Are we sure the signal list is finite?

@lyrixx I tried this snippet:

<?php

function sig_handler($signo)
{
     switch ($signo) {
         default:
     }
}

echo "Installing signal handler";

// setup signal handlers
pcntl_signal(66,  "sig_handler");

And here is the result:

Installing signal handlerPHP Fatal error:  Uncaught ValueError: pcntl_signal(): Argument #1 ($signal) must be less than 65 in /home/alex/signals.php:13
Stack trace:
#0 /home/alex/signals.php(13): pcntl_signal()
#1 {main}
  thrown in /home/alex/signals.php on line 15

So we should at least check that the signal number is lower than 65.
Checking that the given signal is defined in the extension comes from this comment from Nicolas: #49750 (comment). What do you think?

I think we should not enforce something that PHP allow. So 👍 with checking only if the number is lower than 65

I updated the SignalRegistry to check if the signal code is less than 32. Indeed, pcntl_signal_get_handler() in SignalRegistry if the signal code is above 31.

I also added a few tests for SignalRegistry.

Fatal error: Uncaught ValueError: pcntl_signal(): Argument #1 ($signal) must be less than 65 in /home/alex/signals.php:13

So, there is no need to add code to handle this, since the engine already has an appropriate behavior for invalid signals, isn't it?

less code == less bug. I agree with @nicolas-grekas