Sync a massive git repo from local to remote

sync-git.sh

TARGET_BRANCH='upstream/release'
BATCH_SIZE=10000

range=HEAD

git fetch $REMOTE $TARGET_BRANCH

# check if the branch exists on the remote
if git show-ref --quiet --verify refs/remotes/$REMOTE/$TARGET_BRANCH; then
    # if so, only push the commits that are not on the remote already
    range=$REMOTE/$TARGET_BRANCH..HEAD
else
    # else push all the commits
    range=HEAD
fi


echo "Range: $range"

# count the number of commits to push
n=$(git log --first-parent --format=format:x $range | wc -l)

echo "Commits to push: $n"

# push each batch
for i in $(seq $n -$BATCH_SIZE 1); do
    # get the hash of the commit to push
    h=$(git log --first-parent --reverse --format=format:%H --skip $i -n1)
    echo "Pushing $h..."
    git push $REMOTE $h:refs/heads/$TARGET_BRANCH # --force
done

# push the final partial batch
git push $REMOTE HEAD:refs/heads/$TARGET_BRANCH