infra-git-hooks/pre-commit

#!/usr/bin/env bash
set -o errexit
set -o pipefail

# Updates generated configs if source configs have been modified.

# Assume directory layout as created by infra manifest, and CWD is inside a
# config dir, like fuchsia-infra/config.
LUCICFG="../../fuchsia-infra/prebuilt/tools/lucicfg"
if [[ ! -x "${LUCICFG}" ]]; then
  echo "Expected the following path to be an executable file, but it's not: ${LUCICFG}"
  exit 1
fi

# FILES is an array where each element is a file path.
# We only handle added or modified files, hence the --diff-filter.
# https://git-scm.com/docs/git-diff#git-diff---diff-filterACDMRTUXB82308203
mapfile -t FILES < <(git diff --cached --name-only --diff-filter=AM)

SHOULD_GENERATE=false
for FILE in "${FILES[@]}"; do
  if [[ "${FILE}" == *.star ]]; then
    SHOULD_GENERATE=true
  fi
done

if [[ "${SHOULD_GENERATE}" == true ]]; then
  for TOP_LEVEL_STARLARK in $(ls *.star); do
    "${LUCICFG}" generate "${TOP_LEVEL_STARLARK}"
  done
  git add generated/*.cfg
fi