From: Junio C Hamano <gitster@pobox.com>
Date: Fri, 22 Jun 2018 18:31:24 GMT
Subject: Re: [PATCH 09/23] midx: write pack names in chunk
Message-ID: <xmqqzhzmptab.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <08667213-02fa-6104-d8de-20ee92b6bdce@gmail.com>

Derrick Stolee <stolee@gmail.com> writes:

> The index extension documentation doesn't appear to be clear about
> which extensions are optional or required, but it seems the
> split-index is the only "required" one and uses lowercase for its
> extension id.

read-cache.c::

    /* Index extensions.
     *
     * The first letter should be 'A'..'Z' for extensions that are not
     * necessary for a correct operation (i.e. optimization data).
     * When new extensions are added that _needs_ to be understood in
     * order to correctly interpret the index file, pick character that
     * is outside the range, to cause the reader to abort.
     */