The functions are not handling null arguments the same way as the php extension.
Argument validation raises warnings for null arguments and returns incorrect null value as function result.

print_r(
    array(
        'bcadd(1, 1)' => bcadd(1, 1),
        'bcadd(null, 1)' => bcadd(null, 1),
        'bcadd(1, null)' => bcadd(1, null),
    )
);

Result with php bcmath:

Array
(
    [bcadd(1, 1)] => 2
    [bcadd(null, 1)] => 1
    [bcadd(1, null)] => 1
)

Result with phpseclib/bcmath_compat:

Warning: bcadd() expects parameter 0 to be integer, NULL given in vendor\phpseclib\bcmath_compat\src\BCMath.php on line 418

Warning: bcadd() expects parameter 1 to be integer, NULL given in vendor\phpseclib\bcmath_compat\src\BCMath.php on line 418

Array
(
    [bcadd(1, 1)] => 2
    [bcadd(null, 1)] =>
    [bcadd(1, null)] =>
)

Argument validation should accept null.
Since before method calling non numeric arguments are casted to 0, it is safe to accept null at argument validation.

Are there any plans to push a new release to Packagist? The current release 2.0.1 is four years old and is throwing deprecation errors in PHP 8.2.

The problem line is https://github.com/phpseclib/bcmath_compat/blob/29bbf07a7039ff65ce7daa44502ba34baf1512ec/src/BCMath.php#L486C1-L486C77 - 2.0.1 makes a deprecated call to self::class.

This appears to have been fixed on all three branches, but nothing has been released.

The polyfill seems to not work with PHP 8.3 and gives a error that module is not present, when I switch back to PHP 8.1 it works as expected

During an Heroku deployment i get this error :

Your requirements could not be resolved to an installable set of packages.

Problem 1
- don't install phpseclib/bcmath_compat 1.0.3|don't install php 7.3.13
- composer.json/composer.lock requires php 7.3.* -> satisfiable by php[7.3.13].
- Installation request for phpseclib/bcmath_compat 1.0.3 -> satisfiable by phpseclib/bcmath_compat[1.0.3].

The phpseclib/bcmath_compat package is an indirect dependency of laravel/framework via moontoast/math

The exception ArgumentCountError gives wrong given parameter length.
When a function is called with wrong amounts of parameters, e.g. static BCMath::scale(4,2,3), in the magic static function __callStatic($name, $arguments) line 373 throws an error. That is ok, but the func_num_args() used - only returns the number of parameters of the called function and is always 2 in that case. That should be the amount of $arguments (array).
You are probably wondering why I came up with this? My editor shows me an error that the parameters for the __callStatic() magic function should always be the amount of 2.
I fixed it with PR #6