From mboxrd@z Thu Jan  1 00:00:00 1970
From: Junio C Hamano <junkio@cox.net>
Subject: Re: comparing file contents in is_exact_match?
Date: Wed, 05 Jul 2006 23:20:13 -0700
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References: <20060706055729.GA12512@admingilde.org>
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To: Martin Waitz <tali@admingilde.org>
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	of "Thu, 6 Jul 2006 07:57:29 +0200")
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Martin Waitz <tali@admingilde.org> writes:

> The reason for that is that is_exact_match (in diffcore-rename.c) maps
> both the source and destination file into memory and then compares them
> byte for byte.  This is a little bit too much for my little machine.
>
> When I remove the content comparation and only leave the sha1
> comparision, then my renames are correctly found in a second.  But
> unluckily, some other renames in the testcases are not correctly
> handled any more.
>
> So is there an easy solution?  Why is the content comparision in
> is_exact_match needed?

Because your working tree can be out of sync with respect to
what's in the index, in which case we cannot trust the sha1
while running diff-index (without --cached flag).

git-update-index --refresh before doing anything might help.