read-file-name misbehavior

[Richard Y. Kim]

It looks like read-file-name is behaving as documented for both emacs
21 and emacs 22.  What I missed before is that the two documented
behavior is different for the two.  So the problem seems to be that
the change in behavior of read-file-name was not documented in NEWS
file.

Emacs 22 doc-string says:

    If the user exits with an empty minibuffer, this function returns
    an empty string.  (This can only happen if the user erased the
    pre-inserted contents or if `insert-default-directory' is nil.)

Emacs 21 doc-string says:

    Default name to DEFAULT-FILENAME if user enters a null string.

So emacs 22 returns "" if the user simply hits RETURN.
Emacs 21 returns default-name argument instead.

I guess I now need to make elisp code changes in igrep.el and all
other elips files to reflect the change in behavior of read-file-name.



Richard Y. Kim writes:
 > 
 > 
 > Evaluating following expression then hitting ENTER when prompted
 > results in incorrect value of "" rather than the expected value of
 > ".el".  For example, emacs version 21.4 returns "*.el", but
 > emacs 22 that I compiled using the latest code from cvs as of today
 > 2006/12/26 results in "".
 > 
 > (let ((insert-default-directory nil))
 >   (read-file-name "Enter [default: *.el]: " nil "*.el" nil nil))
 > 
 > I tracked this down after noticing that igrep.el package which I've
 > been using for many years on emacs 19, 20, and 21 suddenly broke when
 > I tried to use it on emacs 22.
 > 
 > 
 > 
 > 
 > In GNU Emacs 22.0.92.1 (i686-pc-linux-gnu, GTK+ Version 2.10.6)
 >  of 2006-12-26 on richard-laptop
 > X server distributor `The X.Org Foundation', version 11.0.70101000
 > configured using `configure  '--with-x-toolkit=gtk''
 > 
 > Important settings:
 >   value of $LC_ALL: nil
 >   value of $LC_COLLATE: nil
 >   value of $LC_CTYPE: nil
 >   value of $LC_MESSAGES: nil
 >   value of $LC_MONETARY: nil
 >   value of $LC_NUMERIC: nil
 >   value of $LC_TIME: nil
 >   value of $LANG: en_US.UTF-8
 >   locale-coding-system: utf-8
 >   default-enable-multibyte-characters: t
 > 
 > Major mode: Apropos
 > 
 > Minor modes in effect:
 >   display-time-mode: t
 >   tooltip-mode: t
 >   mouse-wheel-mode: t
 >   file-name-shadow-mode: t
 >   global-font-lock-mode: t
 >   font-lock-mode: t
 >   blink-cursor-mode: t
 >   unify-8859-on-encoding-mode: t
 >   utf-translate-cjk-mode: t
 >   auto-compression-mode: t
 >   line-number-mode: t
 > 
 > Recent input:
 > ESC C-b ESC w ESC > <return> <return> <return> C-y 
 > <return> C-x C-e <return> ESC x s u b m i <tab> C-a 
 > C-k b u g <tab> C-a C-k e m a <tab> <tab> C-a C-k b 
 > u g <tab> <tab> <backspace> <backspace> <backspace> 
 > s u b m <tab> <tab> h C-g C-h a b u g <return> C-x 
 > o C-n C-n C-n C-n C-n C-n C-n C-n C-n C-v C-s s u b 
 > m i t C-s C-e ESC x e d e b <tab> s u b m <tab> b u 
 > <tab> <backspace> <backspace> <tab> <tab> <return>
 > 
 > Recent messages:
 > Mark set [2 times]
 > ""
 > Mark set [3 times]
 > ""
 > Making completion list...
 > Quit [2 times]
 > Loading apropos...done
 > Type C-x 1 to remove help window.  
 > Mark saved where search started
 > Loading emacsbug...done
 > 
 > 
 >