require closing fence to be on a new line (fix markedjs#1058), while …

…still allowing empty code blocks

lib/marked.js

@@ -91,7 +91,7 @@ block.normal = merge({}, block);
  */
 
 block.gfm = merge({}, block.normal, {
-  fences: /^ *(`{3,}|~{3,})[ \.]*(\S+)? *\n([\s\S]*?)\n? *\1 *(?:\n+|$)/,
+  fences: /^ *(`{3,}|~{3,})[ \.]*(\S+)? *\n(?:|([\s\S]*?)\n) *\1 *(?:\n+|$)/,
   paragraph: /^/,
   heading: /^ *(#{1,6}) +([^\n]+?) *#* *(?:\n+|$)/
 });

test/new/gfm_code.html

@@ -14,3 +14,8 @@
 
 
 </code></pre>
+
+<p>Closing fences must lay on a new line:</p>
+<pre><code>hello()
+^```
+&quot;this should still be in the code block!&quot;</code></pre>

test/new/gfm_code.md

@@ -33,3 +33,11 @@ ciao
 
 
 ```
+
+Closing fences must lay on a new line:
+
+```
+hello()
+^```
+"this should still be in the code block!"
+```