[8.x] Fix multiple dots for digits_between rule

[driesvints]

This makes the digits_between rule a bit more strict by validating for multiple dots in a number (2.2.3, 2..3, ...).

Fixes #42326

[taai]

Possibilities to consider (for example, digits_between:1,10):

• single dot
• dot at the end (some may argue that it is valid, not me)
• dot at the beginning (some may argue that it is valid, not me)

[driesvints]

@taai ah the single dot is a good remark. Added a fix and test for that. The other two examples are indeed valid imo: https://3v4l.org/iDrQh

[taai]

• I suggest using substr_count($value, '.') to count the dots
• Why to convert/cast the value to string so many times?
• What if the value is not a string and is not a number, but is an array?
• I suggest doing simple, lightweight stuff (comparison operations) before doing hard stuff (like regex)
• I suggest using ctype_digit() which is significantly faster than regex

⚠️ N.B. Should also allow dots in validation rule digits – for consistency...

My solution:

public function validateDigitsBetween($attribute, $value, $parameters)
{
    $this->requireParameterCount(2, $parameters, 'digits_between');

    // make sure that the value is a number or a numeric string
    if (!is_numeric($value)) {
        return false;
    }

    if (is_string($value)) {
        // make sure that the value is not a dot and does not contain more than single dot
        if ($value === '.' || substr_count($value, '.') > 1) {
            return false;
        }
    } else {
        $value = strval($value);
    }

    $length = strlen($value);

    return $length >= $parameters[0] && $length <= $parameters[1]
        && ctype_digit(str_replace('.', '', $value));
}

public function validateDigits($attribute, $value, $parameters)
{
    $this->requireParameterCount(1, $parameters, 'digits');

    // make sure that the value is a number or a numeric string
    if (!is_numeric($value)) {
        return false;
    }

    if (is_string($value)) {
        // make sure that the value is not a dot and does not contain more than single dot
        if ($value === '.' || substr_count($value, '.') > 1) {
            return false;
        }
    } else {
        $value = strval($value);
    }

    return strlen($value) == $parameters[0]
        && ctype_digit(str_replace('.', '', $value));
}