GNU bug report logs - #25814
Windows same_file macro is not reliable

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From: Eric Blake <eblake <at> redhat.com>
To: Kees Dekker <Kees.Dekker <at> infor.com>, 25814 <at> debbugs.gnu.org
Subject: bug#25814: [bug-diffutils] bug#25814: Windows same_file macro is not reliable
Date: Mon, 20 Feb 2017 10:53:51 -0600

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On 02/20/2017 10:01 AM, Kees Dekker wrote:
> Hi,
> 
> On file systems that do not support inodes (e.g. NTFS,

NTFS supports inodes; Cygwin uses them.  Just because Window's native
stat() is broken does not mean NTFS is broken.

> because not everything is POSIX), the same_file() macro (in system.h) is incorrect as st_ino (and probably st_dev) are meaningless.

Rather, instead of ignoring inode, it would be nicer (but indeed a more
complex task) to have gnulib work around window's broken stat() to
provide a version that works instead.  It only matters for file systems
that support hard links (like NTFS); on file systems like FAT that lack
hard links, hard-coding that inodes don't work is okay, but on NTFS
where hard-links are supported, treating same_file() as always returning
0 gives wrong results.

At any rate, this is an issue that needs to be resolved in gnulib, as
more than just diffutils is affected by it.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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