Paul Mackerras wrote:
quoted text
> Is there a fast and easy way to find out which of a set of SHA1 ids
> refer to commits that (still) exist in a repository?
> 
> This is for use in gitk and there could be several ids, so I'd prefer
> to avoid a fork/exec per id.  I could do a git cat-file -t $id for
> each id, but that's a fork/exec per id.  git rev-parse doesn't check
> whether an id actually refers to an existing commit, so it isn't the
> answer.
> 

Assuming you have a completely random set of ids, I think the easiest
way to do it would be to extend git-cat-file to accept several ids
and then parse the error output from that.

quoted text
> What I want to be able to do is to cache the condensed topology
> information that gitk uses for working out next/previous tags.  But
> when I read in the cache I need to be able to know if the topology
> includes commits that used to exist but have now been removed.  Hence
> my question.
> 

I'm assuming you will still have to do git-rev-list to get the new commits
since the last known location of a branch head. If so, 
git rev-list <bogus-sha1>..<rewound-branch-tip> should be enough to
tell you you need to re-read that branch's entire history.

I just got up though, and since I don't drink coffee, waking up is a lengthy
process for me.

-- 
Andreas Ericsson                   andreas.ericsson@op5.se
OP5 AB                             www.op5.se
Tel: +46 8-230225                  Fax: +46 8-230231
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