Merge branch '2.7' into 2.8

* 2.7:
  [Security\Http] detect bad redirect targets using backslashes
  [Form] Filter file uploads out of regular form types
  Fix CI
  minor #28258 [travis] fix composer.lock invalidation for deps=low (nicolas-grekas)
  [travis] fix composer.lock invalidation for PRs patching several components
  [travis] fix composer.lock invalidation for deps=low
  minor #28199 [travis][appveyor] use symfony/flex to accelerate builds (nicolas-grekas)
  [travis] ignore ordering when validating composer.lock files for deps=low
  minor #28146 [travis] cache composer.lock files for deps=low (nicolas-grekas)
  fix ci
  [travis] fix requiring mongodb/mongodb before composer up
  minor #28114 [travis] merge "same Symfony version" jobs in one (nicolas-grekas)
  [2.7] Make CI green
  updated VERSION for 2.7.49
  updated CHANGELOG for 2.7.49
  [HttpKernel] fix trusted headers management in HttpCache and InlineFragmentRenderer
  [HttpFoundation] Remove support for legacy and risky HTTP headers
  updated VERSION for 2.7.48
  update CONTRIBUTORS for 2.7.48
  updated CHANGELOG for 2.7.48

Author: nicolas-grekas

Extension/Core/Type/FileType.php

@@ -105,6 +105,7 @@ public function configureOptions(OptionsResolver $resolver)
             'data_class' => $dataClass,
             'empty_data' => $emptyData,
             'multiple' => false,
+            'allow_file_upload' => true,
         ));
     }
 

Extension/Core/Type/FormType.php

@@ -231,6 +231,7 @@ public function configureOptions(OptionsResolver $resolver)
             'attr' => $defaultAttr,
             'post_max_size_message' => 'The uploaded file was too large. Please try to upload a smaller file.',
             'upload_max_size_message' => $uploadMaxSizeMessage, // internal
+            'allow_file_upload' => false,
         ));
 
         $resolver->setNormalizer('attr', $attrNormalizer);

Form.php

@@ -537,6 +537,11 @@ public function submit($submittedData, $clearMissing = true)
             $submittedData = null;
         } elseif (is_scalar($submittedData)) {
             $submittedData = (string) $submittedData;
+        } elseif ($this->config->getOption('allow_file_upload')) {
+            // no-op
+        } elseif ($this->config->getRequestHandler()->isFileUpload($submittedData)) {
+            $submittedData = null;
+            $this->transformationFailure = new TransformationFailedException('Submitted data was expected to be text or number, file upload given.');
         }
 
         $dispatcher = $this->config->getEventDispatcher();
@@ -546,6 +551,10 @@ public function submit($submittedData, $clearMissing = true)
         $viewData = null;
 
         try {
+            if (null !== $this->transformationFailure) {
+                throw $this->transformationFailure;
+            }
+
             // Hook to change content of the data submitted by the browser
             if ($dispatcher->hasListeners(FormEvents::PRE_SUBMIT)) {
                 $event = new FormEvent($this, $submittedData);

Tests/CompoundFormTest.php

@@ -712,7 +712,7 @@ public function testSubmitPostOrPutRequestWithSingleChildForm($method)
             'REQUEST_METHOD' => $method,
         ));
 
-        $form = $this->getBuilder('image')
+        $form = $this->getBuilder('image', null, null, array('allow_file_upload' => true))
             ->setMethod($method)
             ->setRequestHandler(new HttpFoundationRequestHandler())
             ->getForm();
@@ -1088,6 +1088,21 @@ public function testDisabledButtonIsNotSubmitted()
         $this->assertFalse($submit->isSubmitted());
     }
 
+    public function testFileUpload()
+    {
+        $reqHandler = new HttpFoundationRequestHandler();
+        $this->form->add($this->getBuilder('foo')->setRequestHandler($reqHandler)->getForm());
+        $this->form->add($this->getBuilder('bar')->setRequestHandler($reqHandler)->getForm());
+
+        $this->form->submit(array(
+            'foo' => 'Foo',
+            'bar' => new UploadedFile(__FILE__, 'upload.png', 'image/png', 123, UPLOAD_ERR_OK),
+        ));
+
+        $this->assertSame('Submitted data was expected to be text or number, file upload given.', $this->form->get('bar')->getTransformationFailure()->getMessage());
+        $this->assertNull($this->form->get('bar')->getData());
+    }
+
     protected function createForm()
     {
         return $this->getBuilder()