From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ramkumar Ramachandra <artagnon@gmail.com>
Subject: Re: [PATCH] t4202 (log): add failing test for log with subtree
Date: Mon, 22 Apr 2013 18:24:29 +0530
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References: <1366632487-28153-1-git-send-email-artagnon@gmail.com>
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Cc: Matthieu Moy <Matthieu.Moy@grenoble-inp.fr>,
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	Avery Pennarun <apenwarr@gmail.com>,
	Junio C Hamano <gitster@pobox.com>
To: Thomas Rast <trast@inf.ethz.ch>
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Ramkumar Ramachandra wrote:
> Unless there is a commit with the following diff
> (with heuristically similar content), I don't see how --follow can
> work:
>
>     diff --git a/README b/README
>     deleted file mode 100644
>
>     diff --git a/subproject/README b/subproject/README
>     new file mode 100644

In other words, git diff-tree HEAD^2 HEAD is absolute nonsense in the
subtree case.

Let me outline how I think --follow works:
A 'git log --follow foo' executes a diff-tree with historical trees
until it finds one that removes (or adds, depending on which way you
look at it) the 'foo' entry.  It then inspects all the trees in the
corresponding commit for a blob that is heuristically similar to the
HEAD:foo blob, and follows it.

How can you logically extend this concept to handle my case?