From 0f55cd5b266249de1dd914058e74a235c3ea02bf Mon Sep 17 00:00:00 2001
From: Aidan Woods <aidantwoods@gmail.com>
Date: Sun, 27 Jan 2019 20:53:11 +0000
Subject: [PATCH] Permit empty links

---
 src/Components/Inlines/Link.php | 4 ++--
 tests/commonmark/470-Links.html | 4 +---
 tests/commonmark/470-Links.md   | 6 +-----
 tests/commonmark/547-Links.html | 1 +
 tests/commonmark/547-Links.md   | 3 +++
 5 files changed, 8 insertions(+), 10 deletions(-)
 create mode 100644 tests/commonmark/547-Links.html
 create mode 100644 tests/commonmark/547-Links.md

diff --git a/src/Components/Inlines/Link.php b/src/Components/Inlines/Link.php
index af9c27c..9d14d2e 100644
--- a/src/Components/Inlines/Link.php
+++ b/src/Components/Inlines/Link.php
@@ -61,8 +61,8 @@ final class Link implements Inline
 
         $remainder = \substr($remainder, $width);
 
-        if (\preg_match('/^[(]\s*+((?:[^ ()]++|[(][^ )]+[)])++)(?:[ ]+("[^"]*+"|\'[^\']*+\'))?\s*+[)]/', $remainder, $matches)) {
-            $url = $matches[1];
+        if (\preg_match('/^[(]\s*+(?:((?:[^ ()]++|[(][^ )]+[)])++)(?:[ ]+("[^"]*+"|\'[^\']*+\'))?\s*+)?[)]/', $remainder, $matches)) {
+            $url = isset($matches[1]) ? $matches[1] : '';
             $title = isset($matches[2]) ? \substr($matches[2], 1, - 1) : null;
 
             $width += \strlen($matches[0]);
diff --git a/tests/commonmark/470-Links.html b/tests/commonmark/470-Links.html
index 4a3cb66..782298a 100644
--- a/tests/commonmark/470-Links.html
+++ b/tests/commonmark/470-Links.html
@@ -1,3 +1 @@
-<p><a href="#fragment">link</a></p>
-<p><a href="http://example.com#fragment">link</a></p>
-<p><a href="http://example.com?foo=3#frag">link</a></p>
\ No newline at end of file
+<p><a href="">link</a></p>
\ No newline at end of file
diff --git a/tests/commonmark/470-Links.md b/tests/commonmark/470-Links.md
index efea20f..b84d6c2 100644
--- a/tests/commonmark/470-Links.md
+++ b/tests/commonmark/470-Links.md
@@ -1,5 +1 @@
-[link](#fragment)
-
-[link](http://example.com#fragment)
-
-[link](http://example.com?foo=3#frag)
\ No newline at end of file
+[link]()
\ No newline at end of file
diff --git a/tests/commonmark/547-Links.html b/tests/commonmark/547-Links.html
new file mode 100644
index 0000000..4134c8f
--- /dev/null
+++ b/tests/commonmark/547-Links.html
@@ -0,0 +1 @@
+<p><a href="">foo</a></p>
\ No newline at end of file
diff --git a/tests/commonmark/547-Links.md b/tests/commonmark/547-Links.md
new file mode 100644
index 0000000..0979681
--- /dev/null
+++ b/tests/commonmark/547-Links.md
@@ -0,0 +1,3 @@
+[foo]()
+
+[foo]: /url1
\ No newline at end of file