Disallow escaped spaces inside link destination

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.

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;
     }

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