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

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 13 Dec 2011 18:26:28 +0200
> From: jari <jari.aalto@cante.net>
> Cc: kbrown@cornell.edu, 10257@debbugs.gnu.org
> 
>      - The mapped drive can be written to without any extra 1:1 GUID,UID
>        configuration.
>      - Under Cygwin, should Emacs rely on unreliable[*] UID, GID?
>      - Is there need for this extra prompt? The protective
>        nature turned into nightmare.
> 
> Much better would be to give control back to the user:
> 
>   (setq write-file-interactive-confirmation-flag nil)
> 
> This doesn't affect Emacs's ability to signal an error on write
> failure.

Emacs assumes Posix-compliant APIs wrt UID/GID/EUID.  Platforms that
don't comply with the Posix semantics of these APIs should either
(a) become more compliant, or (b) modify the Emacs sources with
platform-specific code or #ifdef's to work around the lack of
compliance.  (Emacs maintainers generally prefer the former
possibility, for obvious reasons.)  All the other platforms do one
or the other; why should Cygwin be different? why should we change
long-standing Emacs code because one platform turns out to be non-
compliant, and the user refuses to work around the problem by
configuring his system in a slightly different way?