From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mike Hommey <mh@glandium.org>
Subject: Ambiguous sha-1 during a rebase
Date: Thu, 14 Apr 2016 07:29:19 +0900
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Hi,

Something interesting happened to me. I was in the middle of an
interactive rebase, and after a --continue, I got:

error: short SHA1 e34ff55 is ambiguous.
fatal: Needed a single revision
Invalid commit name: e34ff55

One thing that happened, is that, while running that interactive rebase,
I /also/ did a `git remote update` from an other shell, which, I guess,
happened to have imported another object that made e34ff55 ambiguous.

Should git-rebase use full sha-1s under the hood to avoid these type of
races?

Relatedly, having looked up the ambiguity, it turns out the other object
that fits the same short sha1 is a tree... maybe git should be able to
disambiguate in that case, since it was looking for a commit, and
there's only one commit with that short sha1?

Mike