FIX: `<pre>` blocks were adding too many new lines.

app/assets/javascripts/discourse/dialects/code_dialect.js

@@ -1,9 +1,5 @@
 /**
-  Support for github style code blocks, here you begin with three backticks and supply a language,
-  The language is made into a class on the resulting `<code>` element.
-
-  @event register
-  @namespace Discourse.Dialect
+  Support for various code blocks
 **/
 
 var acceptableCodeClasses =
@@ -46,3 +42,14 @@ Discourse.Dialect.on('parseNode', function (event) {
     node[node.length-1] = Handlebars.Utils.escapeExpression(contents.replace(regexp,''));
   }
 });
+
+Discourse.Dialect.replaceBlock({
+  start: /(<pre[^\>]*\>)([\s\S]*)/igm,
+  stop: '</pre>',
+  rawContents: true,
+  skipIfTradtionalLinebreaks: true,
+
+  emitter: function(blockContents) {
+    return ['p', ['pre', blockContents.join("\n")]];
+  }
+});

app/assets/javascripts/discourse/dialects/dialect.js

@@ -333,6 +333,12 @@ Discourse.Dialect = {
   replaceBlock: function(args) {
     this.registerBlock(args.start.toString(), function(block, next) {
 
+      var linebreaks = dialect.options.traditional_markdown_linebreaks ||
+          Discourse.SiteSettings.traditional_markdown_linebreaks;
+
+      // Some replacers should not be run with traditional linebreaks
+      if (linebreaks && args.skipIfTradtionalLinebreaks) { return; }
+
       args.start.lastIndex = 0;
       var m = (args.start).exec(block);
 

test/javascripts/lib/markdown_test.js

@@ -282,6 +282,10 @@ test("links with full urls", function() {
 
 test("Code Blocks", function() {
 
+  cooked("<pre>\nhello\n</pre>\n",
+         "<p><pre>\nhello</pre></p>",
+         "pre blocks don't include extra lines");
+
   cooked("```\na\nb\nc\n\nd\n```",
          "<p><pre><code class=\"lang-auto\">a\nb\nc\n\nd</code></pre></p>",
          "it treats new lines properly");