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Date: Sun, 1 Jun 2014 08:33:02 -0400
From: Aaron Schrab <aaron@schrab.com>
To: Daniel Shahaf <d.s@daniel.shahaf.name>
Cc: zsh-workers@zsh.org
Subject: Re:  vcs_info git: Fix stagedstr for empty repos
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At 02:26 +0000 01 Jun 2014, Daniel Shahaf <d.s@daniel.shahaf.name> wrote:
>'diff-index --cached --quiet $empty_tree' is an O(1) operation, but I 
>am not sure whether it is forwards compatible with future versions of 
>Git, i.e., whether it's a hack that happens to work or a legitimate use 
>of git's API.

git itself does that comparison in several places, including in the 
sample pre-commit hook that is shipped with it.  So I'd say that that 
behavior is highly unlikely to change.  Many of those places, including 
that sample hook actually hard-code the sha1 for the empty tree as 
4b825dc642cb6eb9a060e54bf8d69288fbee4904.