Handle ts_node_type return NULL (bug#78938)

* src/treesit.c (treesit_traverse_match_predicate): Handle the
case when ts_node_type returns NULL.
(Ftreesit_node_type): Add some comment.

1 files changed, 11 insertions, 1 deletions

diff --git a/src/treesit.c b/src/treesit.c
index 7393404f7ea..e2986c186b8 100644
--- a/src/treesit.c
+++ b/src/treesit.c
@@ -2043,7 +2043,9 @@ If NODE is nil, return nil.  */)
   treesit_initialize ();
 
   TSNode treesit_node = XTS_NODE (node)->node;
-  /* ts_node_type could return NULL, see source code.  */
+  /* ts_node_type could return NULL, see source code (tree-sitter can't
+     find the string name of a node type by its id in its node name
+     obarray).  */
   const char *type = ts_node_type (treesit_node);
   return type == NULL ? Vtreesit_str_empty : build_string (type);
 }
@@ -3595,6 +3597,10 @@ treesit_traverse_match_predicate (TSTreeCursor *cursor, Lisp_Object pred,
   if (STRINGP (pred))
     {
       const char *type = ts_node_type (node);
+      /* ts_node_type returning NULL means something unexpected happend
+         in tree-sitter, in this case the only reasonable thing is to
+         not match anything.  */
+      if (type == NULL) return false;
       return fast_c_string_match (pred, type, strlen (type)) >= 0;
     }
   else if (FUNCTIONP (pred))
@@ -3632,6 +3638,10 @@ treesit_traverse_match_predicate (TSTreeCursor *cursor, Lisp_Object pred,
         {
           /* A bit of code duplication here, but should be fine.  */
           const char *type = ts_node_type (node);
+          /* ts_node_type returning NULL means something unexpected
+             happend in tree-sitter, in this case the only reasonable
+             thing is to not match anything  */
+          if (type == NULL) return false;
           if (!(fast_c_string_match (car, type, strlen (type)) >= 0))
             return false;