bug#10257: 23.3.1 Cygwin: network drives - file is write protected (false positive)

[Jari Aalto]

Package: emacs
Version: 23.3+1-4
Severity: normal

TEST CASE

    - OS: Windows 7 64 bit
    - Start Cygwin X server:
      XWin :0 -unixkill -multiwindow
    - Start Cygwin Emacs:
      DISPLAY=:0 emacs-X11 &
    - C-x C-f any network drive file

    Emacs marks the file as read-only (%%) and asks every time a question
    after pressing C-x C-s:

        File <name here> is write-protected; try to save anyway? (y or n)

PROBLEM

    The constant prompting "Y/N" makes writing to a network drive location
    exessively hard. It's nuissance to have to be able to confirm every
    save action.

    There doens't seem to be way to turn of this prompting.

SUGGESTION

    The logic of checking if file is write protedted or not does not seem
    to be reliable under Cygwin regarding network drives. The Permissions
    probably don't come through correctly for Emacs to examine them.

    A) Offer option to turn of confirmation
    B) or bypass write protection checks under Cygwin

TEST DATA

Here is an example under Cygwin Emacs:

    (file-attributes "/cygdrive/z/tmp/test-epackage.el")
    => (nil 1 4294967295.0 4294967295.0 (20194 11100) (20194 19792) (20194
    19792) 437 "-rwxr--r--" t (-1735557 1952988 . 8890) (30147 . 13405))

Under Cygwin Bash shell it looks like this:

    $ ls -la /cygdrive/z/tmp/test-epackage.el
    -rwxr--r-- 1 ???????? ???????? 437 Dec  9 20:02 
/cygdrive/z/tmp/test-epackage.el

Note: the uid and gid information is not available from this non-domain
network drive.