On Tue, Aug 18, 2020 at 10:41 AM Jeff King <peff@xxxxxxxx> wrote: > > 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. I'm not sure this is quite true in the case where destinations are supplied. Suppose this case: git fetch refs/heads/*:refs/remotes/origin/* refs/other/mybranch:refs/remotes/origin/mybranch This would ofcourse error out due to de-duping where we determine that both would fetch to the same place.. however if you also added a negative refspec: git fetch refs/heads/*:refs/remotes/origin/* refs/other/mybranch:refs/remotes/origin/mybranch ^refs/heads/mybranch then shouldn't this work? meaning we should de-dupe only after we apply negative refspecs in this case? > > > > > @@ -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". > Hmmm.. For regular push the negative refspec applies to the source. For prune though we only provide a destination.. > 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. > Right, there's some interesting questions here still. > -Peff I'll be adding this as a test! Thanks, Jake
