scripts: Add a script for backport handling.

#!/usr/bin/env bash

#  SPDX-License-Identifier: BSD-3-Clause

#  Copyright (C) 2023 Intel Corporation

#  All rights reserved.

GERRIT_USER=""

HASHTAG=""

BACKPORT_DIR=""

SPDK_DIR=""

CHERRY_PICK_TEMP=""

FROM_BRANCH=""

function cleanup() {

	rm -rf "$BACKPORT_DIR"/cherry*

	rm -rf "$TMP_DIR"

}

function display_help() {

	echo " Usage: ${0##*/} [-u <gerrit_user>] [-t <hashtag>] [-d <spdk_dir>]

	Script automating Git operations to submit patches to different branches.

	  -d    Path for SPDK repository and temporary files used for backporting.

	  -t	Hashtag on patches to be backported and destination SPDK version (e.g. 23.05).

	  -u	Gerrit username.

	  -h	Show this help message.

	SHH authentication for provided Gerrit user is required.

	Merged commits from 'master' branch with provided hashtag (eg. 23.05) are cherry-picked

	to release branch (v23.05.x) in order they were merged. Skipping commits already present

	on the release branch.

	If merge conflict occurs during cherry-pick, it needs to be resolved manually.

	Then calling this script again will resume further cherry-picks.

	Example:

	./scripts/backport.sh -u gerrit_user -t 23.05 -d ./backports"

}

function reorder_commits() {

	local unordered_list=$1

	local from="v${HASHTAG}-rc1"

	git -C "$SPDK_DIR" fetch origin

	# Reorder commits to how they were merged to master

	git -C "$SPDK_DIR" show -s --format="%H" "$from^..HEAD" | tac > "$TMP_DIR/ordered_commits"

	mapfile -t u < "$unordered_list"

	mapfile -t o < "$TMP_DIR/ordered_commits"

	cp=()

	for ((i = 0; i < ${#u[@]}; i++)); do

		for ((j = 0; j < ${#o[@]}; j++)); do

			if [[ "${u[i]}" == "${o[j]}" ]]; then

				cp[j]=${u[i]}

			fi

		done

	done

	printf '%s\n' "${cp[@]}"

}

function fix_up_commit_msg() {

	local hash=$1

	git show -s --format="%B" "$hash" > $SPDK_DIR/msg

	# Add '(master)' info to link for original review

	sed -i '/Reviewed-on/ s/$/ (master)/' $SPDK_DIR/msg

	# Remove all tags added on original patches merged regarding reviewers and testers

	sed -i '/^Reviewed-by/d' "$SPDK_DIR/msg"

	sed -i '/^Community-CI/d' "$SPDK_DIR/msg"

	sed -i '/^Tested-by/d' "$SPDK_DIR/msg"

	echo "(cherry picked from commit $hash)" >> "$SPDK_DIR/msg"

	grep "^Change-Id" "$SPDK_DIR/msg" > "$SPDK_DIR/id"

	sed -i '/^Change-Id/d' "$SPDK_DIR/msg"

	cat "$SPDK_DIR/id" >> "$SPDK_DIR/msg"

	git commit -s --amend -m "$(cat $SPDK_DIR/msg)"

	rm -f "$SPDK_DIR/msg"

	rm -f "$SPDK_DIR/id"

}

while getopts "d:ht:u:" opt; do

	case "${opt}" in

		d)

			BACKPORT_DIR="$OPTARG"

			SPDK_DIR="$BACKPORT_DIR/spdk"

			CHERRY_PICK_TEMP="$BACKPORT_DIR/cherry-temp"

			;;

		h)

			display_help >&2

			exit 0

			;;

		t)

			HASHTAG="$OPTARG"

			FROM_BRANCH="v${HASHTAG}.x"

			;;

		u)

			GERRIT_USER="$OPTARG"

			;;

		*)

			display_help >&2

			exit 1

			;;

	esac

done

if [[ -z $HASHTAG || -z $GERRIT_USER || -z $BACKPORT_DIR ]]; then

	echo "Gerrit user, hashtag and directory are required."

	display_help

	exit 1

fi

# Gerrit interactive shells are disabled and attempts to connect with below

# command will result in error code 127, so parse the response instead.

if ! ssh -p 29418 $GERRIT_USER@review.spdk.io 2>&1 | grep -q "Welcome to Gerrit Code Review"; then

	echo "Could not connect to Gerrit"

	exit 1

fi

if [[ -d $SPDK_DIR && -e $SPDK_DIR/.git ]]; then

	echo "Updating SPDK repository."

	git -C "$SPDK_DIR" pull

else

	rm -rf "$SPDK_DIR"

	echo "Cloning SPDK repo"

	git clone "https://review.spdk.io/spdk/spdk" "$SPDK_DIR" --recurse-submodules

fi

cd "$SPDK_DIR"

# Enable git rerere to remember conflict resolution when creating commits to resubmit multiple times

git config --local rerere.enabled true

git config --local rerere.autoupdate true

if [[ ! -f $CHERRY_PICK_TEMP ]]; then

	echo "Creating commit list to cherry-pick"

	TMP_DIR="$BACKPORT_DIR/temp_files"

	if [[ ! -d $TMP_DIR ]]; then

		# If this is not the first run, then the direcotry might already exist

		mkdir "$TMP_DIR"

	fi

	# Get list of hash tagged patches on master branch

	ssh -p 29418 $GERRIT_USER@review.spdk.io gerrit query --format json \

		--current-patch-set project:spdk/spdk status:merged branch:"master" hashtag:"$HASHTAG" > "$TMP_DIR/master_${HASHTAG}_list"

	jq -r 'select(.id != null)|.id' "$TMP_DIR/master_${HASHTAG}_list" | sort > "$TMP_DIR/hash_id"

	# List of patches already submitted to the backporting branch

	ssh -p 29418 $GERRIT_USER@review.spdk.io gerrit query --format json \

		--current-patch-set project:spdk/spdk branch:"$FROM_BRANCH" > "$TMP_DIR/branch_list"

	jq -r 'select(.id != null)|.id' "$TMP_DIR/branch_list" | sort > "$TMP_DIR/branch_id"

	comm -13 "$TMP_DIR/branch_id" "$TMP_DIR/hash_id" > "$TMP_DIR/id_to_port"

	while read -r line; do

		jq -r ". | select(.id == "\"$line\"")" "$TMP_DIR/master_${HASHTAG}_list" \

			| jq -r '.currentPatchSet.revision'

	done < "$TMP_DIR/id_to_port" > "$TMP_DIR/hashtagged"

	reorder_commits "$TMP_DIR/hashtagged" > "$CHERRY_PICK_TEMP"

	git fetch origin

	git checkout $FROM_BRANCH

	git submodule update --init

fi

TOTAL=$(wc -l < "$CHERRY_PICK_TEMP")

echo "Total number of patches to backport: $TOTAL"

cat "$CHERRY_PICK_TEMP" > "$CHERRY_PICK_TEMP.cpy"

while read -r line; do

	cd "$SPDK_DIR"

	if [[ -n $(git status -suno) ]]; then

		if [[ -f "$BACKPORT_DIR/merge_conflict" ]]; then

			# Patch had conflict on previous script call, need to commit and fixup message

			id="$(cat $BACKPORT_DIR/merge_conflict)"

			git commit -C "$id"

			fix_up_commit_msg "$id"

			rm -f "$BACKPORT_DIR/merge_conflict"

		else

			echo "Changes pending, please resolve and commit them"

			exit 1

		fi

	fi

	# Removing new commit to cherry-pick from the list

	tail -n +2 "$CHERRY_PICK_TEMP" > "$CHERRY_PICK_TEMP.tmp" && mv "$CHERRY_PICK_TEMP.tmp" "$CHERRY_PICK_TEMP"

	REMAINING=$(cat $CHERRY_PICK_TEMP | wc -l)

	NR=$((TOTAL - REMAINING))

	echo "Currently at $NR, remaining $REMAINING"

	if [ ! "$(git cherry-pick --rerere-autoupdate $line)" ]; then

		if [[ -z $(git status -suno) ]]; then

			echo "No changes to commit, most likely patch was already merged."

			git cherry-pick --abort

			continue

		fi

		# Git rerere might have already resolved the conflict

		if ! GIT_EDITOR=true git cherry-pick --continue; then

			echo "Merge conflict on patch:"

			echo "$line"

			echo "Use: git mergetool"

			echo "and then call this script again"

			echo "$line" > "$BACKPORT_DIR/merge_conflict"

			exit 1

		fi

	fi

	fix_up_commit_msg "$line"

	echo "Merged"

done < "$CHERRY_PICK_TEMP.cpy"

cd "$SPDK_DIR"

if [[ -f "$BACKPORT_DIR/merge_conflict" ]]; then

	# Patch had conflict on previous script call, need to commit and fixup message

	id="$(cat $BACKPORT_DIR/merge_conflict)"

	git commit -C "$id"

	fix_up_commit_msg "$id"

	rm -f "$BACKPORT_DIR/merge_conflict"

fi

cleanup

echo

echo "The script finished."

echo "Enter $SPDK_DIR, verify the commits at the top of $FROM_BRANCH"

echo "and then call 'git push origin HEAD:refs/for/$FROM_BRANCH' to submit them."