Check if file has been modified for each action provided.

When commiting multiple files we're now checking if any of those files
has been modified by another commit and we're rejecting the new commit
in this case.

1 files changed, 12 insertions, 0 deletions

diff --git a/app/services/files/multi_service.rb b/app/services/files/multi_service.rb
index bfacc462847..eb2773733b1 100644
--- a/app/services/files/multi_service.rb
+++ b/app/services/files/multi_service.rb
@@ -20,6 +20,7 @@ module Files
 
       params[:actions].each do |action|
         validate_action!(action)
+        validate_file_status(action)
       end
     end
 
@@ -28,5 +29,16 @@ module Files
         raise_error("Unknown action '#{action[:action]}'")
       end
     end
+
+    def validate_file_status(action)
+      return unless action[:last_commit_id]
+
+      current_commit = Gitlab::Git::Commit.last_for_path(
+        @start_project.repository, @start_branch, action[:file_path])
+
+      if current_commit.sha != action[:last_commit_id]
+        raise_error("The file has changed since you started editing it: #{action[:file_path]}")
+      end
+    end
   end
 end