Subject: Emacs unnecessarily leaves behind stale auto-save files after crash recovery

From: Kelly Dean <[email-masked]>
Date: Tue, 24 Apr 2012 12:30:42 -0700 (PDT)

I'm using Emacs on X on Debian 6 Stable. emacs-version says GNU Emacs 23.2.1 (i486-pc-linux-gnu, GTK+ Version 2.20.0) of 2010-12-11 on raven, modified by Debian.
Steps to reproduce the bug:
Open any writeable file in Emacs, modify it, and run do-auto-save.
kill -9 Emacs.
Restart Emacs, load the file, and run recover-this-file.
Save the file before the auto-save timeout.
Notice that the auto-save file remains, permanently, unless the buffer is later modified (which might not ever happen) and another auto-save operation overwrites the old auto-save file (which won't happen even if the buffer is modified, if the user saves the file before the auto-save timeout).
Desired behavior: delete the auto-save file (only if auto-save-visited-file-name is nil, of course) when the file is saved after being recovered, since the auto-save file no longer contains data which hasn't been saved to the primary file.