A practical guide to checking defined constants in PHP safely, including a better current snippet for WordPress and server-side debugging with DISALLOW_FILE_EDIT.
A practical guide to debugging PHP with current error reporting, logging, variable inspection, and Xdebug recommendations for development, staging, and production environments.
A safer, current guide to debugging WordPress on a live site: log errors without exposing them to visitors, use WP-CLI for isolation, and avoid outdated cache assumptions.