git-submodule-update-and-commit

#!/bin/bash

set -eo pipefail

path="$1"
branch="$2"

if [[ -z "$path" ]]; then
  echo "git-submodule-update-and-commit <path> [<branch>]" 1>&2
  exit 1
fi

if [[ -z "$branch" ]]; then
  echo "No branch given. Obtaining branch from superproject..." 1>&2
  branch=$(git symbolic-ref --short HEAD)
fi


(
  cd "$path"

  if [ ! -z "$(git status --porcelain)" ]; then
    echo "Error: Working directory in $path is not clean." 1>&2
    exit 1
  fi

  echo "Checking out $branch in $path..." 1>&2
  git checkout "$branch"

  echo "Pulling..." 1>&2
  git pull
)

echo "Commiting updated submodule..."
git add "$path"
git commit -m "Update $path" -m "[skip ci]"