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From:   Junio C Hamano <gitster@pobox.com>
To:     Jeff King <peff@peff.net>
Cc:     Elijah Newren <newren@gmail.com>,
        Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>,
        Git Mailing List <git@vger.kernel.org>,
        Jonathan Nieder <jrnieder@gmail.com>,
        Sergey Organov <sorganov@gmail.com>
Subject: Re: [PATCH 5/7] tmp-objdir: new API for creating and removing
 primary object dirs
References: <pull.1080.git.git.1630376800.gitgitgadget@gmail.com>
        <67d3b2b09f9ddda616cdd0d1b12ab7afc73670ed.1630376800.git.gitgitgadget@gmail.com>
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        <YVVmssXlaFM6yD5W@coredump.intra.peff.net>
        <YVVrY0/kXfWHCWJ1@coredump.intra.peff.net>
Date:   Thu, 30 Sep 2021 13:06:41 -0700
In-Reply-To: <YVVrY0/kXfWHCWJ1@coredump.intra.peff.net> (Jeff King's message
        of "Thu, 30 Sep 2021 03:46:43 -0400")
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Jeff King <peff@peff.net> writes:

>   - is it possible for the merge code to ever write an object? I kind of
>     wonder if we'd ever do any cache-able transformations as part of a
>     content-level merge. I don't think we do now, though.

How is virtual merge base, result of an inner merge that recursively
merging two merge bases, fed to an outer merge as the ancestor?
Isn't it written as a tree object by the inner merge as a tree with
full of blob objects, so the outer merge does not have to treat a
merge base tree that is virtual any specially from a sole merge
base?