diff --git a/degesch.c b/degesch.c
index 7b8494f..57b1bf7 100644
--- a/degesch.c
+++ b/degesch.c
@@ -9347,13 +9347,15 @@ static bool
 handle_command_set_add
 	(struct config_item *item, const char *value, struct error **e)
 {
-	bool result = false;
 	struct str_vector items;
 	str_vector_init (&items);
-	cstr_split (item->value.string.str, ",", &items);
+	if (item->type != CONFIG_ITEM_NULL)
+		cstr_split (item->value.string.str, ",", &items);
 	if (items.len == 1 && !*items.vector[0])
 		str_vector_reset (&items);
 
+	// FIXME: handle multiple items properly
+	bool result = false;
 	if (str_vector_find (&items, value) != -1)
 		error_set (e, "already present in the array: %s", value);
 	else
@@ -9370,13 +9372,15 @@ static bool
 handle_command_set_remove
 	(struct config_item *item, const char *value, struct error **e)
 {
-	bool result = false;
 	struct str_vector items;
 	str_vector_init (&items);
-	cstr_split (item->value.string.str, ",", &items);
+	if (item->type != CONFIG_ITEM_NULL)
+		cstr_split (item->value.string.str, ",", &items);
 	if (items.len == 1 && !*items.vector[0])
 		str_vector_reset (&items);
 
+	// FIXME: handle multiple items properly
+	bool result = false;
 	ssize_t i = str_vector_find (&items, value);
 	if (i == -1)
 		error_set (e, "not present in the array: %s", value);
@@ -9401,15 +9405,14 @@ handle_command_set_assign_item (struct app_context *ctx,
 	struct error *e = NULL;
 	if (!item->schema)
 		error_set (&e, "option not recognized");
-	else if ((add | remove) && item->type != CONFIG_ITEM_STRING_ARRAY)
-		// FIXME: it can also be null, which makes this message confusing
+	else if (!add && !remove)
+		config_item_set_from (item, config_item_clone (new_), &e);
+	else if (item->schema->type != CONFIG_ITEM_STRING_ARRAY)
 		error_set (&e, "not a string array");
 	else if (add)
 		handle_command_set_add (item, new_->value.string.str, &e);
 	else if (remove)
 		handle_command_set_remove (item, new_->value.string.str, &e);
-	else
-		config_item_set_from (item, config_item_clone (new_), &e);
 
 	if (e)
 	{