[PATCH 0/2] Re: ignorecase: Fix git mv on insensitive filesystems

From: dturner@twopensource.com <dturner@twopensource.com>
Date: May 8, 2014, 17:23 UTC
Message-ID: <1399569814-20644-1-git-send-email-dturner@twopensource.com>
In-Reply-To: <536B4680.1010806@web.de>

Torsten Bögershausen wrote:

Show 16 quoted lines

> On 05/08/2014 08:37 AM, Johannes Sixt wrote:
> > What if both inums are zero? Can this happen on any sane POSIX system? I
> > don't know, but my gut feeling is that inode zero is too special to be
> > allocated for files or directories.
> >
> > In that case, it is safe to assume that the st_ino field is just a
> > placeholder when it is zero, and we have to compare the file name. Then we
> > can either assume that this happens only for our emulation layer on MinGW
> > (and the comparison can be case-insensitive) or choose the comparison mode
> > based on core.ignorecase. This patch does the former, but I think we
> > should do the latter.
> Whatever we do, we should "protect" the strcasecmp() with ignore_case:
> 
> !ignore_case || strcasecmp(src, dst)
> 
> (And once that is done, you don't need to look at st_ino at all)

If both st_inos are zero on POSIX systems, there are two possibilities: the two files are case-clones, or the two files are hard-links of one another. Checking st_ino was just an optimization to avoid the slow string comparison. I hadn't considered the hard-link case important, but I guess it's better to be correct. So here's a patch without (as well as a cleaned-up version of the first patch, to keep the series together).