Path: utzoo!utgpu!watmath!uunet!tut.cis.ohio-state.edu!UUNET.UU.NET!talos!kjones
From: talos!kjones@UUNET.UU.NET (Kyle Jones)
Newsgroups: gnu.emacs.bug
Subject: Re: (supposed) Trouble with auto-fill
Summary: This is a bug.
Message-ID: <8812211624.AA03910@uunet.UU.NET>
Date: 21 Dec 88 14:32:22 GMT
References: <3357@mipos3.intel.com>
Sender: daemon@tut.cis.ohio-state.edu
Distribution: gnu
Organization: GNUs Not Usenet
Lines: 75

woodstock (Nate Hess) writes:
>What I'm curious about is why this behaviour was changed in the first
>place [...]

The RET/auto-fill bug was introduced by a change in the file
src/cmds.c between versions 18.51 and 18.52 .  Thanks go to Hal
Peterson of Cray Research for posting a fix for this (well over a
month ago); his article appears below.  Hal mentions that the problem
is exhibited on various Sun boxes, but the fix applies to all 18.52
installations.

There is no question that the offending code is incorrect.  The line
that causes the bug:

	SelfInsert ('\n', XFASTINT (arg1) > 1);

uses XFASTINT on a variable that could very well be a symbol, or a list.

kyle jones   <kjones@talos.UUCP>   ...!uunet!talos!kjones
-------
Article 271 of gnu.emacs.bug:
Path: talos!uunet!tut.cis.ohio-state.edu!earth.cray.com!hrp
From: hrp@earth.cray.com (Hal Peterson)
Newsgroups: gnu.emacs.bug
Subject: auto fill and newline in 18.52
Message-ID: <8811141801.AA29069@earth.cray.com>
Date: 14 Nov 88 18:01:39 GMT
Sender: daemon@tut.cis.ohio-state.edu
Distribution: gnu
Organization: GNUs Not Usenet
Lines: 43

newline no longer causes an auto-fill in GNU Emacs version 18.52
running on a Sun-3/50 or Sun-3/280 with SunOS 3.5.  Repeat by:

C-x b b u g RET					; get a new buffer
M-x t e x t - m o d e RET			; put it into a known mode
C-u M-x a u t o - f i l l RET			; turn on auto-fill
M-x s e t - v a r RET f i l l - c RET 7 0 RET	; set the fill column
M-4 M-0 x SPC M-4 M-0 x				; create text that should fill
RET						; demonstrate the bug

That last RET should cause the line to break after the first string of
'?x characters, but it does not.

The problem appears to be a misnamed variable reference in Fnewline in
cmds.c.  "arg1" is the raw prefix argument to newline, and arg is the
numeric interpretation of that argument.  The call to SelfInsert uses
arg1 but should use arg.  Following is a diff (which I have installed
on our system and which appears to fix the problem).

				Hal
--
Hal Peterson / Cray Research / 1440 Northland Dr. / Mendota Hts, MN  55120
hrp@cray.com			bungia!cray!hrp		    (612) 681-3145
============================================================
*** cmds.c-orig	Tue Jul 19 18:43:25 1988
--- cmds.c	Sun Nov 13 15:19:31 1988
***************
*** 237,243 ****
        if (flag)
  	InsCStr (&c1, 1);
        else
! 	SelfInsert ('\n', XFASTINT (arg1) > 1);
        XFASTINT (arg)--;		/* Ok since old and new vals both nonneg */
      }
  
--- 237,243 ----
        if (flag)
  	InsCStr (&c1, 1);
        else
! 	SelfInsert ('\n', XFASTINT (arg) > 1);
        XFASTINT (arg)--;		/* Ok since old and new vals both nonneg */
      }