From: Junio C Hamano <gitster@pobox.com>
Date: Sun, 12 Jul 2020 20:52:17 GMT
Subject: Re: FETCH_HEAD files and mirrored repos
Message-ID: <xmqqr1tgpibi.fsf@gitster.c.googlers.com>
In-Reply-To: <20200712202502.x4p2c7rf6ctflt5g@chatter.i7.local>

Konstantin Ryabitsev <konstantin@linuxfoundation.org> writes:

> I also discovered that symlinking FETCH_HEAD to /dev/null works as well 
> and thus saves a few IO cycles.

We could teach "git fetch" a new "--write-fetch-head" option and
teach "git pull" to pass it when calling "git fetch".  It is very
plausible that some folks rely on "git fetch" to leave FETCH_HEAD
without being told, so the option must default to on for a few
development cycles before we flip the default to off, and for those
who want to live in the future a bit earlier, we can also introduce
fetch.writeFetchHEAD configuration variable that determines what
happens when "git fetch" is run without "--write-fetch-head" option
on the command line.  That way, you could drop 

	[fetch]
		writeFetchHEAD = 0

in say /etc/gitconfig or in ~/.gitconfig of the user that runs the
mirroring automation.