Allow out of order FILES data.

Accept FILES data that has shuffled keys. Relying on key order in an
associative array is fragile. I've also added tests for some of the more
curious behaviors Validation::extension() has.

Refs #10267

src/Validation/Validation.php

@@ -691,7 +691,8 @@ class Validation
     public static function extension($check, $extensions = ['gif', 'jpeg', 'png', 'jpg'])
     {
         if (is_array($check)) {
-            return static::extension(array_shift($check), $extensions);
+            $check = isset($check['name']) ? $check['name'] : array_shift($check);
+            return static::extension($check, $extensions);
         }
         $extension = strtolower(pathinfo($check, PATHINFO_EXTENSION));
         foreach ($extensions as $value) {

tests/TestCase/Validation/ValidationTest.php

@@ -2292,6 +2292,8 @@ class ValidationTest extends TestCase
         $this->assertTrue(Validation::extension('extension.pdf', ['PDF']));
         $this->assertFalse(Validation::extension('extension.jpg', ['GIF']));
         $this->assertTrue(Validation::extension(['extension.JPG', 'extension.gif', 'extension.png']));
+        $this->assertFalse(Validation::extension(['extension.JPG', 'extension.gif', 'extension.png'], ['gif']));
+
         $this->assertTrue(Validation::extension(['file' => ['name' => 'file.jpg']]));
         $this->assertTrue(Validation::extension([
             'file1' => ['name' => 'file.jpg'],
@@ -2301,14 +2303,27 @@ class ValidationTest extends TestCase
         $this->assertFalse(Validation::extension(
             [
                 'file1' => ['name' => 'file.jpg'],
+                'file2' => ['name' => 'file.gif'],
+            ],
+            ['gif']
+        ), 'Only the first element should be checked');
+        $this->assertTrue(Validation::extension(
+            [
+                'file1' => ['name' => 'file.gif'],
                 'file2' => ['name' => 'file.jpg'],
-                'file3' => ['name' => 'file.jpg']
             ],
             ['gif']
-        ));
+        ), 'Only the first element should be checked');
+
+        $file = [
+            'tmp_name' => '/var/private/secret-file',
+            'name' => 'cats.gif'
+        ];
+        $this->assertTrue(Validation::extension($file), 'Uses filename if available.');
+        $this->assertTrue(Validation::extension(['file' => $file]), 'Walks through arrays.');
 
-        $this->assertFalse(Validation::extension(['noextension', 'extension.JPG', 'extension.gif', 'extension.png']));
-        $this->assertFalse(Validation::extension(['extension.pdf', 'extension.JPG', 'extension.gif', 'extension.png']));
+        $this->assertFalse(Validation::extension(['noextension', 'extension.JPG']));
+        $this->assertFalse(Validation::extension(['extension.pdf', 'extension.JPG']));
     }
 
     /**