Re: [PATCH v3 0/3] Maintenance: adapt custom refspecs

From: Tom Saeger <tom.saeger@oracle.com>
Date: Apr 12, 2021, 16:48 UTC
Message-ID: <20210412164805.pxq7acln43gbggkl@dhcp-10-154-186-72.vpn.oracle.com>
In-Reply-To: <xmqqtuodiowj.fsf@gitster.g>

On Sat, Apr 10, 2021 at 06:35:40PM -0700, Junio C Hamano wrote:

Show 13 quoted lines

> "Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com> writes:
> 
> >  * The fix is almost completely rewritten as an update to 'git fetch'. See
> >    the new PATCH 2 for this update.
> 
> I do agree that it gives us the most flexibility there with nice
> encapsulation.  Nobody other than "git fetch" needs to know how it
> computes which remote refs are fetched given the real pathspec, and
> the only thing the caller with "--prefetch" is interested in is that
> the prefetch operation would not contaminate the remote-tracking
> refs.
> 
> Great idea.  I wish I were the one who thought of it first ;-)

Yes - this simplifies things greatly!

I do have one case that fails prefetch though. It's a case where all the remote's fetch configs are filtered out.

Example:

	[remote "pr-924"]
	    url = https://github.com/gitgitgadget/git
	    fetch = +refs/tags/pr-924/derrickstolee/maintenance/refspec-v3
	    skipfetchall = true
	    tagopt = --no-tags

In this case, running `git fetch pr-924` will fetch and update FETCH_HEAD, but running with maintenance prefetch task results in:

fatal: Couldn't find remote ref HEAD error: failed to prefetch remotes error: task 'prefetch' failed

I tracked this down a bit, but don't have a suggestion how to fix it.

builtin/fetch.c `get_ref_map` makes two calls to `filter_prefetch_refspec`, one for 'rs' and another for 'remote->fetch'.

`filter_prefetch_refspec` works and filters out the above fetch config. This correctly yields condition `rs->nr == 0` and `remote->fetch.nr == 0`

Later a call is made to `get_remote_ref(remote_refs, "HEAD")` which fails, leading to `fatal: Couldn't find remote ref HEAD`

Should this be expected, or should this now be special-cased for 'prefetch' somehow?

Regards,

--Tom