From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jonathan Nieder <jrnieder@gmail.com>
Subject: Re: [PATCH v2 0/3] rev-parse and "--"
Date: Mon, 9 Dec 2013 11:12:24 -0800
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Cc: Jeff King <peff@peff.net>, Duy Nguyen <pclouds@gmail.com>,
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To: Junio C Hamano <gitster@pobox.com>
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Junio C Hamano wrote:

>>                                      So maybe we are doing a favor by
>> calling out the problem; if they want a rev, they should be using
>> "--verify" (or "--").
>
> I tend to agree with the reasoning in the last sentence. Let's cook
> it for a while and see what happens.

Isn't this essentially breaking a contract that would have been relied
on by any script that used "git rev-parse HEAD~3..HEAD"?  Worse, it's
breaking that contract in a way that no one would notice until they
are asked to manipulate a worktree with a file named 'HEAD~3..HEAD'
--- in other words, the breakage it introduces is painfully subtle.

I agree that "git rev-parse HEAD" is better written as "git rev-parse
--verify HEAD" and hence not so much worth worrying about, but I don't
find it easy to believe that people should have anticipated this
change and added a trailing "--" to more complex rev-parse
expressions.

So to be clear, I think unless it is protected by a new option, this
is a bad idea.

Hope that helps,
Jonathan