updated for version 7.4.024 Problem: When root edits a file the undo file is owned by root while the edited file may be owned by another user, which is not allowed. (cac2s) Solution: Accept an undo file owned by the current user.

start:
test for empty string: ok
test for 1 char: ok
test for 3 chars: ok
test for contains meta char: ok
test for contains non-ascii char: ok