Re: [PATCH] remote: introduce config to set prefetch refs

From: Junio C Hamano <gitster@pobox.com>
Date: Sep 15, 2024, 16:12 UTC
Message-ID: <xmqqbk0osxp0.fsf@gitster.g>
In-Reply-To: <xmqqo74qro6f.fsf@gitster.g>

Junio C Hamano <gitster@pobox.com> writes:

Show 10 quoted lines

> Existing logic filteres them down to what matches configured
> remote.$name.fetch variable.  filter_prefetch_refspec() may further
> reduces the result by removing those whose .src side begins with
> "refs/tags/".
>
> Now you only look at what survived the above existing filtering, and
> further narrow it down by picking only ones that match the prefetch
> condition.  If the refspec that survived the filtering by the fetch
> refspec (and existing logic in filter_prefetch_refspec()) does not
> satisfy the prefetch condition, it won't be prefetched.

Sorry, but I misread the code.

By the time filter_prefetch_refspec() is called by get_ref_map(), this caller has "remote_refs" linked list that describes each ref it is going to fetch, so conceptually what is left for the prefetch logic to do is to selectively discard the elements on this list that are not worth asking the remote to send new object data for and use the remainder of the list in remote_refs list, and the logic to further limit this list with the prefetchref configuration would fit well here, but filter_prefetch_refspec() does not work on this list at all X-<. So the prefetchref limitation needs to come outside the function.