Don't allow insert_{before|after} root node

This can be changed if support for node lists is added to the public API.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/node.c b/src/node.c
index 8de46ea..8b107bc 100644
--- a/src/node.c
+++ b/src/node.c
@@ -436,7 +436,7 @@ cmark_node_unlink(cmark_node *node) {
 int
 cmark_node_insert_before(cmark_node *node, cmark_node *sibling)
 {
-	if (!S_can_contain(node->parent, sibling)) {
+	if (!node->parent || !S_can_contain(node->parent, sibling)) {
 		return 0;
 	}
 
@@ -467,7 +467,7 @@ cmark_node_insert_before(cmark_node *node, cmark_node *sibling)
 int
 cmark_node_insert_after(cmark_node *node, cmark_node *sibling)
 {
-	if (!S_can_contain(node->parent, sibling)) {
+	if (!node->parent || !S_can_contain(node->parent, sibling)) {
 		return 0;
 	}