From: Jeff King <peff@peff.net>
To: Jacob Keller <jacob.keller@gmail.com>
Cc: Junio C Hamano <gitster@pobox.com>,
Jacob Keller <jacob.e.keller@intel.com>,
Git mailing list <git@vger.kernel.org>
Subject: Re: [RFC 3/3] refspec: add support for negative refspecs
Date: Tue, 18 Aug 2020 13:41:16 -0400 [thread overview]
Message-ID: <20200818174116.GA2473110@coredump.intra.peff.net> (raw)
In-Reply-To: <CA+P7+xpcm51cLPDDW+F1J-XZ2VvwNDWjnZqm54f3DKXxDfBF5Q@mail.gmail.com>
On Mon, Aug 17, 2020 at 05:04:00PM -0700, Jacob Keller wrote:
> > > + /* apply any negative refspecs now to prune the list of refs */
> > > + ref_map = apply_negative_refspecs(ref_map, rs);
> > > +
> > > ref_map = ref_remove_duplicates(ref_map);
> >
> > How was the ordering here decided? Should it result the same set if
> > negative ones are excluded after duplicates are removed?
>
> Good question. This was what was done in peff's original patch. I need
> to understand a bit more about what ref_remove_duplicates does to
> really figure this out.
The relevant commit is 2467a4fa03 (Remove duplicate ref matches in
fetch, 2007-10-08), I think. We may end up with multiple refspecs
requesting a particular ref. E.g.:
git fetch origin refs/heads/master refs/heads/*
I don't think the order should matter. If we apply negative refspecs
first, then we'd either remove both copies or leave both untouched (and
if the latter, then de-dup to a single). If we apply negative refspecs
after de-duping, then we'd either remove the single or leave it in
place. But the result is the same either way.
> > > @@ -1441,6 +1445,8 @@ int match_push_refs(struct ref *src, struct ref **dst,
> > > string_list_clear(&src_ref_index, 0);
> > > }
> > >
> > > + *dst = apply_negative_refspecs(*dst, rs);
> > > +
> >
> > The block of code whose tail is shown in the pre-context has
> > prepared "delete these refs because we no longer have them" to the
> > other side under MATCH_REFS_PRUNE but that was done based on the
> > *dst list before we applied the negative refspec. Is the ordering
> > of these two correct, or should we filter the dst list with negative
> > ones and use the resulting one in pruning operation?
>
> I think we need to swap the order here. I'll take a closer look.
Hmm. I think the behavior we'd want is something like:
# make sure the other side has three refs
git branch prune/one HEAD
git branch prune/two HEAD
git branch prune/three HEAD
git push dst.git refs/heads/prune/*
# now drop two of ours, which are eligible for pruning
git branch -d prune/one
git branch -d prune/two
# push with pruning, omitting "two"
git push --prune dst.git refs/heads/prune/* ^refs/heads/prune/two
# we should leave "two" but still deleted "one"
test_write_lines one three >expect
git -C dst.git for-each-ref --format='%(refname:lstrip=3)' refs/heads/prune/ >actual
test_cmp expect actual
I.e., the negative refspec shrinks the space we're considering pruning.
And we'd probably want a similar test for "fetch --prune".
I just tried that, though, and got an interesting result. The push
actually complains:
$ git push --prune dst.git refs/heads/prune/* ^refs/heads/prune/two
error: src refspec refs/heads/prune/two does not match any
error: failed to push some refs to 'dst.git'
For negative refspecs, would we want to loosen the "must-exist" check?
Or really, is this getting into the "are we negative on the src or dst"
thing you brought up earlier? Especially with --prune, what I really
want to say is "do not touch the remote refs/heads/two".
We can get work around it by using a wildcard:
$ git push --prune dst.git refs/heads/prune/* ^refs/heads/prune/two*
To dst.git
- [deleted] prune/one
So it works as I'd expect already with your patch. But I do wonder if
there are corner cases around the src/dst thing that might not behave
sensibly.
-Peff
next prev parent reply other threads:[~2020-08-18 17:41 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-15 0:25 [RFC 1/3] refspec: fix documentation referring to refspec_item Jacob Keller
2020-08-15 0:25 ` [RFC 2/3] refspec: make sure stack refspec_item variables are zeroed Jacob Keller
2020-08-17 16:33 ` Junio C Hamano
2020-08-17 16:49 ` Jacob Keller
2020-08-15 0:25 ` [RFC 3/3] refspec: add support for negative refspecs Jacob Keller
2020-08-17 18:02 ` Jacob Keller
2020-08-17 23:43 ` Junio C Hamano
2020-08-18 0:04 ` Jacob Keller
2020-08-18 17:41 ` Jeff King [this message]
2020-08-20 23:59 ` Jacob Keller
2020-08-21 2:33 ` Jeff King
2020-08-21 16:19 ` Junio C Hamano
2020-08-21 16:28 ` Jacob Keller
2020-08-21 17:16 ` Jacob Keller
2020-08-21 17:26 ` Jacob Keller
2020-08-21 18:21 ` Jacob Keller
2020-08-21 18:59 ` Jeff King
2020-08-17 16:18 ` [RFC 1/3] refspec: fix documentation referring to refspec_item Junio C Hamano
2020-08-21 21:17 ` Jacob Keller
2020-08-21 21:41 ` Junio C Hamano
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200818174116.GA2473110@coredump.intra.peff.net \
--to=peff@peff.net \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
--cc=jacob.e.keller@intel.com \
--cc=jacob.keller@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).