git-branchstack-pick

#!/bin/sh

NAME="git ${0##*/git-}"
usage() {
	echo "\
usage: $NAME <base_commit>..<commit> [<rebase-args>...]
       $NAME ..<commit> [<rebase-args>...]

Start a new interactive rebase, with these steps planned:
- drop commits whose subjects start with \"[<topic>] \"
- cherry-pick the given commit range and prefixes subjects with \"[<topic>] \"

where <topic> is <commit> but with one leading path component removed.
For example, <commit> can look like <remote>/<topic>.

Arguments beyond the first are passed on to git-rebase(1)." && exit 1
}

if [ -z "$1" ] || [ "$1" = "-h" ]; then
	usage
fi
range=$1
shift

if ! printf %s "$range" | grep -qF ..; then
	echo "$NAME: argument must be a valid 'a..b' range: '$range'"
	exit 1
fi

remote_branch=${range#*..} # Right part of range.
topic=${remote_branch}
if [ "${remote_branch#refs/}" != "${remote_branch}" ]; then
	topic=gitref/${remote_branch#refs/} # Drop "refs/" to avoid ambiguous ref.
elif git remote | grep -qxF -- "${remote_branch%%/*}"; then
	topic=${remote_branch#*/} # Drop remote.
fi
base_commit=${range%%..*} # Left part of range.
base_commit=${base_commit:-$remote_branch} # This is good enough if the remote is not stale.

prefix=$(git config branchstack.subjectPrefixPrefix || echo [)
suffix=$(git config branchstack.subjectPrefixSuffix || echo ])

pick=pick
drop=drop
exec=exec
if [ "$(git config rebase.abbreviateCommands)" = true ]; then
	pick=p
	drop=d
	exec=x
fi

cherries=$(
	git log --reverse --format="$pick %h $prefix${topic}$suffix %s" "$range"
)
if ! [ "$cherries" ]; then
	echo "$NAME: nothing to cherry-pick from $range"
	exit 0
fi

todo=$(IFS='
'
for cherry in $cherries
do
	printf "%s\n$exec %s\n" \
		"$cherry" \
		"GIT_EDITOR='perl -pi -e \"s{^}{$prefix${topic}$suffix } if $. == 1\"' git commit --amend --allow-empty"
done
)
todo=$todo \
editor=${GIT_SEQUENCE_EDITOR:-$(git var GIT_EDITOR)} \
topic=$topic prefix=$prefix suffix=$suffix \
pick=$pick drop=$drop \
GIT_SEQUENCE_EDITOR='
	perl -pi -e '\''
		use Env;
		if (m/^$pick \S+ \Q$prefix$topic\E(?::[^ ]+?)?\Q$suffix /) {
			s/^$pick/$drop/;
			$dropped_any = 1;
		} elsif ($todo and ($dropped_any or m/^$/)) {
			$_ = $todo . "\n" . $_;
			$todo = "";
		}
		END { exec "$editor .git/rebase-merge/git-rebase-todo"; }
	'\''' git rebase -i --no-autosquash "$(git merge-base "$base_commit" HEAD)" "$@"