Closest equivalent for git describe --tags?

[BatmanAoD]

I really like using git describe --tags as an easy way to generate a version string. It has the following advantages:

• Extremely simple
• Always uniquely identifies the state of the code (as long as versions are not reassigned)
• If the current HEAD is on a commit corresponding to a release tag, you get that release version
• The commit-info is formatted as a valid semver prerelease tag; thus, if the version tags used are semver-compatible, the generated string is always semver-compatible

Is there anything like this in jj? For collocated repos git describe --tags works, but I think it would be good to have a native command that behaves similarly.

[moderation]

I had a similar question and just found https://github.com/hymkor/jjtagdesc. It doesn't look like it works anymore probably due to output changes in jj but it might provide some ideas

[shanesveller]

Loosely borrowed a few small particulars from this, and I came up with:

jj log -r 'latest(tags())::@- ~ empty()' --no-graph --reversed -T 'commit_id.short(10) ++ " " ++ tags ++ "\n"' \
| awk '{latest = $1; count++}; $2 != "" && tag == "" { tag = $2 } END {print tag "-" count "-" latest}'

My awk skill level is atrocious, so it can probably be golfed down some more. Tested with jj 0.25.0.

[moderation]

This is awesome. Thanks for sharing. I converted to a Fish shell function which is working well:

# https://github.com/jj-vcs/jj/discussions/2563
function jj_describe --description 'replicate git describe --tags for jj'
    
    set count 0
    set tag ""
    set latest_commit ""

    set jj_output (jj log -r 'latest(tags())::@- ~ empty()' --no-graph --reversed -T 'commit_id.short(10) ++ " " ++ tags ++ "\n"')

    for line in $jj_output
        set count (math $count + 1)
        set -l parts (string split " " $line)
        set latest_commit $parts[1]

        if test (count $parts) -gt 1; and test -z "$tag"
            set tag (string sub --start 2 $parts[2])
        end
    end

    printf "%s-%d-%s\n" $tag $count $latest_commit

end