git-atomic-update

#!/usr/bin/env bash

function _display_help {
  echo ""
  echo "==============================================================================="
  echo "Atomic branch update tool:"
  echo -e "\tThis command assists in maintaining a series of branches that are used to"
  echo -e "\tenforce an atomic commit behavior at the PR level.  It assumes the each"
  echo -e "\tbranch properly declares a dependency on another branch until it reaches"
  echo -e "\tthe branch origin."
  echo ""
  echo -e "Example update:"
  echo -e "\tcurrent branch is: jdoe0001/issue_401_fix_layer"
  echo -e "\t$ git atomic-update"
  echo -e "\tThis will walk down the parent branches until it reaches master at which point"
  echo -e "\tit begins to update the branches to include all changes back to the parent."
  echo ""
  echo -e "\tEach branch contains a single commit work item, and may contain CR corrections."
  echo -e "\tLive Simply."
  echo ""
  echo -e "Optional flags:"
  echo -e "\t--push\tPublish local commits found on each branch visited"
  echo -e "\t-h\tDisplay this menu"
  echo "==============================================================================="
  echo ""
}

REPO_REMOTE="$(git remote)"
DEFAULT_BRANCH=$(git remote show "${REPO_REMOTE}" | awk '/HEAD branch/ {print $NF}')

start_branch=
branch_prefix=

function _do_update {
  local branch_name="${1}"
  local stop_recursion="false"
  local parent_branch=

  parent_branch=$(git rev-parse --abbrev-ref --symbolic-full-name @{u})

  #
  # Recursively call down to build a stack up until we reach the
  # origin of everything
  #
  if [ -n "${branch_name}" ]; then
    if [[ "${parent_branch}" = "${REPO_REMOTE}/"* ]]; then
      stop_recursion="true"
    fi

    if [ "${branch_name}" = "${DEFAULT_BRANCH}" ]; then
      stop_recursion="true"
    fi

    if [ "${stop_recursion}" != "true" ]; then
      git checkout "${parent_branch}"
      _do_update "${parent_branch}"
      git checkout "${branch_name}"
    fi
  fi

  git pull --prune --rebase || exit #?
  if [ -n "${branch_prefix}" ] && [ "$(git rev-list --count ${parent_branch}..HEAD)" -ne 0 ]; then
    git push "${REPO_REMOTE}" "${branch_name}:${branch_prefix}${branch_name}" --force-with-lease || exit $?
  fi
}

if [ -n "${1}" ]; then
  case "${1}" in
    --push)
      if ! branch_prefix=$(git config --get user.email)
      then
        echo "Global git user.email is not set. Local commits will not be published"
        branch_prefix=
        break
      fi
      branch_prefix="$(echo ${branch_prefix} | awk -F"@" '{print $1}')/"
      ;;
    *)
    _display_help
    exit
    ;;
    esac
fi

if ! start_branch=$(git symbolic-ref --short -q HEAD)
then
  echo "Currently not on a branch, this script can only work on an active branch"
  exit 1
fi

_do_update "${start_branch}"