From 2dc33d578c6f0e6607ba3057f84234e312a9b169 Mon Sep 17 00:00:00 2001
From: Shuanglei Tao <tsl0922@gmail.com>
Date: Tue, 6 Sep 2016 14:15:36 +0800
Subject: [PATCH] GFM: be more clever on parsing fenced codeblock

---
 lib/kramdown/parser/gfm.rb                  |  4 ++--
 test/testcases_gfm/codeblock_fenced.html    | 20 ++++++++++++++++++++
 test/testcases_gfm/codeblock_fenced.options |  1 +
 test/testcases_gfm/codeblock_fenced.text    | 21 +++++++++++++++++++++
 4 files changed, 44 insertions(+), 2 deletions(-)
 create mode 100644 test/testcases_gfm/codeblock_fenced.html
 create mode 100644 test/testcases_gfm/codeblock_fenced.options
 create mode 100644 test/testcases_gfm/codeblock_fenced.text

diff --git a/lib/kramdown/parser/gfm.rb b/lib/kramdown/parser/gfm.rb
index 743c5ddd..1b0ab9f1 100644
--- a/lib/kramdown/parser/gfm.rb
+++ b/lib/kramdown/parser/gfm.rb
@@ -85,8 +85,8 @@ def parse_atx_header_gfm_quirk
         true
       end
 
-      FENCED_CODEBLOCK_START = /^[~`]{3,}/
-      FENCED_CODEBLOCK_MATCH = /^(([~`]){3,})\s*?((\S+?)(?:\?\S*)?)?\s*?\n(.*?)^\1\2*\s*?\n/m
+      FENCED_CODEBLOCK_START = /^[ ]{0,3}[~`]{3,}/
+      FENCED_CODEBLOCK_MATCH = /^[ ]{0,3}(([~`]){3,})\s*?((\S+?)(?:\?\S*)?)?\s*?\n(.*?)^[ ]{0,3}\1\2*\s*?\n/m
       define_parser(:codeblock_fenced_gfm, FENCED_CODEBLOCK_START, nil, 'parse_codeblock_fenced')
 
       STRIKETHROUGH_DELIM = /~~/
diff --git a/test/testcases_gfm/codeblock_fenced.html b/test/testcases_gfm/codeblock_fenced.html
new file mode 100644
index 00000000..0bdefdc3
--- /dev/null
+++ b/test/testcases_gfm/codeblock_fenced.html
@@ -0,0 +1,20 @@
+<p>normal</p>
+
+<pre><code class="language-ruby">require 'kramdown'
+
+Kramdown::Document.new(text).to_html
+</code></pre>
+
+<p>indent with tab</p>
+
+<pre><code>```ruby
+require 'kramdown'
+
+Kramdown::Document.new(text).to_html
+```
+</code></pre>
+
+<p>indent with 2 spaces</p>
+
+<pre><code class="language-js">  console.log("hello");
+</code></pre>
diff --git a/test/testcases_gfm/codeblock_fenced.options b/test/testcases_gfm/codeblock_fenced.options
new file mode 100644
index 00000000..72e9bc1e
--- /dev/null
+++ b/test/testcases_gfm/codeblock_fenced.options
@@ -0,0 +1 @@
+:enable_coderay: false
diff --git a/test/testcases_gfm/codeblock_fenced.text b/test/testcases_gfm/codeblock_fenced.text
new file mode 100644
index 00000000..5e3e192c
--- /dev/null
+++ b/test/testcases_gfm/codeblock_fenced.text
@@ -0,0 +1,21 @@
+normal
+
+```ruby
+require 'kramdown'
+
+Kramdown::Document.new(text).to_html
+```
+
+indent with tab
+
+	```ruby
+	require 'kramdown'
+
+	Kramdown::Document.new(text).to_html
+	```
+
+indent with 2 spaces
+
+  ```js
+  console.log("hello");
+  ```