https://github.com/commonmark/cmark/commit/a739d4911b5fa5586679b8e55999719cc910d26b
From: John MacFarlane <jgm@berkeley.edu>
Date: Wed, 13 Mar 2024 14:31:28 -0700
Subject: [PATCH] Flag root node as open...

in `cmark_parser_new_with_mem_into_root`. Closes #532.
--- a/src/blocks.c
+++ b/src/blocks.c
@@ -98,6 +98,8 @@ cmark_parser *cmark_parser_new_with_mem_into_root(int options, cmark_mem *mem, c
   cmark_strbuf_init(mem, &parser->linebuf, 0);
   cmark_strbuf_init(mem, &parser->content, 0);
 
+  root->flags = CMARK_NODE__OPEN;
+
   parser->refmap = cmark_reference_map_new(mem);
   parser->root = root;
   parser->current = root;