Jujutsu workflow for advancing a bookmark after creating a commit.

jj-commit-onto-bookmark.sh

#!/usr/bin/env bash
# Add to jj config:
# [aliases]
# cob = ["util", "exec", "--", "jj-commit-onto-bookmark.sh"]
set -euo pipefail

target_bookmark=""
target_bookmark_revset=""
commit_args=()

usage() {
    cat <<EOF
Usage:
  jj cob (-b|--bookmark BOOKMARK | -r|--revisions BOOKMARK_REVSET [default: @-])
         [-i|--interactive]
         [-m|--message MESSAGE]
         [FILESETS]
         [-- jj commit advanced-args...]

Rebase the working copy commit onto a bookmark with a description and update the bookmark.

This is useful in two scenarios:
1. Advancing a bookmark from old @- after creating a new commit on top. This is the default behavior of jj cob and behaves like jj commit --advance-branches feature would.
2. Inserting a commit onto a feature branch when using the megamerge workflow and advancing that bookmark when using -b or -r

By default if no arguments are specified, the bookmark is assumed to be at @-.
Otherwise exactly one of -b/--bookmark or -r/--revisions must be specified.

-i/--interactive and -m/--message are forwarded to 'jj commit' automatically.
Other commit options must be preceded by --.
EOF
    exit 1
}

# Parse options
while [[ $# -gt 0 ]]; do
    case "$1" in
        -b|--bookmark)
            [[ -n "$target_bookmark_revset" ]] && usage
            shift || usage
            target_bookmark="$1"
            shift
            ;;
        -r|--revisions)
            [[ -n "$target_bookmark" ]] && usage
            shift || usage
            target_bookmark_revset="$1"
            shift
            ;;
        -i|--interactive)
            commit_args+=("$1")
            shift
            ;;
        -m|--message)
            commit_args+=("$1")
            shift || usage
            commit_args+=("$1")
            shift
            ;;
        --)
            shift
            # Forward everything else verbatim to jj commit
            commit_args+=("$@")
            break
            ;;
        -*)
            echo "Unknown option: $1" >&2
            usage
            ;;
        *)
            commit_args+=("$@")
            break
            ;;
    esac
done

# Default to @- if neither was specified
if [[ -z "$target_bookmark" && -z "$target_bookmark_revset" ]]; then
    target_bookmark_revset="@-"
fi

# Resolve bookmark from revset if needed
if [[ -z "$target_bookmark" ]]; then
    bookmarks="$(
        jj --ignore-working-copy log \
           --revisions "$target_bookmark_revset" \
           --no-graph \
           --template 'local_bookmarks ++ " "'
    )"

    read -r -a bookmark_array <<<"$bookmarks"

    case "${#bookmark_array[@]}" in
        0)
            echo "No local bookmarks found at revision: $target_bookmark_revset" >&2
            exit 1
            ;;
        1)
            # Remove trailing * in case it's a local bookmark that has diverged
            target_bookmark="${bookmark_array[0]%\*}"
            ;;
        *)
            echo "Multiple local bookmarks found at revision $target_bookmark_revset:" >&2
            for b in "${bookmark_array[@]}"; do
                echo "  $b" >&2
            done
            echo "Please specify one with --bookmark." >&2
            exit 1
            ;;
    esac
else
    if ! jj --ignore-working-copy log \
            --revisions "$target_bookmark" \
            --no-graph \
            --template 'local_bookmarks ++ " "' \
            >/dev/null 2>&1
    then
        echo "Error: bookmark '$target_bookmark' does not exist or is not resolvable." >&2
        exit 1
    fi
fi

jj commit --quiet ${commit_args[@]+"${commit_args[@]}"}

new_change_id="$(jj --ignore-working-copy log --revisions @- --no-graph --template change_id)"

# Rebase will be skipped if it's not necessary
jj --ignore-working-copy rebase --revisions "$new_change_id" --insert-after "$target_bookmark" --quiet

jj --ignore-working-copy bookmark move "$target_bookmark" --to "$new_change_id" --quiet

jj status