Update `hack/verify-shellcheck.sh`

[guettli]

/kind feature

I think our hack/verify-shellcheck.sh is outdated. We could use something like this:

#!/usr/bin/env bash

# TODO: Add Boilerplate

# Bash Strict Mode: https://github.com/guettli/bash-strict-mode
trap 'echo -e "\n🤷 🚨 🔥 Warning: A command has failed. Exiting the script. Line was ($0:$LINENO): $(sed -n "${LINENO}p" "$0" 2>/dev/null || true) 🔥 🚨 🤷 "; exit 3' ERR
set -Eeuo pipefail

# https://github.com/koalaman/shellcheck/releases
SHELLCHECK_VERSION="v0.11.0"

# disabled lints
disabled=(
  # this lint disallows non-constant source, which we use extensively without
  # any known bugs
  1090
  # this lint prefers command -v to which, they are not the same
  2230

  1091
)

OS="unknown"
if [[ "${OSTYPE}" == "linux"* ]]; then
  OS="linux"
elif [[ "${OSTYPE}" == "darwin"* ]]; then
  OS="darwin"
fi

# comma separate for passing to shellcheck
join_by() {
  local IFS="$1"
  shift
  echo "$*"
}
# shellcheck source=./hack/utils.sh
# shellcheck disable=SC1091
source "$(dirname "$0")/lib/utils.sh"
ROOT_PATH=$(get_root_path)

# create a temporary directory
TMP_DIR=$(mktemp -d)
OUT="${TMP_DIR}/out.log"

SHELLCHECK_DISABLED="$(join_by , "${disabled[@]}")"
readonly SHELLCHECK_DISABLED

SHELLCHECK="./$(dirname "$0")/tools/bin/shellcheck/${SHELLCHECK_VERSION}/shellcheck"

if [ ! -f "$SHELLCHECK" ]; then
  # install buildifier
  cd "${TMP_DIR}" || exit
  DOWNLOAD_FILE="shellcheck-${SHELLCHECK_VERSION}.${OS}.x86_64.tar.xz"
  curl -L "https://github.com/koalaman/shellcheck/releases/download/${SHELLCHECK_VERSION}/${DOWNLOAD_FILE}" -o "${TMP_DIR}/shellcheck.tar.xz"
  tar xf "${TMP_DIR}/shellcheck.tar.xz"
  cd "${ROOT_PATH}"
  mkdir -p "$(dirname "$0")/tools/bin/shellcheck/${SHELLCHECK_VERSION}"
  mv "${TMP_DIR}/shellcheck-${SHELLCHECK_VERSION}/shellcheck" "$SHELLCHECK"
fi

echo "Running shellcheck..."
cd "${ROOT_PATH}" || exit
ALL_SH_FILES="${TMP_DIR}/all-sh-files.txt"
OUR_SH_FILES="${TMP_DIR}/filtered-sh-files.txt"
EXCLUDED_SH_FILES="${TMP_DIR}/excluded-sh-files.txt"
EXCLUDED_FILE_PATTERN='/vendor/|hack/version.sh|/node_modules/'

find . -type f -name "*.sh" | sort >"${ALL_SH_FILES}"

grep -P -v "${EXCLUDED_FILE_PATTERN}" "${ALL_SH_FILES}" >"${OUR_SH_FILES}" || true

# Set operation: All files, minus our sh files.
comm -23 "${ALL_SH_FILES}" "${OUR_SH_FILES}" >"${EXCLUDED_SH_FILES}"

#if [[ -s "${EXCLUDED_SH_FILES}" ]]; then
#  echo "$(pwd) Ignoring shellcheck on:"
#  cat "${EXCLUDED_SH_FILES}"
#fi

while read -r file; do
  "$SHELLCHECK" -x "--exclude=${SHELLCHECK_DISABLED}" "--color=auto" "$file" >>"${OUT}" 2>&1 || true
done <"${OUR_SH_FILES}"

if [[ -s "${OUT}" ]]; then
  echo "Found errors:"
  cat "${OUT}"
  echo
  echo 'Please review the above warnings. You can test via "./hack/verify-shellcheck.sh"'
  echo 'If the above warnings do not make sense, you can exempt this warning with a comment'
  echo ' (if your reviewer is okay with it).'
  echo 'In general please prefer to fix the error, we have already disabled specific lints.'
  echo 'See: https://github.com/koalaman/shellcheck/wiki/Ignore#ignoring-one-specific-instance-in-a-file'
  echo
  exit 1
fi
echo 'Congratulations! All shell files are passing lint :-)'