scripts/autopick.sh

#!/bin/bash
set -e
get_patch_id_commit_id_pairs() {
	git log "$@" --pretty=tformat:'COMMITm@g1c %H %al %as %f%n%B' | awk 'function p(){if(h){print(d?d:c?c:g?g:(a":"t":"s)),h}};$1=="COMMITm@g1c"{p();h=$2;a=$3;t=$4;s=$5;c=d=g="";next};$1=="Differential"&&$2=="Revision:"{d=$3;sub("http.*/","",d);next};$1=="Change-Id:"{c=$1$2;next};$1=="git-svn-id:"{g=$2;next};END{p()}'
}

if [ -z "$1" ]; then
	echo "Usage: `basename "$0"` branch_to_auto_pick_from"
	exit
fi
FROM_BRANCH="$1"
TO_BRANCH="$(git rev-parse --abbrev-ref HEAD)"
if [ -z "$TO_BRANCH" ]; then
	echo "Please git checkout to a branch first"
	exit 1
fi

echo "Computing merge base from $FROM_BRANCH to $TO_BRANCH ..."
MERGE_BASE="$(git merge-base --all "$FROM_BRANCH" "$TO_BRANCH")"
if [ -z "$MERGE_BASE" ]; then
	echo "Failed to get merge base"
	exit 1
elif [ $(wc -l <<< "$MERGE_BASE") -gt 1 ]; then
	echo "Git tree with cross merge not supported"
	exit 1
fi
echo "Merge base is $(get_patch_id_commit_id_pairs $MERGE_BASE^..$MERGE_BASE)"

echo -n "Getting patch list on $FROM_BRANCH ... "
declare -A MAP_FROM_PATCHES
REV_LIST_FROM_PATCHES=
while read c d; do
	if [ -n "$(exec 2>/dev/null; echo ${MAP_FROM_PATCHES[$c]})" ]; then
		echo "Duplicate patch name found for $c $d ${MAP_FROM_PATCHES[$c]}"
		d="$d ${MAP_FROM_PATCHES[$c]}"
	fi
	MAP_FROM_PATCHES[$c]="$d"
	REV_LIST_FROM_PATCHES="$c
$REV_LIST_FROM_PATCHES"
done < <(get_patch_id_commit_id_pairs "$MERGE_BASE..$FROM_BRANCH")
echo "${#MAP_FROM_PATCHES[@]} patches"

echo -n "Getting patch list on $TO_BRANCH ... "
declare -A MAP_TO_PATCHES
declare -A MAP_TO_PATCHES_DUP
while read c d; do
	if [ -n "$(exec 2>/dev/null; echo ${MAP_TO_PATCHES[$c]})" ]; then
		echo "Duplicate patch name found for $c $d ${MAP_TO_PATCHES[$c]}"
		d="$d ${MAP_TO_PATCHES[$c]}"
		MAP_TO_PATCHES_DUP[$c]="$d"
	fi
	MAP_TO_PATCHES[$c]="$d"
done < <(get_patch_id_commit_id_pairs "$MERGE_BASE..$TO_BRANCH")
echo "${#MAP_TO_PATCHES[@]} patches"
for d in ${MAP_TO_PATCHES_DUP[@]}; do
	HASH="$(git diff --binary $d^..$d | sha1sum | cut -d ' ' -f 1)"
	eval "HAS_$HASH=true"
done

echo "Computing patches to cherry-pick ..."
PATCHES_TO_PICK=
while read c; do
	if [ -z "$c" ]; then
		continue
	fi
	if [ -z "$(exec 2>/dev/null; echo ${MAP_TO_PATCHES[$c]})" ] || [ ${#MAP_FROM_PATCHES[$c]} -ne ${#MAP_TO_PATCHES[$c]} ]; then
		echo -ne "$c\t"
		if [[ "${MAP_FROM_PATCHES[$c]}" == *" "* ]]; then
			if [ -z "$(exec 2>/dev/null; echo ${MAP_TO_PATCHES_DUP[$c]})" ]; then
				for d in ${MAP_TO_PATCHES[$c]}; do
					HASH="$(git diff --binary $d^..$d | sha1sum | cut -d ' ' -f 1)"
					eval "HAS_$HASH=true"
				done
			fi
			for d in ${MAP_FROM_PATCHES[$c]}; do
				if [ -z "$(eval echo "\${VISITED_$d}")" ]; then
					break
				fi
			done
			if [ -n "$(eval echo "\${VISITED_$d}")" ]; then
				echo "All patches visited for $c: ${MAP_FROM_PATCHES[$c]}"
				exit 1
			fi
			eval "VISITED_$d=true"
			HASH="$(git diff --binary $d^..$d | sha1sum | cut -d ' ' -f 1)"
			if [ -n "$(eval echo "\${HAS_$HASH}")" ]; then
				echo "$d skipped"
				continue
			fi
			c="$c-$HASH"
			MAP_FROM_PATCHES[$c]="$d"
		fi
		echo "${MAP_FROM_PATCHES[$c]}"
		PATCHES_TO_PICK="$PATCHES_TO_PICK
$c"
	fi
done <<< "$REV_LIST_FROM_PATCHES"
while read c; do
	if [ -z "$c" ]; then
		continue
	fi
	d="${MAP_FROM_PATCHES[$c]}"
	echo "Cherry-picking $d for $c ..."
	git cherry-pick "$d"
done <<< "$PATCHES_TO_PICK"

echo "Done"