Issue #1483736 by stefan.r, bfcam, jrigby: field_attach_update deletes file fields (content & file) in entity regardless of if they are included in the entity object

Author: DavidRothstein

modules/file/file.field.inc

@@ -252,6 +252,12 @@ function file_field_insert($entity_type, $entity, $field, $instance, $langcode,
  * Checks for files that have been removed from the object.
  */
 function file_field_update($entity_type, $entity, $field, $instance, $langcode, &$items) {
+  // Check whether the field is defined on the object.
+  if (!isset($entity->{$field['field_name']})) {
+    // We cannot check for removed files if the field is not defined.
+    return;
+  }
+
   list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);
 
   // On new revisions, all files are considered to be a new usage and no

modules/file/tests/file.test

@@ -474,6 +474,15 @@ class FileFieldWidgetTestCase extends FileFieldTestCase {
       $node_file = (object) $node->{$field_name}[LANGUAGE_NONE][0];
       $this->assertFileExists($node_file, 'New file saved to disk on node creation.');
 
+      // Test that running field_attach_update() leaves the file intact.
+      $field = new stdClass();
+      $field->type = $type_name;
+      $field->nid = $nid;
+      field_attach_update('node', $field);
+      $node = node_load($nid);
+      $node_file = (object) $node->{$field_name}[LANGUAGE_NONE][0];
+      $this->assertFileExists($node_file, 'New file still saved to disk on field update.');
+
       // Ensure the file can be downloaded.
       $this->drupalGet(file_create_url($node_file->uri));
       $this->assertResponse(200, 'Confirmed that the generated URL is correct by downloading the shipped file.');