From: Junio C Hamano <gitster@pobox.com>
To: Michael Haggerty <mhagger@alum.mit.edu>
Cc: git@vger.kernel.org
Subject: Re: Bug when git rev-list options "--first-parent" and "--ancestry-path" are used together?
Date: Thu, 23 May 2013 10:20:13 -0700 [thread overview]
Message-ID: <7vtxltfwaa.fsf@alter.siamese.dyndns.org> (raw)
In-Reply-To: <519DEA48.10108@alum.mit.edu> (Michael Haggerty's message of "Thu, 23 May 2013 12:07:04 +0200")
Michael Haggerty <mhagger@alum.mit.edu> writes:
> It seems to me that
>
> git rev-list --first-parent --ancestry-path A..B
>
> is well-defined and should list the commits in the intersection between
>
> git rev-list --first-parent A..B
>
> and
>
> git rev-list --ancestry-path A..B
>
> But in many cases the first command doesn't provide any output even
> though there are commits common to the output of the last two commands.
>
> For example, take as an example the DAG from test t6019:
>
> # D---E-------F
> # / \ \
> # B---C---G---H---I---J
> # / \
> # A-------K---------------L--M
>
> (The merges are always downwards; e.g., the first parent of commit L is
> K.) The command
>
> git rev-list --first-parent --ancestry-path D..J
>
> doesn't generate any output, whereas I would expect it to output "H I
> J".
As I do not see how "only show first-parent chains from near the tip
but stop immediately when the chain deviates from the ancestry path"
could be a sensible operation (in other words, I do not offhand
think of examples of what useful things you can do with that
information), I actually expect that "-f-p -a-p D..J" should error
out, instead of giving no output.
You are correct to point out that sometimes -f-p and -a-p _could_ be
compatible, e.g. "-f-p -a-p A..M", or "-f-p -a-p B..M". But I think
the only case that they are compatible is when "-f-p" output is a
strict subset of what "-a-p" without "-f-p" would give.
next prev parent reply other threads:[~2013-05-23 17:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-23 10:07 Bug when git rev-list options "--first-parent" and "--ancestry-path" are used together? Michael Haggerty
2013-05-23 17:20 ` Junio C Hamano [this message]
2013-05-25 18:40 ` Michael Haggerty
[not found] ` <519F0B2F.3090701@alum.mit.edu>
[not found] ` <7v4nds9rhh.fsf@alter.siamese.dyndns.org>
2013-05-25 19:54 ` Michael Haggerty
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