git-trigger-build: Triggers a CI build by pushing an empty commit

git-trigger-build.sh

#!/bin/bash -e
# Stash the staged files if any.
NEEDS_UNSTASH=0
if ! git diff --staged --exit-code >/dev/null; then
  echo -ne '\033[1;32m'
  echo -n 'Stashing the staged files'
  echo -e '\033[0m'
  git stash
  NEEDS_UNSTASH=1

  # Ensure there are no staged files anymore
  git diff --staged --exit-code >/dev/null
fi

COMMIT_DATE="$(date)"
COMMIT_MSG="Trigger build ($COMMIT_DATE)"
if git diff --exit-code HEAD~ >/dev/null; then
  # Amend the last commit since it's empty already.
  echo -ne '\033[1;32m'
  echo -n 'Force-pushing the last empty commit'
  echo -e '\033[0m'
  git commit --allow-empty --amend --date="$COMMIT_DATE" --message="$COMMIT_MSG"
  git push --force
else
  # Create a new empty commit since the last commit is not empty.
  echo -ne '\033[1;32m'
  echo -n 'Pushing an empty commit'
  echo -e '\033[0m'
  git commit --allow-empty --message="$COMMIT_MSG"
  git push
fi

# Unstash if stashed above.
if [[ "$NEEDS_UNSTASH" -ne 0 ]]; then
  echo -ne '\033[1;32m'
  echo -n 'Unstashing the staged files'
  echo -e '\033[0m'
  git stash pop
fi