bug#28513: 25.1; ido insists on guessing the wrong directory

[Guillaume Salagnac]

I want to reproduce the usual "save as..." feature that all GUI applications 
offer. But I fail to do so using ido-mode and I suspect a bug. Steps to 
reproduce are described below.

emacs -Q
M-x ido-mode
... I type stuff in the scratch buffer ...
C-x C-w
    (this brings the ido-write-file dialog in the minibuffer. the blue
     prompt is ~/ and all the subdirs are listed in red. fine so far)
... I type a new filename and then hit RETURN
    (this brings a [Confirm] notification in the minibuffer, so I have to hit
     RETURN once more to get the "Wrote /home/user/filename" message)
... I type some more stuff in the (now named) buffer ...
C-x C-w
(this brings the ido-write-file dialog once more, with the same
subdirectories in red)
... I type "k" then RETURN
(the blue prompt now says "Write file: ~/Desktop/" )
C-f
(the completions in red disappear ; the "~/Desktop" part of the prompt
becomes black and I can edit the path to my liking. but I don't)
RETURN

expected behaviour: emacs may or may not ask for a confirmation here, but 
eventually it should save my buffer as ~/Desktop/filename (as is the case with 
M-x write-file)

actual behaviour: emacs decides that I actually didn't want to change 
directories and says: File '~/filename' exists; overwrite ? I can choose either 
"cancel" or "confirm" but neither lead to the correct result.


Is this indeed a bug, or am I missing something obvious ?


In GNU Emacs 25.1.1 (x86_64-apple-darwin15.6.0, NS appkit-1404.47 Version 
10.11.6 (Build 15G1217))
of 2017-02-18 built on elcapitan.internal.macports.net
Windowing system distributor 'Apple', version 10.3.1404
Configured using:
'configure --prefix=/opt/local --without-ns --without-dbus
--without-gconf --without-libotf --without-m17n-flt --without-gpm
--without-gnutls --with-xml2 --with-modules --infodir
/opt/local/share/info/emacs --with-ns CC=/usr/bin/clang 'CFLAGS=-pipe
-Os -arch x86_64' 'LDFLAGS=-L/opt/local/lib
-Wl,-headerpad_max_install_names -Wl,-no_pie -arch x86_64'
CPPFLAGS=-I/opt/local/include'

Configured features:
NOTIFY ACL LIBXML2 ZLIB TOOLKIT_SCROLL_BARS NS MODULES

Important settings:
  value of $LC_CTYPE: en_US.UTF-8
  value of $LANG: C
  locale-coding-system: utf-8-unix

Major mode: Fundamental

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
Saving file /Users/gsalagnac/bla...
Wrote /Users/gsalagnac/bla
Mark set
next-line: End of buffer [3 times]
Mark set
next-line: End of buffer
Saving file /Users/gsalagnac/new-file...
Wrote /Users/gsalagnac/new-file
File ‘~/new-file’ exists; overwrite? (y or n) n
user-error: Canceled

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message dired format-spec rfc822 mml
mml-sec password-cache epg epg-config gnus-util mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util help-fns mail-prsvr mail-utils ido
seq byte-opt gv bytecomp byte-compile cl-extra help-mode easymenu cconv
cl-loaddefs pcase cl-lib time-date mule-util tooltip eldoc electric
uniquify ediff-hook vc-hooks lisp-float-type mwheel ns-win ucs-normalize
term/common-win tool-bar dnd fontset image regexp-opt fringe
tabulated-list newcomment elisp-mode lisp-mode prog-mode register page
menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock
syntax facemenu font-core frame cl-generic cham georgian utf-8-lang
misc-lang vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms
cp51932 hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese charscript case-table epa-hook jka-cmpr-hook help
simple abbrev minibuffer cl-preloaded nadvice loaddefs button faces
cus-face macroexp files text-properties overlay sha1 md5 base64 format
env code-pages mule custom widget hashtable-print-readable backquote
kqueue cocoa ns multi-tty make-network-process emacs)

Memory information:
((conses 16 207881 7570)
(symbols 48 20460 0)
(miscs 40 66 194)
(strings 32 19472 6289)
(string-bytes 1 589390)
(vectors 16 34429)
(vector-slots 8 666731 6726)
(floats 8 186 153)
(intervals 56 284 16)
(buffers 976 20))