Re: should git maintenance prefetch be taught to honor remote.fetch refspec?

[Tom Saeger <tom.saeger@oracle.com>]

On Thu, Apr 01, 2021 at 03:07:37PM -0400, Derrick Stolee wrote:
> On 4/1/2021 2:49 PM, Tom Saeger wrote:
> > I've recently setup git maintenance and noticed prefetch task
> > fetches ALL remote refs (well not tags) and does not honor
> > remote fetch config settings.
> 
> This is intentional. The point is to get the latest objects
> without modifying any local copies of refs. You still need
> to run "git fetch" manually to update the refs, but that
> should be faster because you have most of the objects already
> in your copy of the repository.

I get all that.

In my particular use-case - I constrained the fetch refspec to purposely
limit the number of objects and remote refs only to those of interest.

"git fetch" won't ever use the other 120 refs that got pulled in by
prefetch.

If the configured remote fetch refspecs were honored,
prefetch would only update those objects/refs which `git fetch` would
have.

> 
> Here is the essential part of the documentation [1]:
> 
> 	The refmap is custom to avoid updating local or
> 	remote branches (those in refs/heads or refs/remotes).
> 	Instead, the remote refs are stored in
> 	refs/prefetch/<remote>/. Also, tags are not updated.
> 
> 	This is done to avoid disrupting the remote-tracking
> 	branches. The end users expect these refs to stay
> 	unmoved unless they initiate a fetch. With prefetch
> 	task, however, the objects necessary to complete a
> 	later real fetch would already be obtained, so the real
> 	fetch would go faster. In the ideal case, it will just
> 	become an update to a bunch of remote-tracking branches
> 	without any object transfer.
> 
> [1] https://git-scm.com/docs/git-maintenance#Documentation/git-maintenance.txt-prefetch
> 
> Thanks,
> -Stolee