Ensure content-type header is not empty before setting it

Author: specialtactics

src/Http/Response.php

@@ -142,7 +142,11 @@ public function morph($format = 'json')
 
         $defaultContentType = $this->headers->get('Content-Type');
 
-        $this->headers->set('Content-Type', $formatter->getContentType());
+        // If we have no content, we don't want to set this header, as it will be blank
+        $contentType = $formatter->getContentType();
+        if (!empty($contentType)) {
+            $this->headers->set('Content-Type', $formatter->getContentType());
+        }
 
         $this->fireMorphedEvent();
 
@@ -153,7 +157,9 @@ public function morph($format = 'json')
         } elseif (is_array($this->content) || $this->content instanceof ArrayObject || $this->content instanceof Arrayable) {
             $this->content = $formatter->formatArray($this->content);
         } else {
-            $this->headers->set('Content-Type', $defaultContentType);
+            if (!empty($defaultContentType)) {
+                $this->headers->set('Content-Type', $defaultContentType);
+            }
         }
 
         return $this;