Re: Plumbing version of 'git branch --contains' ?

Jeff King [off-list ref] writes:

On Wed, Oct 22, 2014 at 08:19:07PM +0000, Crabtree, Andrew wrote:

quoted

I need to get a list of refs that can reach a certain SHA in in a script.

git branch --contains SHA 

would be great (runs in ~2 seconds), but not my preferred option for scripting.

I tried
 
for br in $(git for-each-ref --format='%(refname:short)' refs/heads/)
do
    git merge-base --is-ancestor $1 ${br}
    if [ $? -eq 0 ]
    then
            echo "${br}"
    fi
done

Which gives me perfect output, but takes 82 seconds to run in my environment.

Right. There's some setup work that happens in `git branch --contains`
that we end up repeating.

quoted

Is there an alternative I'm missing to give me the run time
performance of 'git branch --contains' but with stable output suitable
for parsing?

Sadly, no, there isn't currently. The right tool would be `git
for-each-ref --contains`, but it doesn't exist yet. I was working
towards it, but got stopped on factoring out a `--contains` traversal
suitable for both `git tag` and `git branch` (they currently are
different and make performance tradeoffs based on the expected depth of
the merge bases, which is usually different between tags and
branches)[1].  That's work I'd love to resume, but I haven't gotten
around to it yet.

-Peff

[1] http://thread.gmane.org/gmane.comp.version-control.git/252472

Thanks for status update.  I was wondering if I should start looking
into it myself.