PHP 8 cost me a new customer. I can see in the logs where they tried to subscribe. But they hit PHP 8’s insidious error, Warning: Undefined array key….

For better or worse, checking an array value using a possibly-non-existent key was a common pattern in PHP code. You could do it in an if statement and count on the result being truthy or falsey. Yeah I know, I know. But still.

This change makes ton of existing code problematic.

Here’s the best fix that I know of: mattwatson.org/blog/20230716-l