On 10/3/2018 9:36 AM, SZEDER Gábor wrote:

On Wed, Oct 03, 2018 at 03:23:57PM +0200, Ævar Arnfjörð Bjarmason wrote:

quoted

Don't have time to patch this now, but thought I'd send a note / RFC
about this.

Now that we have the commit graph it's nice to be able to set
e.g. core.commitGraph=true & gc.writeCommitGraph=true in ~/.gitconfig or
/etc/gitconfig to apply them to all repos.

But when I clone e.g. linux.git stuff like 'tag --contains' will be slow
until whenever my first "gc" kicks in, which may be quite some time if
I'm just using it passively.

So we should make "git gc --auto" be run on clone,

There is no garbage after 'git clone'...

And since there is no garbage, the gc will not write the commit-graph.

quoted

and change the
need_to_gc() / cmd_gc() behavior so that we detect that the
gc.writeCommitGraph=true setting is on, but we have no commit graph, and
then just generate that without doing a full repack.

Or just teach 'git clone' to run 'git commit-graph write ...'

I plan to add a 'fetch.writeCommitGraph' config setting. I was waiting 
until the file is incremental (on my to-do list soon), so the write is 
fast when only adding a few commits at a time. This would cover the 
clone case, too.

Thanks,
-Stolee