Php, how to cast/convert Exception to RuntimeException?

there is a code snippet:

function test()
{
    if (mt_rand(1,4) === 2)
    {
        throw new \Exception('exception');
    }
}

try
{
    test();
}
catch(\Exception $e)
{
    //throw $e;
    throw new \RuntimeException($e->getMessage());
}

this is trivial example of course, but I there is a test() function which is used in two project. One of them it may throw an exception and is handled. But in another I must not handle it but let it happen and I can handle the stack.

But if I use the throw new \RuntimeException($e->getMessage()); form, I wont get the true stack trace, I wont know if that happened in test() function.

But if I use the throw $e; form, its an \Exception but not a RuntimeException.

Normally an Exception is a usual exception which must be caught. But RuntimeException must not be caught since it can be resolved in code. So how to make that exception to RuntimeException?

Remember that RuntimeException has a $previous argument available in its constructor where you can supply the original exception:

try {
    test();
} catch (\Exception $e) {
    throw new \RuntimeException($e->getMessage(), $e->getCode(), $e);
}

You can also omit the code, or even the message, should you not need it:

throw new \RuntimeException($e->getMessage(), previous: $e);
throw new \RuntimeException(previous: $e);

The stack trace can be retrieved from .getTrace() or .getTraceAsString(), depending on the format wanted, and previous exception is available through its getter, so you can get the whole history with:

try {
    // ....
} catch (\RuntimeException $e) {
    echo 'Exception caught', PHP_EOL;
    while ($e) {
        echo 'Trace for ', get_class($e), "\n";
        print_r($e->getTrace());
        $e = $e->getPrevious();
    }
}

Demo