From aa41a9ce700a1a39d13c189d0f769694bce603aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A9gis=20Hanol?= <regis@hanol.fr>
Date: Tue, 17 Mar 2015 17:27:16 +0100
Subject: [PATCH] FIX: remove empty lines but keep whitespace on first line in
 code blocks

---
 .../javascripts/discourse/dialects/dialect.js       | 13 ++++++++-----
 test/javascripts/lib/markdown-test.js.es6           |  2 +-
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/app/assets/javascripts/discourse/dialects/dialect.js b/app/assets/javascripts/discourse/dialects/dialect.js
index d5d785e2a38..9d0cbef8d7b 100644
--- a/app/assets/javascripts/discourse/dialects/dialect.js
+++ b/app/assets/javascripts/discourse/dialects/dialect.js
@@ -167,6 +167,11 @@ function outdent(t) {
   return t.replace(/^([ ]{4}|\t)/gm, "");
 }
 
+function removeEmptyLines(t) {
+  return t.replace(/^\n+/, "")
+          .replace(/\s+$/, "");
+}
+
 function hideBackslashEscapedCharacters(t) {
   return t.replace(/\\\\/g, "\u1E800")
           .replace(/\\`/g, "\u1E8001");
@@ -186,14 +191,14 @@ function hoistCodeBlocksAndSpans(text) {
   // <pre>...</pre> code blocks
   text = text.replace(/(^\n*|\n\n)<pre>([\s\S]*?)<\/pre>/ig, function(_, before, content) {
     var hash = md5(content);
-    hoisted[hash] = escape(showBackslashEscapedCharacters(content.trim()));
+    hoisted[hash] = escape(showBackslashEscapedCharacters(removeEmptyLines(content)));
     return before + "<pre>" + hash + "</pre>";
   });
 
   // fenced code blocks (AKA GitHub code blocks)
   text = text.replace(/(^\n*|\n\n)```([a-z0-9\-]*)\n([\s\S]*?)\n```/g, function(_, before, language, content) {
     var hash = md5(content);
-    hoisted[hash] = escape(showBackslashEscapedCharacters(content.trim()));
+    hoisted[hash] = escape(showBackslashEscapedCharacters(removeEmptyLines(content)));
     return before + "```" + language + "\n" + hash + "\n```";
   });
 
@@ -209,9 +214,7 @@ function hoistCodeBlocksAndSpans(text) {
     }
     // we can safely hoist the code block
     var hash = md5(content);
-    // only remove trailing whitespace
-    content = content.replace(/\s+$/, "");
-    hoisted[hash] = escape(outdent(showBackslashEscapedCharacters(content)));
+    hoisted[hash] = escape(outdent(showBackslashEscapedCharacters(removeEmptyLines(content))));
     return before + "    " + hash + "\n";
   });
 
diff --git a/test/javascripts/lib/markdown-test.js.es6 b/test/javascripts/lib/markdown-test.js.es6
index 6ae727c5504..f5859165f18 100644
--- a/test/javascripts/lib/markdown-test.js.es6
+++ b/test/javascripts/lib/markdown-test.js.es6
@@ -529,6 +529,6 @@ test("censoring", function() {
 
 test("code blocks/spans hoisting", function() {
   cooked("```\n\n    some code\n```",
-         "<p><pre><code class=\"lang-auto\">some code</code></pre></p>",
+         "<p><pre><code class=\"lang-auto\">    some code</code></pre></p>",
          "it works when nesting standard markdown code blocks within a fenced code block");
 });