let's validate if the array key exists and is not null:
+             *
+             * if (isset($value['key'])) {
+             */
+            $statements[] = new Stmt\If_(new Expr\Isset_([$input]), ['stmts' => $itemStatements]);
+        } else {
+            /*
+             * otherwise, let's check the value is not null:
+             *
+             *  if ($input !== null) {
+             */
+            $statements[] = new Stmt\If_(new Expr\BinaryOp\NotIdentical(new Expr\ConstFetch(new Name('null')), $input), ['stmts' => $itemStatements]);
+        }
 
         return [$newOutput ?? $output, $statements];
     }

tests/AutoMapperTest.php

@@ -17,6 +17,7 @@
 use AutoMapper\Tests\Fixtures\AddressType;
 use AutoMapper\Tests\Fixtures\AddressWithEnum;
 use AutoMapper\Tests\Fixtures\ClassWithMapToContextAttribute;
+use AutoMapper\Tests\Fixtures\ClassWithNullablePropertyInConstructor;
 use AutoMapper\Tests\Fixtures\ClassWithPrivateProperty;
 use AutoMapper\Tests\Fixtures\Fish;
 use AutoMapper\Tests\Fixtures\ObjectWithDateTime;
@@ -1207,4 +1208,12 @@ public function testItCanDisablePrivatePropertiesMapping(): void
             $this->autoMapper->map(new ClassWithPrivateProperty('foo'), 'array')
         );
     }
+
+    public function testItCanMapFromArrayWithMissingNullableProperty(): void
+    {
+        self::assertEquals(
+            new ClassWithNullablePropertyInConstructor(foo: 1),
+            $this->autoMapper->map(['foo' => 1], ClassWithNullablePropertyInConstructor::class)
+        );
+    }
 }

tests/Fixtures/ClassWithNullablePropertyInConstructor.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace AutoMapper\Tests\Fixtures;
+
+readonly class ClassWithNullablePropertyInConstructor
+{
+    public function __construct(public int $foo, public int|null $bar = null)
+    {
+    }
+}