From 0afe87d7fb72063a04b3a010aece6efed283a062 Mon Sep 17 00:00:00 2001
From: Tony Brix <tony@brix.ninja>
Date: Thu, 7 Nov 2024 10:23:40 -0700
Subject: [PATCH] fix: fix del with escaped tilde (#3517)

* fix: fix del with escaped tilde

* use rules to check for unescaped tilde

* add tests with spaces
---
 src/rules.ts                          |  2 +-
 test/specs/new/escape_within_del.html |  6 ++++++
 test/specs/new/escape_within_del.md   | 11 +++++++++++
 3 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 test/specs/new/escape_within_del.html
 create mode 100644 test/specs/new/escape_within_del.md

diff --git a/src/rules.ts b/src/rules.ts
index 0dd0f84770..d132f8706b 100644
--- a/src/rules.ts
+++ b/src/rules.ts
@@ -301,7 +301,7 @@ const inlineGfm: Record<InlineKeys, RegExp> = {
     .replace('email', /[A-Za-z0-9._+-]+(@)[a-zA-Z0-9-_]+(?:\.[a-zA-Z0-9-_]*[a-zA-Z0-9])+(?![-_])/)
     .getRegex(),
   _backpedal: /(?:[^?!.,:;*_'"~()&]+|\([^)]*\)|&(?![a-zA-Z0-9]+;$)|[?!.,:;*_'"~)]+(?!$))+/,
-  del: /^(~~?)(?=[^\s~])([\s\S]*?[^\s~])\1(?=[^~]|$)/,
+  del: /^(~~?)(?=[^\s~])((?:\\.|[^\\])*?(?:\\.|[^\s~\\]))\1(?=[^~]|$)/,
   text: /^([`~]+|[^`~])(?:(?= {2,}\n)|(?=[a-zA-Z0-9.!#$%&'*+\/=?_`{\|}~-]+@)|[\s\S]*?(?:(?=[\\<!\[`*~_]|\b_|https?:\/\/|ftp:\/\/|www\.|$)|[^ ](?= {2,}\n)|[^a-zA-Z0-9.!#$%&'*+\/=?_`{\|}~-](?=[a-zA-Z0-9.!#$%&'*+\/=?_`{\|}~-]+@)))/,
 };
 
diff --git a/test/specs/new/escape_within_del.html b/test/specs/new/escape_within_del.html
new file mode 100644
index 0000000000..13132c7ea9
--- /dev/null
+++ b/test/specs/new/escape_within_del.html
@@ -0,0 +1,6 @@
+<p><del>\</del></p>
+<p>~\~</p>
+<p><del>~</del></p>
+<p>~\~~</p>
+<p>~~ ~</p>
+<p>~ ~~</p>
diff --git a/test/specs/new/escape_within_del.md b/test/specs/new/escape_within_del.md
new file mode 100644
index 0000000000..0421e75dad
--- /dev/null
+++ b/test/specs/new/escape_within_del.md
@@ -0,0 +1,11 @@
+~\\~
+
+~\\\~
+
+~\~~
+
+~\\~~
+
+~\~ ~
+
+~ \~~