GotoDiff throws and blocks Enter in add -p hunk edit file

[Narretz]

When you are manually editing a hunk with git add -p (from the command line), it will open a special diff file in the editor where you can edit the hunks.
Because Sublime Git binds GotoDiff to Enter in the context of markup.inserted/deleted.diff, you cannot use it in the context of manual hunk editing. The command also throws because it cannot extract the file name from the current diff file.
Is there a way to the default command for a key binding? Basically, we simply want to do what hitting "Enter" does in this cas