From: Junio C Hamano <junkio@cox.net>
To: Sam Vilain <sam@vilain.net>
Cc: git@vger.kernel.org
Subject: Re: [wishlist] git branch -d -r remotename
Date: Sun, 18 Mar 2007 23:40:19 -0700 [thread overview]
Message-ID: <7v4pohka7g.fsf@assigned-by-dhcp.cox.net> (raw)
In-Reply-To: <7v8xdtkb7p.fsf@assigned-by-dhcp.cox.net> (Junio C. Hamano's message of "Sun, 18 Mar 2007 23:18:34 -0700")
Junio C Hamano <junkio@cox.net> writes:
> The standard way to check if commit A is included in (i.e. is an
> ancestor of) commit B, without traversing the ancestry chain of
> B all the way down to the root commit, is to run:
>
> git merge-base --all A B
>
> and see if A appears in its output (if so, then A is an ancestor
> of B, otherwise it is not). This is a pair-wise check, and for
> your purpose the check would become N*M operation (Yuck).
>
> The same check can be done in parallel with:
>
> git show-branch --independent A B C D...
>
> whose output would include A if the commit is not included in
> any of the other commits B C D... This parallel traversal has a
> limit --- you can only check 25 branches at a time.
Well, I was silly. If you want to see if A is an ancestor of
any of B C D..., the standard and most efficient way to do so is
with rev-list.
git rev-list A --not B C D...
will show _nothing_ only when A is an ancestor of one (or more)
of B C D..., so you invoke it and upon getting the first line of
output you declare A cannot be removed without reading the
remainder of the output.
show-branch --independent is an overkill for your purpose as it
does not treat A any more special from others (iow, it checks if
B is contained in A C D..., C is contained in A B D... all in
parallel), and you are not interested in finding out how remote
refs are related with each other.
next prev parent reply other threads:[~2007-03-19 6:40 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-18 9:36 [wishlist] git branch -d -r remotename Sam Vilain
2007-03-18 11:01 ` Sam Vilain
2007-03-18 11:01 ` Sam Vilain
2007-03-18 19:42 ` Junio C Hamano
2007-03-18 21:46 ` Sam Vilain
2007-03-19 6:18 ` Junio C Hamano
2007-03-19 6:40 ` Junio C Hamano [this message]
2007-03-19 23:37 ` (unknown) Sam Vilain
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