# tags sorted by their depth, *committerdate, and taggerdate 4 messages from 2020-05-06 to 2020-05-07. Participants: clime, Jeff King, brian m. carlson. Thread: https://gitlist.dev/t/53417 ## clime, 2020-05-06 18:16 Subject: tags sorted by their depth, *committerdate, and taggerdate Message-ID: URL: https://gitlist.dev/e/CAGqZTUujRh-f-83A8NYokbxLGZ-bnvGrtguzJsMdg9EX04NsGg%40mail.gmail.com ``` Hello, I have some very specific requirements to get annotated tags sorted in a certain way. I would like them to be sorted: - primarily by their depth (i.e. how far they are from current HEAD and if they are not reachable then they should not be displayed). - secondarily by committerdate of the commit they are associated with - ternarily by taggerdate Is something like that possible? Is something like that possible even with git 1.7.1? If this isn't possible, I am thinking I could write some simple utility in C to do it but can I rely on certain binary format of commit and tag objects? Has the format changed at some point since git 1.7.1? Is there a git library I could use for it? Or is the format documented somewhere? Thank you very much and sorry for so many questions clime ``` ## Jeff King, 2020-05-07 19:42 Subject: Re: tags sorted by their depth, *committerdate, and taggerdate Message-ID: <20200507194224.GB25306@coredump.intra.peff.net> URL: https://gitlist.dev/e/20200507194224.GB25306%40coredump.intra.peff.net In-Reply-To: ``` On Wed, May 06, 2020 at 08:16:35PM +0200, clime wrote: > I have some very specific requirements to get annotated tags sorted in > a certain way. I would like them to be sorted: > - primarily by their depth (i.e. how far they are from current HEAD > and if they are not reachable then they should not be displayed). > - secondarily by committerdate of the commit they are associated with > - ternarily by taggerdate There's no way to compute the depth with for-each-ref or similar. In fact, I'm not even sure of a way to do it for all tags with a single command. So I'd probably script something like: git for-each-ref \ --format='%(*committerdate:unix) %(taggerdate:unix) %(refname)' \ refs/tags | while read cdate tdate ref; do depth=$(git rev-list --count --ancestry-path $ref..HEAD) # if depth is 0, then either $ref isn't an ancestor of HEAD, or $ref # points to the same commit as HEAD. Not sure if you want to salvage # the latter case, but you could compare rev-parse output on the # two. if test "$depth" = 0; then continue fi echo "$depth $cdate $tdate $ref" done | sort -k 3rn -k 2rn -k 1n But it's kind of expensive (we'd walk over the history near HEAD multiple times, once per tag). It seems like git-describe should be able to do a better job of the traversal, but I had trouble convincing it to do so. > Is something like that possible? > Is something like that possible even with git 1.7.1? You'd need v1.7.2 for --ancestry-path. You could just use "$ref..HEAD" without it, and instead do: git merge-base --is-ancestor $ref HEAD to cover the case where they aren't reachable from HEAD. But of course that's an extra traversal per tag. I'm not sure why you need to use such an antique version of Git. > If this isn't possible, I am thinking I could write some simple > utility in C to do it but can I rely on certain binary format of > commit and tag objects? Has the format changed at some point since git > 1.7.1? Is there a git library I could use for it? Or is the format > documented somewhere? Doing better would require a custom traversal of the commits. You could look something with libgit2 (which is in C, but has bindings to some other languages). -Peff ``` ## clime, 2020-05-07 19:47 Subject: Re: tags sorted by their depth, *committerdate, and taggerdate Message-ID: URL: https://gitlist.dev/e/CAGqZTUv_d37_kZAL7KUk_sv4mhga%3DPHJY1jYft6QS95s2jDGjg%40mail.gmail.com In-Reply-To: <20200507194224.GB25306@coredump.intra.peff.net> ``` On Thu, 7 May 2020 at 21:42, Jeff King wrote: > > On Wed, May 06, 2020 at 08:16:35PM +0200, clime wrote: > > > I have some very specific requirements to get annotated tags sorted in > > a certain way. I would like them to be sorted: > > - primarily by their depth (i.e. how far they are from current HEAD > > and if they are not reachable then they should not be displayed). > > - secondarily by committerdate of the commit they are associated with > > - ternarily by taggerdate > > There's no way to compute the depth with for-each-ref or similar. In > fact, I'm not even sure of a way to do it for all tags with a single > command. So I'd probably script something like: > > git for-each-ref \ > --format='%(*committerdate:unix) %(taggerdate:unix) %(refname)' \ > refs/tags | > while read cdate tdate ref; do > depth=$(git rev-list --count --ancestry-path $ref..HEAD) > > # if depth is 0, then either $ref isn't an ancestor of HEAD, or $ref > # points to the same commit as HEAD. Not sure if you want to salvage > # the latter case, but you could compare rev-parse output on the > # two. > if test "$depth" = 0; then > continue > fi > > echo "$depth $cdate $tdate $ref" > done | > sort -k 3rn -k 2rn -k 1n > > But it's kind of expensive (we'd walk over the history near HEAD > multiple times, once per tag). > > It seems like git-describe should be able to do a better job of the > traversal, but I had trouble convincing it to do so. > > > Is something like that possible? > > Is something like that possible even with git 1.7.1? > > You'd need v1.7.2 for --ancestry-path. You could just use "$ref..HEAD" > without it, and instead do: > > git merge-base --is-ancestor $ref HEAD > > to cover the case where they aren't reachable from HEAD. But of course > that's an extra traversal per tag. > > I'm not sure why you need to use such an antique version of Git. > > > If this isn't possible, I am thinking I could write some simple > > utility in C to do it but can I rely on certain binary format of > > commit and tag objects? Has the format changed at some point since git > > 1.7.1? Is there a git library I could use for it? Or is the format > > documented somewhere? > > Doing better would require a custom traversal of the commits. You could > look something with libgit2 (which is in C, but has bindings to some > other languages). Thank you, Jeff. I didn't actually expect somebody would respond to my crazy demand. I probably could drop support for that version, it is in centos:6 but that is soon going to be eoled. Thank you also for the scripts. I would like to be the operation as fast as possible so I am actually considering libgit2 now. Thank you very much again for your advice clime > > -Peff ``` ## brian m. carlson, 2020-05-07 23:56 Subject: Re: tags sorted by their depth, *committerdate, and taggerdate Message-ID: <20200507235659.GD7234@camp.crustytoothpaste.net> URL: https://gitlist.dev/e/20200507235659.GD7234%40camp.crustytoothpaste.net In-Reply-To: <20200507194224.GB25306@coredump.intra.peff.net> ``` On 2020-05-07 at 19:42:24, Jeff King wrote: > On Wed, May 06, 2020 at 08:16:35PM +0200, clime wrote: > > Is something like that possible? > > Is something like that possible even with git 1.7.1? > > You'd need v1.7.2 for --ancestry-path. You could just use "$ref..HEAD" > without it, and instead do: > > git merge-base --is-ancestor $ref HEAD > > to cover the case where they aren't reachable from HEAD. But of course > that's an extra traversal per tag. I believe git merge-base --is-ancestor is much newer than v1.7.1. I think you have to use the old style, which IIRC is this: test "$(git rev-parse "$ref")" = "$(git merge-base "$ref" HEAD)" If you'd like a more modern version for CentOS 6, I think Software Collections has one with suitable support. -- brian m. carlson: Houston, Texas, US OpenPGP: https://keybase.io/bk2204 ```