From: Tejun Heo <tj@kernel.org>
To: Junio C Hamano <gitster@pobox.com>
Cc: git@vger.kernel.org, Jeff King <peff@peff.net>,
kernel-team@fb.com, Stefan Xenos <sxenos@google.com>
Subject: Re: [PATCHSET] git-reverse-trailer-xrefs: Reverse map cherry-picks and other cross-references
Date: Thu, 13 Dec 2018 08:15:46 -0800 [thread overview]
Message-ID: <20181213161546.GV2509588@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <xmqqftv2f05j.fsf@gitster-ct.c.googlers.com>
Hello, Junio.
On Thu, Dec 13, 2018 at 02:47:36PM +0900, Junio C Hamano wrote:
> Tejun Heo <tj@kernel.org> writes:
>
> > Hmmm... I see. I still have a bit of trouble seeing why doing it that
> > way is better tho. Wouldn't new-object-hook be simpler? They'll
> > achieve about the same thing but one would need to keep the states in
> > two places.
>
> The new-object-hook thing will not have keep the states. Whenever
> Git realizes that it created a new object, it must call that hook,
> and at that point in time, without keeping any state, it knows which
> objects are what it has just created. So "in two places" is not a
Yeap, that's what I was trying to say.
> problem at all. There is only one place (i.e. the place the sweeper
> would record what it just did to communicate with its future
> invocation).
>
> A new-object-hook that will always be called any time a new object
> enters the picture would be a nightmare to maintain up-to-date. One
But I didn't know this. I probably am too naive in thinking so but
it's a bit surprising that there's no single / few chokepoints for
repo updates that we can attach to.
> missed codepath and your coverage will have holes. Having a back-up
> mechanism to sweep for new objects will give you a better chance of
> staying correct as the system evolves, I'd think.
The duplicate state tracking still bothers me a bit (duplicate in the
sense that the end results are the same) especially as this would mean
any similar mechanism would need to track their own states too, but I
really don't have the full (not even close) picture here and it can
easily be me missing something.
Anyways, I'll wait for Stefan to chime in.
Thanks.
--
tejun
prev parent reply other threads:[~2018-12-13 16:15 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-11 23:49 [PATCHSET] git-reverse-trailer-xrefs: Reverse map cherry-picks and other cross-references Tejun Heo
2018-12-11 23:49 ` [PATCH 1/5] trailer: Implement a helper to reverse-map trailer xrefs Tejun Heo
2018-12-11 23:49 ` [PATCH 2/5] notes: Implement special handlings for refs/notes/xref- Tejun Heo
2018-12-11 23:49 ` [PATCH 3/5] notes: Implement git-reverse-trailer-xrefs Tejun Heo
2018-12-11 23:49 ` [PATCH 4/5] githooks: Add post-cherry-pick and post-fetch hooks Tejun Heo
2018-12-11 23:49 ` [PATCH 5/5] notes: Implement xref-cherry-picks hooks and tests Tejun Heo
2018-12-12 7:26 ` [PATCHSET] git-reverse-trailer-xrefs: Reverse map cherry-picks and other cross-references Junio C Hamano
2018-12-12 14:54 ` Tejun Heo
2018-12-13 3:01 ` Junio C Hamano
2018-12-13 3:09 ` Junio C Hamano
2018-12-13 3:46 ` Tejun Heo
2018-12-18 14:40 ` Stefan Xenos
2018-12-18 16:48 ` Stefan Xenos
2018-12-18 16:51 ` Tejun Heo
2018-12-13 3:40 ` Tejun Heo
2018-12-13 5:47 ` Junio C Hamano
2018-12-13 16:15 ` Tejun Heo [this message]
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