git-all-the-rebases

#!/bin/bash

# Use an environment variable to know which branch should be used.
if [ -z "$D8_UPSTREAM_BRANCH" ]; then
  echo "Missing the \$D8_UPSTREAM_BRANCH environment variable which must be set to something like '8.7.x'."
  exit 1
fi

current_branch=$(git symbolic-ref --short HEAD)
branch=${1:-${D8_UPSTREAM_BRANCH}}

# Find the current and newest upstream hash.
old=$(git rev-parse --short "$branch")
git fetch -q
new=$(git rev-parse --short origin/"$branch")

# Exit if there have been no new commits.
if [ "$old" == "$new" ]; then
  echo "No new commits."
  exit 0
fi

# Find all branches that were up-to-date before and are now out-of-date.
list=$(git branch --contains "$old" --no-contains "$new" --format='%(refname:short)')

# Count the number of branches.
total=$(echo "$list" | wc -l | awk '{print $1}')

# If there are no out-of-date branches, exit.
if [ "$total" -eq 0 ]; then
  echo "No branches need rebasing."
  exit 0
fi

# Loop through all of the out-of-date branches.
commitnum=$(git rev-list --count "$old".."$new")
echo "Rebasing $total branches $commitnum commits from $old to $new"
count=0
rebase=()
for ref in $list; do
  if ! (sudo git checkout -q "$ref"); then
    sudo git checkout -- sites/default >/dev/null 2>&1
  fi
  # Attempt to rebase the branch, adding it to the list and aborting the rebase
  # if it fails.
  if ! (sudo git rebase -q origin/"$branch" >/dev/null 2>&1); then
    rebase+=("$ref")
    sudo git rebase --abort
  fi
  sudo git checkout -- sites/default >/dev/null 2>&1

  # Print a progress bar.
  count=$(( $count + 1 ))
  printf "\r%3d%% done, %s failed" $(( $count * 100 / $total )) ${#rebase[@]}
done
printf "\n"

if [ ${#rebase[@]} -ne 0 ]; then
  printf "\n"
  echo "The following branches failed rebasing:"
  printf "\n"
  printf "%s\n" "${rebase[@]}"
  sudo git checkout -q "$current_branch"
else
  # If all branches were successfully rebased, perform any custom rebasing.
  #git checkout -q ____ && git rebase -q ____ && \
  sudo git checkout -q "$current_branch"
fi

sudo chown -R `whoami` core
sudo chown -R `whoami` .git

printf "\n"
echo "Rebasing took $SECONDS seconds."