#!/usr/bin/env bash set -euo pipefail changed_paths_file="${1:-}" if [[ -z "$changed_paths_file" || ! -f "$changed_paths_file" ]]; then  printf 'Usage: %s <changed-paths-file>\n' "$(basename "$0")" >&2  exit 2fi linux_musl_build=falselinux_musl_build_reason=""path_count=0 require_linux_musl_build() {  local path="$1"  local reason="$2"   linux_musl_build=true  if [[ -z "$linux_musl_build_reason" ]]; then    linux_musl_build_reason="${path}: ${reason}"  fi} classify_path() {  local path="$1"  [[ -z "$path" ]] && return   path_count=$((path_count + 1))   case "$path" in    Package.swift)      require_linux_musl_build "$path" "changes the Swift package manifest"      ;;    Sources/*.swift)      require_linux_musl_build "$path" "changes Swift source code"      ;;  esac} invalid_row=falsewhile IFS=$'\t' read -r status first_path second_path extra_path \  || [[ -n "${status:-}${first_path:-}${second_path:-}${extra_path:-}" ]]do  [[ -z "${status}${first_path:-}${second_path:-}${extra_path:-}" ]] && continue   case "$status" in    R*|C*)      if ! [[ "$status" =~ ^[RC][0-9]{1,3}$ ]] \        || ((10#${status:1} > 100)) \        || [[ -z "${first_path:-}" || -z "${second_path:-}" || -n "${extra_path:-}" ]]      then        invalid_row=true        break      fi      classify_path "$first_path"      classify_path "$second_path"      ;;    A|D|M|T|U|X|B)      if [[ -z "${first_path:-}" || -n "${second_path:-}" || -n "${extra_path:-}" ]]; then        invalid_row=true        break      fi      classify_path "$first_path"      ;;    *)      invalid_row=true      break      ;;  esacdone < "$changed_paths_file" if [[ "$invalid_row" == true ]]; then  printf 'Invalid git name-status row; refusing to skip the Linux musl build.\n' >&2  exit 2fi if [[ "$path_count" -eq 0 ]]; then  require_linux_musl_build '<empty diff>' 'no changed paths were reported'fi if [[ "$linux_musl_build" == true ]]; then  summary_reason="$linux_musl_build_reason"else  summary_reason="no Swift source or Package.swift changes"fi if [[ -n "${GITHUB_OUTPUT:-}" ]]; then  printf 'linux-musl-build=%s\n' "$linux_musl_build" >> "$GITHUB_OUTPUT"  printf 'linux-musl-build-reason=%s\n' "$summary_reason" >> "$GITHUB_OUTPUT"fi if [[ "$linux_musl_build" == true ]]; then  printf 'Linux musl build required for this change set: %s.\n' "$linux_musl_build_reason"else  printf 'Skipping Linux musl build: %s.\n' "$summary_reason"fi