A better fix for #55817 (thanks to bjori)

diff --git a/ext/mbstring/mbstring.c b/ext/mbstring/mbstring.c
index 513013b8b6cecc0490f258b96088d483613e7708..8111e6127fc2238d5ce43211b26e4ce08fe2bff2 100644 (file)
--- a/ext/mbstring/mbstring.c
+++ b/ext/mbstring/mbstring.c
@@ -3183,7 +3183,7 @@ PHP_FUNCTION(mb_detect_encoding)
        /* make encoding list */
        list = NULL;
        size = 0;
-       if (ZEND_NUM_ARGS() >= 2) {
+       if (ZEND_NUM_ARGS() >= 2 && !ZVAL_IS_NULL(encoding_list)) {
                switch (Z_TYPE_P(encoding_list)) {
                case IS_ARRAY:
                        if (FAILURE == php_mb_parse_encoding_array(encoding_list, &list, &size, 0 TSRMLS_CC)) {