From 2290e109c5c6b0391f4416adc9c0b0a9b9923326 Mon Sep 17 00:00:00 2001
From: Alex Kocharin <alex@kocharin.ru>
Date: Tue, 24 Nov 2020 14:43:32 +0300
Subject: [PATCH] Disallow escaped spaces inside link destination

---
 CHANGELOG.md                                    | 1 +
 lib/helpers/parse_link_destination.js           | 1 +
 test/fixtures/markdown-it/commonmark_extras.txt | 8 ++++++++
 3 files changed, 10 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b45a881e7..45e4e5c03 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 - `[](<foo<bar>)` is no longer a valid link.
 - `[](url (xxx())` is no longer a valid link.
+- `[](url\ xxx)` is no longer a valid link.
 - Fix performance issues when parsing links, #732, #734.
 - Fix performance issues when parsing backticks, #733.
 - Fix performance issues when parsing emphases, #735.
diff --git a/lib/helpers/parse_link_destination.js b/lib/helpers/parse_link_destination.js
index 6c1423c6a..637f1f42e 100644
--- a/lib/helpers/parse_link_destination.js
+++ b/lib/helpers/parse_link_destination.js
@@ -53,6 +53,7 @@ module.exports = function parseLinkDestination(str, pos, max) {
     if (code < 0x20 || code === 0x7F) { break; }
 
     if (code === 0x5C /* \ */ && pos + 1 < max) {
+      if (str.charCodeAt(pos + 1) === 0x20) { break; }
       pos += 2;
       continue;
     }
diff --git a/test/fixtures/markdown-it/commonmark_extras.txt b/test/fixtures/markdown-it/commonmark_extras.txt
index 75a9fecb0..56b4a31bc 100644
--- a/test/fixtures/markdown-it/commonmark_extras.txt
+++ b/test/fixtures/markdown-it/commonmark_extras.txt
@@ -278,6 +278,14 @@ Link title cannot contain '(' when opened with it
 .
 
 
+Escaped space is not allowed in link destination, commonmark/CommonMark#493.
+.
+[link](a\ b)
+.
+<p>[link](a\ b)</p>
+.
+
+
 Coverage. Directive can terminate paragraph.
 .
 a