fix need to apply to LDAP_MOD_ADD only

Author: devnexen

ext/ldap/ldap.c

@@ -2339,13 +2339,13 @@ static void php_ldap_do_modify(INTERNAL_FUNCTION_PARAMETERS, int oper, bool ext)
 			SEPARATE_ARRAY(attribute_values);
 			uint32_t num_values = zend_hash_num_elements(Z_ARRVAL_P(attribute_values));
 			if (num_values == 0) {
-				if (UNEXPECTED(is_full_add)) {
+				if (UNEXPECTED(oper == LDAP_MOD_ADD)) {
 					zend_argument_value_error(3, "attribute \"%s\" must be a non-empty list of attribute values", ZSTR_VAL(attribute));
 					RETVAL_FALSE;
 					goto cleanup;
 				}
-				/* When we modify, we means we delete the attribute */
-				attribute_index ++;
+				/* When we modify, we mean we delete the attribute */
+				attribute_index++;
 				continue;
 			}
 			if (!php_ldap_is_numerically_indexed_array(Z_ARRVAL_P(attribute_values))) {