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

From: Junio C Hamano <gitster@pobox.com>
Date: May 7, 2014, 17:46 UTC
Message-ID: <xmqqha51bhxg.fsf@gitster.dls.corp.google.com>
In-Reply-To: <1399480977.11843.62.camel@stross>

David Turner <dturner@twopensource.com> writes:

Show 16 quoted lines

> On Wed, 2014-05-07 at 08:17 +0200, Johannes Sixt wrote:
>> >  		} else if (cache_name_pos(src, length) < 0)
>> >  			bad = _("not under version control");
>> > -		else if (lstat(dst, &st) == 0) {
>> > +		else if (lstat(dst, &dst_st) == 0 &&
>> > +			 (src_st.st_ino != dst_st.st_ino ||
>> > +			  (src_st.st_ino == 0 && strcasecmp(src, dst)))) {
>> 
>> Don't do that. st_ino is zero on Windows only because we do not spend time
>> to fill in the field. Don't use it as an indicator for a case-insensitive
>> file system; zero may be a valid inode number on other systems.
>
> I don't think it is a problem if zero is a valid inode.  The only thing
> that happens when there is a zero inode, is that we have to compare
> filenames.  The inode check is just an optimization to avoid doing a
> bunch of strcasecmp on systems that don't have to.

Am I correct to rephrase you that the code assumes that any filesystem that cannot give unique inum to different files will use 0 as the placeholder inum, so if src/dst share the same non-zero inum, it is guaranteed that is not a placeholder and we know they are different files without comparing the two paths?