Add case for document upload where the document exists on disk but there is no database record - refs BT#7218

If upload is in overwrite mode (default), then overwrite the file and create the db record. This goes through the secure files filter first, so no worry there.

main/inc/lib/fileUpload.lib.php

@@ -256,6 +256,7 @@ function handle_uploaded_document(
 			$files_perm = api_get_permissions_for_new_files();
 
 			// What to do if the target file exists
+            error_log($what_if_file_exists);
 			switch ($what_if_file_exists) {
 				// Overwrite the file if it exists
 				case 'overwrite':
@@ -276,7 +277,18 @@ function handle_uploaded_document(
 
                                 // Redo visibility
                                 api_set_default_visibility(TOOL_DOCUMENT, $document_id);
-							}
+							} else {
+                                // There might be cases where the file exists on disk but there is no registration of that in the database
+                                // In this case, and if we are in overwrite mode, overwrite and create the db record
+                                $document_id = add_document($_course, $file_path, 'file', $file_size, $document_name, null, 0, true, null, $current_session_id);
+                                if ($document_id) {
+                                    // Put the document in item_property update
+                                    api_item_property_update($_course, TOOL_DOCUMENT, $document_id, 'DocumentAdded', $user_id, $to_group_id, $to_user_id, null, null, $current_session_id);
+
+                                    // Redo visibility
+                                    api_set_default_visibility(TOOL_DOCUMENT, $document_id);
+                                }
+                            }
 							// If the file is in a folder, we need to update all parent folders
 							item_property_update_on_folder($_course, $upload_path, $user_id);
 							// Display success message with extra info to user