bug#22795: 25.0.91; Can't write read only file on w32

[Ota, Takaaki]

When a file is read only on w32 platform I used to be able to write a
file by toggling the buffer's read-only-mode state and answering yes
to this question "File memo is write-protected; try to save anyway?
(yes or no)" but now the writing fails by an error message "Opening
output file: Permission denied, c:/d/ota/memo" It still works on Linux
platform.  Is this a new feature/policy on w32 platform or a bug?  It
is certainly inconvenient.

-Tak




In GNU Emacs 25.0.91.2 (i686-pc-mingw32)
 of 2016-02-17 built on TAK-SVZ131190X
Windowing system distributor 'Microsoft Corp.', version 6.1.7601
Configured using:
 'configure --prefix=/c/emacs/emacs-25.0.91
 --enable-locallisppath=/c/emacs/site-lisp'

Configured features:
SOUND NOTIFY ACL TOOLKIT_SCROLL_BARS

Important settings:
  value of $LANG: ENU
  locale-coding-system: euc-jp-unix

Major mode: Summary

Minor modes in effect:
  auto-image-file-mode: t
  recentf-mode: t
  display-time-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  size-indication-mode: t
  column-number-mode: t

Recent messages:
Checking 70 files in c:/emacs/emacs-25.0.91/share/emacs/25.0.91/lisp/erc...
Checking 34 files in 
c:/emacs/emacs-25.0.91/share/emacs/25.0.91/lisp/emulation...
Checking 168 files in 
c:/emacs/emacs-25.0.91/share/emacs/25.0.91/lisp/emacs-lisp...
Checking 24 files in c:/emacs/emacs-25.0.91/share/emacs/25.0.91/lisp/cedet...
Checking 57 files in c:/emacs/emacs-25.0.91/share/emacs/25.0.91/lisp/calendar...
Checking 87 files in c:/emacs/emacs-25.0.91/share/emacs/25.0.91/lisp/calc...
Checking 122 files in 
c:/emacs/emacs-25.0.91/share/emacs/25.0.91/lisp/obsolete...
Checking for load-path shadows...done
scroll-one-line-down: Beginning of buffer [16 times]
Auto-saving...done
scroll-one-line-down: Beginning of buffer [12 times]

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message dired-x dired format-spec rfc822
mml mml-sec epg mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mail-utils dabbrev rect flyspell ispell sdicf-client stem sdicf sdic qp
browse-url character-fold misearch multi-isearch bookmark pp
network-stream nsm starttls tls gnutls mew-varsx ffap url-parse
auth-source cl-seq eieio eieio-core cl-macs gv gnus-util mm-util
help-fns mail-prsvr url-vars wwtime file-templates ruler-mode time-stamp
eudcb-ldap ldap password-cache eudc eudc-options-file cus-edit cus-start
cus-load eudc-vars edebug jka-compr compile image-file gud pcvs vc-cvs
pcvs-parse pcvs-info pcvs-defs easy-mmode pcvs-util ewoc recentf
tree-widget wid-edit byte-opt bytecomp byte-compile cl-extra help-mode
cl-loaddefs pcase cl-lib cconv mew-auth mew-config mew-imap2 mew-imap
mew-nntp2 mew-nntp mew-pop mew-smtp mew-ssl mew-ssh mew-net
mew-highlight mew-sort mew-fib mew-ext ange-ftp comint ansi-color ring
mew-refile mew-demo mew-attach mew-draft mew-message mew-thread
mew-virtual mew-summary4 mew-summary3 mew-summary2 mew-summary
mew-search mew-pick mew-passwd mew-scan mew-syntax mew-bq mew-smime
mew-pgp mew-header mew-exec mew-mark mew-mime mew-win32 mew-edit
mew-decode mew-encode mew-cache mew-minibuf mew-complete mew-addrbook
mew-local mew-vars3 mew-vars2 mew-vars mew-env mew-lang-jp mew-mule3
mew-mule mew-gemacs mew-key mew-func mew-blvs mew-const mew kkc
ja-dic-utl japan-util advice thingatpt time cal-china lunar solar
cal-dst cal-bahai cal-islam cal-hebrew holidays hol-loaddefs appt
diary-lib diary-loaddefs cal-menu calendar cal-loaddefs finder-inf
w3-autoloads package easymenu epg-config time-date mule-util tooltip
eldoc electric uniquify ediff-hook vc-hooks lisp-float-type mwheel
dos-w32 ls-lisp disp-table w32-win w32-vars 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 w32notify w32 multi-tty
make-network-process emacs)

Memory information:
((conses 8 421738 40180)
 (symbols 32 35267 0)
 (miscs 32 389 1024)
 (strings 16 84070 27755)
 (string-bytes 1 2070737)
 (vectors 8 31268)
 (vector-slots 4 1554396 32522)
 (floats 8 796 528)
 (intervals 28 7055 1406)
 (buffers 516 38))