There is an undocumented case where the output of an internal function is different in PHP 5.2 vs PHP 5.3 when you pass it an invalid argument.
For example, strlen returns different values and warnings/notices when attempting to pass it an array.
In the above patch, I see that strlen and other functions(method_exists, property_exists, function_exists, strcmp, strncmp, strcasecmp, strncasecmp, defined, is_a_impl) were not using zend_parse_parameters to get the arguments. This was preventing the standard validations and warnings from running for that function. Also, those functions were incorrectly casting the arguments to string with convert_to_string_ex. That is why, in PHP 5.2, strlen() of array() is int(5); because, casting array() to string returns "Array".
Now, in PHP 5.3, those functions will no longer coerce the arguments to strings, will return NULL, and will issue a warning when invalid arguments have been provided. Thanks stas.