The infinite recursion bug in print_r still appears to be there as can be demonstrated by this little script:

<?php
    $tmp = array();
    $tmp2 = array();
    $tmp3 = array();
    $tmp[] =& $tmp2;
    $tmp[] =& $tmp3;
    $tmp2[] =& $tmp;
    $tmp2[] =& $tmp3;
    $tmp3[] =& $tmp;
    $tmp3[] =& $tmp2;
    print_r($tmp);
?>

I have looked into the code and I believe the bug lies in zend_print_zval_r_ex().

                        if (++expr->value.ht->nApplyCount>1) {
                                ZEND_PUTS(" *RECURSION*");
                                expr->value.ht->nApplyCount=0;
                                return;
                        }

seems to be wrong.  I believe it should read:

                        if (++expr->value.ht->nApplyCount>1) {
                                ZEND_PUTS(" *RECURSION*");
                                expr->value.ht->nApplyCount--;
                                return;
                        }

and the same change should be made lower down for the objects.  The current code spots the recursion because the counter is 1 and increased to 2, but then effectively hides that state from anything else by resetting the counter to 0.