Prevent possible warnings on unset variables (#542)

Co-authored-by: Roy <rdmartines@vcn.nl>

Author: sudo-plz

src/ServerRequest.php

@@ -144,10 +144,10 @@ private static function normalizeNestedFileSpec(array $files = []): array
         foreach (array_keys($files['tmp_name']) as $key) {
             $spec = [
                 'tmp_name' => $files['tmp_name'][$key],
-                'size'     => $files['size'][$key],
-                'error'    => $files['error'][$key],
-                'name'     => $files['name'][$key],
-                'type'     => $files['type'][$key],
+                'size'     => $files['size'][$key] ?? null,
+                'error'    => $files['error'][$key] ?? null,
+                'name'     => $files['name'][$key] ?? null,
+                'type'     => $files['type'][$key] ?? null,
             ];
             $normalizedFiles[$key] = self::createUploadedFileFromSpec($spec);
         }

tests/ServerRequestTest.php

@@ -163,6 +163,7 @@ public function dataNormalizeFiles(): iterable
                         'tmp_name' => [
                             0 => '/tmp/php/hp9hskjhf',
                             1 => '/tmp/php/php1h4j1o',
+                            2 => '/tmp/php/w0ensl4ar',
                         ],
                         'error' => [
                             0 => '0',
@@ -173,6 +174,11 @@ public function dataNormalizeFiles(): iterable
                             1 => '7349',
                         ],
                     ],
+                    'minimum_data' => [
+                        'tmp_name' => [
+                            0 => '/tmp/php/hp9hskjhf',
+                        ],
+                    ],
                     'nested' => [
                         'name' => [
                             'other' => 'Flag.txt',
@@ -227,6 +233,18 @@ public function dataNormalizeFiles(): iterable
                             'Image.png',
                             'image/png'
                         ),
+                        2 => new UploadedFile(
+                            '/tmp/php/w0ensl4ar',
+                            null,
+                            UPLOAD_ERR_OK
+                        ),
+                    ],
+                    'minimum_data' => [
+                        0 => new UploadedFile(
+                            '/tmp/php/hp9hskjhf',
+                            0,
+                            UPLOAD_ERR_OK
+                        ),
                     ],
                     'nested' => [
                         'other' => new UploadedFile(