utils.sh

# Helper utilities for GitHub Actions jobs.
# To include: source ./tools/ci/utils.sh

# Print files modified in this pull request branch (and not deleted).
# Usage: readarray -t changed_files < <(get_changed_files)
get_changed_files() {
  local compared_branch="${1:-master}"

  while read fp; do
    # Ignore files that no longer exist.
    if [[ -e "$fp" ]]; then
      echo "$fp"
    fi
  done < <(git diff --name-only "$compared_branch" || true)
  # TODO: Only list files modified on *this* branch.
  # `git diff --name-only "$compared_branch"...` doesn't work on shallow clones.
}

# Add label(s) to GitHub issue.
# Requires environment variables `ISSUE_URL` and `GITHUB_TOKEN`.
add_label() {
  local label
  # Deduplicate args.
  declare -A labels_set
  for label in "$@"; do
    labels_set["$label"]=1
  done

  # Collect labels and join with comma.
  local i=1 len="${#labels_set[@]}" item items
  for label in "${!labels_set[@]}"; do
    item=$(printf '"%s"' "$label")
    items="${items}${item}"

    if (( i < len )); then items="${items}, "; fi
    ((i+=1))
  done

  # Create the JSON payload.
  local json_str=$(printf '{"labels": [%s]}' "$items")

  if [[ -z "ISSUE_URL" ]]; then
    echo "[utils:add_label] Requires env variable: ISSUE_URL" >&2
    exit 1
  fi

  if [[ -z "$GITHUB_TOKEN" ]]; then
    echo "[utils:add_label] Requires env variable: GITHUB_TOKEN" >&2
    exit 1
  fi

  curl -X POST \
       -H "Accept: application/vnd.github.v3+json" \
       -H "Authorization: token ${GITHUB_TOKEN}" \
       "${ISSUE_URL}/labels" \
       --data "$json_str"
}

# Add comment to GitHub issue.
# Requires environment variables `ISSUE_URL` and `GITHUB_TOKEN`.
add_comment() {
  local message="$1"

  if [[ -z "ISSUE_URL" ]]; then
    echo "[utils:add_comment] Requires env variable: ISSUE_URL" >&2
    exit 1
  fi

  if [[ -z "$GITHUB_TOKEN" ]]; then
    echo "[utils:add_comment] Requires env variable: GITHUB_TOKEN" >&2
    exit 1
  fi

  # Escape string for JSON.
  local body="$(echo -n -e $message \
          | python3 -c 'import json,sys; print(json.dumps(sys.stdin.read()))')"
  local json_str=$(printf '{"body": %s}' "$body")

  curl -X POST \
       -H "Accept: application/vnd.github.v3+json" \
       -H "Authorization: token $GITHUB_TOKEN" \
       "${ISSUE_URL}/comments" \
       --data "$json_str"
}

# Create new commit and push. Requires `GITHUB_ACTOR` env variable.
# If no files changed, exit without commit.
push_commit() {
  local message="$1"

  if [[ -z "$GITHUB_ACTOR" ]]; then
    echo "[utils:push_commit] Requires env variable: GITHUB_ACTOR" >&2
    exit 1
  fi

  cd "$(git rev-parse --show-toplevel)"  # Move to repo root.

  # Exclude this file from commit if checked out from elsewhere.
  if git ls-files --modified --error-unmatch ./tools/ci/utils.sh > /dev/null 2>&1; then
    git restore -- ./tools/ci/utils.sh
  fi

  if [[ -z $(git ls-files --modified) ]]; then
    echo "[utils:push_commit] No files changed, exiting."
    exit 0
  fi

  # Set author and commit.
  git config --global user.name "$GITHUB_ACTOR"
  git config --global user.email "$[e-mail]"
  git commit --all --message "$message"
  # Push to the current branch.
  git push
}