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
