git-update-parent-branch

#!/bin/bash
# Updates the base or parent branch
CURRENT_BRANCH="$(git current-branch)"
PARENT_BRANCH=""
COMMIT_MODE="multi-commit"
UNTIL_COMMIT=""
COMMITS=""

while getopts ":-:" opt; do
  case ${opt} in
    -)
      case ${OPTARG} in
        "single-commit"*) COMMIT_MODE="single-commit";;
      esac
  esac
done

if [ "$COMMIT_MODE" == "single-commit" ]; then
  if [ "$2" == "" ]; then
    PARENT_BRANCH="$(git parent-branch)"
  else
    PARENT_BRANCH="$2"
  fi
  COMMITS="$(git rev-parse "$CURRENT_BRANCH")"
else
  if [ "$1" == "" ]; then
    PARENT_BRANCH="$(git parent-branch)"
    COMMITS="$(git rev-list "$CURRENT_BRANCH"..."$PARENT_BRANCH")"
  else
    PARENT_BRANCH="$1"
    COMMON_ANCESTOR="$(git merge-base "$CURRENT_BRANCH" "$PARENT_BRANCH")"
    COMMITS="$(git rev-list "$CURRENT_BRANCH"..."$COMMON_ANCESTOR")"
  fi

  if [ "$2" != "" ]; then
    UNTIL_COMMIT="$2"
  fi
fi
# TODO - What if we don't have commits?

echo "CURRENT BRANCH -> $CURRENT_BRANCH"
echo "PARENT BRANCH -> $PARENT_BRANCH"
echo "COMMIT LIST -> $COMMITS"
echo "----"

# TODO - What if a checkout fails?
git checkout -b "$CURRENT_BRANCH-temp"
git fetch

git checkout "$PARENT_BRANCH" > /dev/null 2>&1
git branch -D "$CURRENT_BRANCH" > /dev/null 2>&1
git checkout -b "$CURRENT_BRANCH" > /dev/null 2>&1

# TODO - What if a cherry-pick fails?
if [ "$COMMIT_MODE" == "single-commit" ]; then
  echo "----"
  echo "Cherry Picking -> $COMMITS"
  git cherry-pick "$COMMITS"
else
  echo 'Multi Commit Mode Enabled!'
  COMMIT_ARRAY=($COMMITS)
  COMMITS_TO_CHERRY=()

  if [ "$UNTIL_COMMIT" != "" ]; then
    for commit_id in "${COMMIT_ARRAY[@]}"
    do
      if [[ "$commit_id" =~ "$UNTIL_COMMIT" ]]; then
        break
      fi
      COMMITS_TO_CHERRY+=("$commit_id")
    done
  fi
  
  size=${#COMMITS_TO_CHERRY[@]}
  for (( i=size-1; i>=0; i-- )); do
    echo "----"
    if [[ "${COMMITS_TO_CHERRY[i]}" =~ "$UNTIL_COMMIT" ]]; then
      echo "NOT Cherry Picking! -> ${COMMITS_TO_CHERRY[i]}"
    else
      echo "Cherry Picking -> ${COMMITS_TO_CHERRY[i]}"
      git cherry-pick "${COMMITS_TO_CHERRY[i]}"
    fi
  done
fi

echo "----"
git push --set-upstream origin -f "$CURRENT_BRANCH"

git log --oneline --color --decorate --graph --all