From 6b4f70d6d45c034af45d3c6fbc0021dda97004d3 Mon Sep 17 00:00:00 2001
From: yuxi-liu-wired <33951560+yuxi-liu-wired@users.noreply.github.com>
Date: Sun, 4 Oct 2026 21:38:00 +0000
Subject: [PATCH] Let an unclosed comment skip only later comment scans

When `<!--` has no closing `-->` before the end of the input,
FLAG_SKIP_HTML_COMMENT is set so later `<!--` don't rescan. The flag was
checked before any `<!` construct, so it also stopped declarations and
CDATA sections after the unclosed comment:

    a <!-- x <!B> <![CDATA[y]]> c

rendered `<!B>` and the CDATA section as text. Check the flag only where
the comment scan runs.
---
 src/inlines.c       | 4 ++--
 test/regression.txt | 8 ++++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/inlines.c b/src/inlines.c
index bf765eab5..f9f70e703 100644
--- a/src/inlines.c
+++ b/src/inlines.c
@@ -931,7 +931,7 @@ static cmark_node *handle_pointy_brace(subject *subj, int options) {
   // finally, try to match an html tag
   if (subj->pos + 2 <= subj->input.len) {
     int c = subj->input.data[subj->pos];
-    if (c == '!' && (subj->flags & FLAG_SKIP_HTML_COMMENT) == 0) {
+    if (c == '!') {
       c = subj->input.data[subj->pos+1];
       if (c == '-' && subj->input.data[subj->pos+2] == '-') {
 	if (subj->pos + 3 < subj->input.len &&
@@ -941,7 +941,7 @@ static cmark_node *handle_pointy_brace(subject *subj, int options) {
                    subj->input.data[subj->pos+3] == '-' &&
                    subj->input.data[subj->pos+4] == '>') {
           matchlen = 5;
-        } else {
+        } else if ((subj->flags & FLAG_SKIP_HTML_COMMENT) == 0) {
           matchlen = scan_html_comment(&subj->input, subj->pos + 1);
           if (matchlen > 0) {
             matchlen += 1; // prefix "<"
diff --git a/test/regression.txt b/test/regression.txt
index 1426617ab..c0571985d 100644
--- a/test/regression.txt
+++ b/test/regression.txt
@@ -212,6 +212,14 @@ x <!A>
 <p>x <!A></p>
 ````````````````````````````````
 
+An unclosed HTML comment must not stop later declarations and CDATA
+sections from being recognized as raw HTML.
+```````````````````````````````` example
+a <!-- x <!B> <![CDATA[y]]> c
+.
+<p>a &lt;!-- x <!B> <![CDATA[y]]> c</p>
+````````````````````````````````
+
 An underscore that is not part of a delimiter should not prevent another
 pair of underscores from forming part of their own.
 ```````````````````````````````` example