patch 8.2.1821: Vim9: concatenating to a NULL list doesn't work
Problem: Vim9: concatenating to a NULL list doesn't work.
Solution: Handle a NULL list like an empty list. (closes #7064)
diff --git a/src/list.c b/src/list.c
index e86ec86..59c614f 100644
--- a/src/list.c
+++ b/src/list.c
@@ -824,7 +824,7 @@
}
/*
- * Extend "l1" with "l2".
+ * Extend "l1" with "l2". "l1" must not be NULL.
* If "bef" is NULL append at the end, otherwise insert before this item.
* Returns FAIL when out of memory.
*/
@@ -832,8 +832,13 @@
list_extend(list_T *l1, list_T *l2, listitem_T *bef)
{
listitem_T *item;
- int todo = l2->lv_len;
+ int todo;
+ // NULL list is equivalent to an empty list: nothing to do.
+ if (l2 == NULL || l2->lv_len == 0)
+ return OK;
+
+ todo = l2->lv_len;
CHECK_LIST_MATERIALIZE(l1);
CHECK_LIST_MATERIALIZE(l2);
@@ -854,15 +859,17 @@
{
list_T *l;
- if (l1 == NULL || l2 == NULL)
- return FAIL;
-
// make a copy of the first list.
- l = list_copy(l1, FALSE, 0);
+ if (l1 == NULL)
+ l = list_alloc();
+ else
+ l = list_copy(l1, FALSE, 0);
if (l == NULL)
return FAIL;
tv->v_type = VAR_LIST;
tv->vval.v_list = l;
+ if (l1 == NULL)
+ ++l->lv_refcount;
// append all items from the second list
return list_extend(l, l2, NULL);