From 92dcae9723260a386bb5162edb9c015fd8fd669b Mon Sep 17 00:00:00 2001
From: dodmi <4572946+dodmi@users.noreply.github.com>
Date: Sat, 4 Jan 2025 12:14:42 +0100
Subject: [PATCH] 2.x: Backport: Allow up to 3 levels of nested comments in ARH
 (#479)

Backport of #466.
---
 modules/rfcParser.jsm.js | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/modules/rfcParser.jsm.js b/modules/rfcParser.jsm.js
index 5566f45d..2addfcff 100644
--- a/modules/rfcParser.jsm.js
+++ b/modules/rfcParser.jsm.js
@@ -59,8 +59,13 @@ let rfcParser = (function() {
 	RfcParserStd.FWS_op = `${RfcParserStd.FWS}?`;
 	// Note: this is incomplete (obs-ctext is missing)
 	RfcParserStd.ctext = "[!-'*-[\\]-~]";
-	// Note: this is incomplete (comment is missing)
-	RfcParserStd.ccontent = `(?:${RfcParserStd.ctext}|${RfcParserStd.quoted_pair})`;
+	// Note: There is a recursion in ccontent/comment, which is not supported by the RegExp in JavaScript.
+	// We currently unroll it to support a depth of up to 3 comments.
+	RfcParserStd.ccontent_2 = `(?:${RfcParserStd.ctext}|${RfcParserStd.quoted_pair})`;
+	RfcParserStd.comment_2 = `\\((?:${RfcParserStd.FWS_op}${RfcParserStd.ccontent_2})*${RfcParserStd.FWS_op}\\)`;
+	RfcParserStd.ccontent_1 = `(?:${RfcParserStd.ctext}|${RfcParserStd.quoted_pair}|${RfcParserStd.comment_2})`;
+	RfcParserStd.comment_1 = `\\((?:${RfcParserStd.FWS_op}${RfcParserStd.ccontent_1})*${RfcParserStd.FWS_op}\\)`;
+	RfcParserStd.ccontent = `(?:${RfcParserStd.ctext}|${RfcParserStd.quoted_pair}|${RfcParserStd.comment_1})`;
 	RfcParserStd.comment = `\\((?:${RfcParserStd.FWS_op}${RfcParserStd.ccontent})*${RfcParserStd.FWS_op}\\)`;
 	RfcParserStd.CFWS = `(?:(?:(?:${RfcParserStd.FWS_op}${RfcParserStd.comment})+${RfcParserStd.FWS_op})|${RfcParserStd.FWS})`;
 	// Note: helper only, not part of the RFC