SOLVED: new Unserialize_Parser class throws exceptions on NULL values

Question

I had a real problem with SUPEE-8788 related to the decision to replace PHP's unserialize() function with the new Unserialize_Parser. The problem is that the Gene_Braintree payment extension sets NULL values in the additional_data array saved in the payment quote. This was causing the exception "Unsupported data type N" to be thrown at checkout.

Here's how I solved this:

1. Added const TYPE_NULL = 'N'; to lib/Unserialize/Parser.php
2. Created a new class Unserialize_Reader_Null (full code below)
3. Added a case to the switch statement in lib/Unserialize/Reader/ArrValue.php to check for my new TYPE_NULL character and instantiate a new Unserialize_Reader_Null() if it is found

New file lib/Unserialize/Reader/Null.php:

<?php
class Unserialize_Reader_Null
{
    /**
     * @var int
     */
    protected $_status;

    /**
     * @var string|int
     */
    protected $_value;

    const READING_VALUE = 1;

    /**
     * @param string $char
     * @param string $prevChar
     * @return int|null
     */
    public function read($char, $prevChar)
    {
        if ($char == Unserialize_Parser::TYPE_NULL) {
            return null;
        }
        else if ($char == Unserialize_Parser::SYMBOL_SEMICOLON) {
            return '';
        }
    }
}

Answer 1

This bug was fixed in SUPEE-8788 V2, I reckon you should install that version to ensure you did not miss anything else ;)