execute treated any change in the group epoch as 'the group owns the step'. A command that edited outside its own group, or whose group rolled back before it edited, left that edit with no undo step or only part of it. Now only a group that was open before the command (or is still open after) owns the step; a command that opened and closed its own groups replaces their steps with one entry for the command.
prxnvt
f4e05534a3