The default emacs switched from version 18 to 19

Friday, January 13, (perhaps a bad day to choose!), the default version of emacs was changed from version 18 to version 19. This was done without any public warning and the different version caught many people by surprise. We are, of course, sorry for any inconvenience. A version of emacs19 has been been available for testing (under that name) on the faculty machines for several months now.

Here are some of the differences which people have encountered:

RMAIL mode

Most of the complaints Friday were of the form "Mail is broken! I can't read my mail!" Since emacs19 starts up with a menu across the top, people were immediately aware that they were dealing with a new version.

There is one major gotcha which convinced people that emacs was broken:

     The "e" command under rmail was changed.

In emacs version 18, "e" means "rmail-expunge (erase all deleted messages in the file)." In emacs version 19, "e" means "rmail-edit-current-message (edit the contents of this message)." So people who tried to expunge deleted messages ended up editing the current message. Everything they typed was put into the message itself. Suddenly, all the regular mail commands didn't work! It was broken. (Though a message prints out when entering this mode how to exit it - via "^C ^C" - typing anything else causes this message to disappear.) The long list of options offered when asked about saving the RMAIL buffer was "garbage" and further evidence something strange was afoot.

Obviously, people should no longer use the "e" command to expunge deleted messages. "x" is now the command to use. "x" also had the same function under emacs 18.

Another complaint is "Mail is broken! I send mail and it doesn't arrive!" The mail is invariably sent to many recipients. The problem here is the way lines are automatically wrapped (broken up into reasonable lengths) in the headers of outgoing mail. If the headers look like this:

    To: adrian@remus.rutgers.edu, juo@paul.rutgers.edu,
    steiner@bakerst.rutgers.edu
    Subject: Problem with new mail
    --text follows this line--

there will be a problem. The RFC describing the format of mail dictates that continued lines (eg, the one with steiner on it above) should have white space before the first text. Since there is no white space, the mailer tries to figure out what kind of line it is. It fails, and assumes it and all lines following are part of the message text. So in the example above, the message would be delivered to adrian and juo and begin with the text

    steiner@bakerst.rutgers.edu
    Subject: Problem with new mail

To have the mail delivered correctly for now, you must add the white space yourself (as follows):

    To: adrian@remus.rutgers.edu, juo@paul.rutgers.edu,
        steiner@bakerst.rutgers.edu
    Subject: Problem with new mail
    --text follows this line--

I have reported this problem to the emacs maintainer. It is now fixed.

Another complaint: "When I read my mail, emacs puts me way back at some old message!" In this respect, emacs 19 is much smarter than emacs 18. It is putting you at the first unseen message. Under emacs 18, it was possible to skip unseen messages; not so under emacs 19. This should only be a problem to users who reply "n" when asked whether to save the RMAIL buffer on exiting. Unless you know what you are doing, it is usually a good idea to reply "y" to that question.

I have heard that there is some confusion using the normal rmail buffer movement commands after getting new mail following generating an RMAIL-summary buffer. Also, that buffer has a habit of reappearing after mail is sent. It's probably a good idea to delete the RMAIL-summary buffer before getting new mail.

"emacs generates the message `Maximum buffer size exceeded' when I try to read/save my mail." Due to the organization of internal memory structures, there is a maximum size that any buffer can be. If this happens to you when reading mail, there is a procedure you can follow to recover from this situation.

The only other difference likely to confuse emacs rmail users is the "r" command. Under 18, it was bound to "rmail-reply-just-sender (reply to the current message, just to the sender)." Giving a numeric argument to the function ("^U r" is a numerical argument of 4) says to include others in the reply. Under 19, "r" is by default bound to "rmail-reply (reply to the current message, including all other recipients)." Giving a numeric argument to the function says to ignore others.