From 859933d1803ff73ffa85443916b5cb4453c049c8 Mon Sep 17 00:00:00 2001
From: Colin O'Dell <colinodell@gmail.com>
Date: Sun, 25 Mar 2018 20:29:17 -0400
Subject: [PATCH 1/2] Don't allow escaped spaces in link destination.

See commonmark/CommonMark#493 and commonmark/commonmark.js@f0da145
---
 src/Inline/Parser/EscapableParser.php |  4 +---
 src/Util/LinkParserHelper.php         |  2 +-
 src/Util/RegexHelper.php              | 14 ++++++++++++++
 tests/unit/Util/RegexHelperTest.php   |  7 +++++++
 4 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/Inline/Parser/EscapableParser.php b/src/Inline/Parser/EscapableParser.php
index bfd8802f07..3f18b04e6e 100644
--- a/src/Inline/Parser/EscapableParser.php
+++ b/src/Inline/Parser/EscapableParser.php
@@ -48,9 +48,7 @@ public function parse(InlineParserContext $inlineContext)
             $inlineContext->getContainer()->appendChild(new Newline(Newline::HARDBREAK));
 
             return true;
-        } elseif ($nextChar !== null &&
-            preg_match('/' . RegexHelper::PARTIAL_ESCAPABLE . '/', $nextChar)
-        ) {
+        } elseif (RegexHelper::isEscapable($nextChar)) {
             $cursor->advanceBy(2);
             $inlineContext->getContainer()->appendChild(new Text($nextChar));
 
diff --git a/src/Util/LinkParserHelper.php b/src/Util/LinkParserHelper.php
index 116a921e5e..36f9a6bea1 100644
--- a/src/Util/LinkParserHelper.php
+++ b/src/Util/LinkParserHelper.php
@@ -37,7 +37,7 @@ public static function parseLinkDestination(Cursor $cursor)
         $oldState = $cursor->saveState();
         $openParens = 0;
         while (($c = $cursor->getCharacter()) !== null) {
-            if ($c === '\\') {
+            if ($c === '\\' && RegexHelper::isEscapable($cursor->peek())) {
                 $cursor->advanceBy(2);
             } elseif ($c === '(') {
                 $cursor->advance();
diff --git a/src/Util/RegexHelper.php b/src/Util/RegexHelper.php
index 4a8ea4b81f..43e2a738a7 100644
--- a/src/Util/RegexHelper.php
+++ b/src/Util/RegexHelper.php
@@ -174,6 +174,20 @@ public static function getInstance()
         return self::$instance;
     }
 
+    /**
+     * @param string|null $character
+     *
+     * @return bool
+     */
+    public static function isEscapable($character)
+    {
+        if ($character === null) {
+            return false;
+        }
+
+        return preg_match('/' . self::PARTIAL_ESCAPABLE . '/', $character) === 1;
+    }
+
     /**
      * Returns a partial regex
      *
diff --git a/tests/unit/Util/RegexHelperTest.php b/tests/unit/Util/RegexHelperTest.php
index 1d3950562a..cda5448106 100644
--- a/tests/unit/Util/RegexHelperTest.php
+++ b/tests/unit/Util/RegexHelperTest.php
@@ -269,6 +269,13 @@ public function testUnescape()
         $this->assertEquals('foo(and(bar))', RegexHelper::unescape('foo(and\\(bar\\))'));
     }
 
+    public function testIsEscapable()
+    {
+        $this->assertFalse(RegexHelper::isEscapable(null));
+        $this->assertFalse(RegexHelper::isEscapable('A'));
+        $this->assertTrue(RegexHelper::isEscapable('\\'));
+    }
+
     /**
      * @param $regex
      * @param $string

From f8d0d708093031d784da7f21dcd5800db474397c Mon Sep 17 00:00:00 2001
From: Colin O'Dell <colinodell@gmail.com>
Date: Sun, 25 Mar 2018 21:23:15 -0400
Subject: [PATCH 2/2] Prepare for 0.17.2 release

---
 CHANGELOG.md | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 677a2be1a5..84b14c53d9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,16 @@ Updates should follow the [Keep a CHANGELOG](http://keepachangelog.com/) princip
 
 ## [Unreleased][unreleased]
 
+## [0.17.2] - 2017-03-25
+
+### Added
+
+ - Added new `RegexHelper::isEscapable()` method
+
+### Fixed
+
+ - Fixed spec compliance bug where escaped spaces should not be allowed in link destinations
+
 ## [0.17.1] - 2017-03-18
 
 ### Added
@@ -615,7 +625,8 @@ An unused constant and static method were deprecated and will be removed in a fu
 ### Added
  - Initial commit (compatible with jgm/stmd:spec.txt @ 0275f34)
 
-[unreleased]: https://github.com/thephpleague/commonmark/compare/0.17.1...HEAD
+[unreleased]: https://github.com/thephpleague/commonmark/compare/0.17.2...HEAD
+[0.17.2]: https://github.com/thephpleague/commonmark/compare/0.17.1...0.17.2
 [0.17.1]: https://github.com/thephpleague/commonmark/compare/0.17.0...0.17.1
 [0.17.0]: https://github.com/thephpleague/commonmark/compare/0.16.0...0.17.0
 [0.16.0]: https://github.com/thephpleague/commonmark/compare/0.15.7...0.16.0