Developers pulling branches with modified composer.json files frequently forget to run composer install, running outdated dependencies locally and diagnosing bugs that do not exist.
#!/usr/bin/env bash
# .git/hooks/post-merge
if git diff-tree -r --name-only --no-commit-id ORIG_HEAD HEAD | grep -q 'composer.lock'; then
echo "NOTICE: composer.lock has changed. Running composer check-platform-reqs..."
composer validate --no-check-all --strict || exit 1
fi
A post-merge git hook alerting developers when composer.lock changes eliminates dozens of wasted hours chasing ghost bugs caused by stale vendor directories.