Taylor Blau <me@xxxxxxxxxxxx> 于2025年2月28日周五 08:12写道： > > (There's a parallel discussion going on in [1], so it isn't entirely > clear which thread to respond to. Since it seems a little premature to > comment on the patch itself, I'll respond here.) So sorry, I used another email address to submit the patch, it is indeed a bit early > On Thu, Feb 27, 2025 at 03:24:07PM +0800, SURA wrote: > > I found that packed refs are excluded by the transfer.hideRefs front > > match, while loose refs use full match (when transfer.hideRefs ends > > with '/', it is prefix match, which is normal) > > > > When the server uses git, after setting transfer.hideRefs, the > > references that the client can see before and after server repo gc are > > different > > It's true that the low-level loose references iterator does not know how > to handle excluded patterns, and that is by design. In the packed-refs > case, we can skip over whole sections of the packed-refs file according > to which patterns are excluded. > > But in the loose references case, we haven't implemented anything like > that to skip over, e.g. enumerating the contents of > "$GIT_DIR/refs/heads/foo" when "refs/heads/foo/" is excluded. (As an > aside, this is something that we could do, it just hasn't been > implemented yet). > > So in practice today the only way to exclude loose references according > to some set of exclusion patterns would be to filter them out as we > iterate over them. But that is the caller's responsibility, as we see in > a handful of comments in refs.h which say "any pattern in > 'exclude_patterns' [is] omitted on a best-effort basis". > > So upload-pack / etc. will see all loose references, and it filters out > the ones which it's supposed to hide via: > > upload_pack() -> for_each_namespaced_ref_1() -> send_ref() -> > write_v0_ref() -> mark_our_ref() -> ref_is_hidden() > > , where mark_our_ref() tosses out references that the low-level refs > iterator gave back to it which match one of the excluded patterns. > > And there we have ref_is_hidden() doing the following for each hidden > pattern: > > if (subject && > skip_prefix(subject, match, &p) && > (!*p || *p == '/')) > return !neg; > > So if the reference either matches the pattern exactly, or matches up to > a '/', then it is hidden and thus not advertised. > > I have to imagine I'm missing something, but perhaps it would be useful > if you could provide a reproduction script that demonstrates what you're > seeing. > > > It seems that 59c35fa accidentally damaged upload-pack when optimizing > > git for-each-ref > > No. 59c35fac54 (refs/packed-backend.c: implement jump lists to avoid > excluded pattern(s), 2023-07-10) predates any behavior changes in > upload-pack, which were introduced later on in 18b6b1b5c5 > (upload-pack.c: avoid enumerating hidden refs where possible, > 2023-07-10). > > Thanks, > Taylor > > [1]: https://lore.kernel.org/git/MA0P287MB06412DF70BCDA0D99641129FE4CD2@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/T/#t I shouldn't have mentioned the '/' suffix, it's confusing My previous description was not clear enough. The early hiding according to exclude_patterns in packed_ref_iterator_begin seems to be designed for git for-each-ref's exclude. It is different from the ref_hidden matching rule used by upload-pack. I provide a reproducible step to make it clear ------ # create git repo $ mkdir sura-repo && cd sura-repo $ git init # create one commit $ echo "hello" > file-001 $ git add . && git commit -m "init repo" # create some refs $ git checkout -b sura $ git checkout -b sura-001 $ git checkout -b sura-002 $ git checkout -b sura-003 # show refs $ git for-each-ref d0205e0d0a0a7a6d1a712afb3734ad3e88eeda1c commit refs/heads/master d0205e0d0a0a7a6d1a712afb3734ad3e88eeda1c commit refs/heads/sura d0205e0d0a0a7a6d1a712afb3734ad3e88eeda1c commit refs/heads/sura-001 d0205e0d0a0a7a6d1a712afb3734ad3e88eeda1c commit refs/heads/sura-002 d0205e0d0a0a7a6d1a712afb3734ad3e88eeda1c commit refs/heads/sura-003 # upload-pack, normal, hide 'refs/heads/sura' $ git -c transfer.hiderefs=refs/heads/sura upload-pack .git 0103d0205e0d0a0a7a6d1a712afb3734ad3e88eeda1c HEADmulti_ack thin-pack side-band side-band-64k ofs-delta shallow deepen-since deepen-not deepen-relative no-progress include-tag multi_ack_detailed symref=HEAD:refs/heads/sura object-format=sha1 agent=git/2.46.0 003fd0205e0d0a0a7a6d1a712afb3734ad3e88eeda1c refs/heads/master 0041d0205e0d0a0a7a6d1a712afb3734ad3e88eeda1c refs/heads/sura-001 0041d0205e0d0a0a7a6d1a712afb3734ad3e88eeda1c refs/heads/sura-002 0041d0205e0d0a0a7a6d1a712afb3734ad3e88eeda1c refs/heads/sura-003 0000 # gc make loose refs to packed refs $ git gc # then upload-pack $ git -c transfer.hiderefs=refs/heads/sura upload-pack .git 0103d0205e0d0a0a7a6d1a712afb3734ad3e88eeda1c HEADmulti_ack thin-pack side-band side-band-64k ofs-delta shallow deepen-since deepen-not deepen-relative no-progress include-tag multi_ack_detailed symref=HEAD:refs/heads/sura object-format=sha1 agent=git/2.46.0 003fd0205e0d0a0a7a6d1a712afb3734ad3e88eeda1c refs/heads/master 0000
