Fix code preview theme setting for comments, issues, merge requests, and snippets.

Also preserve code preview color scheme in events dashboard.

Assign default colors to all code blocks shown as <pre class="code highlight [color_scheme]">

Closes #1139

CHANGELOG

@@ -7,6 +7,7 @@ v 7.9.0 (unreleased)
   - Add issue and merge request events to HipChat and Slack services (Stan Hu)
   - Fix merge request URL passed to Webhooks. (Stan Hu)
   - Fix bug that caused a server error when editing a comment to "+1" or "-1" (Stan Hu)
+  - Fix code preview theme setting for comments, issues, merge requests, and snippets (Stan Hu)
   - Move labels/milestones tabs to sidebar
   - Upgrade Rails gem to version 4.1.9.
   - Improve error messages for file edit failures

app/assets/stylesheets/highlight/dark.scss

 /* https://github.com/MozMorris/tomorrow-pygments */
+pre.code.highlight.dark,
 .code.dark {
 
+  background-color: #1d1f21;
+  color: #c5c8c6;
+
   pre.code,
   .line-numbers,
   .line-numbers a {

app/assets/stylesheets/highlight/monokai.scss

 /* https://github.com/richleland/pygments-css/blob/master/monokai.css */
+pre.code.monokai,
 .code.monokai {
 
+  background: #272822;
+  color: #f8f8f2;
+
   pre.highlight,
   .line-numbers,
   .line-numbers a {

app/assets/stylesheets/highlight/solarized_dark.scss

 /* https://gist.github.com/qguv/7936275 */
+pre.code.highlight.solarized-dark,
 .code.solarized-dark {
 
+  background-color: #002b36;
+  color: #93a1a1;
+
   pre.code,
   .line-numbers,
   .line-numbers a {

app/assets/stylesheets/highlight/solarized_light.scss

 /* https://gist.github.com/qguv/7936275 */
+pre.code.highlight.solarized-light,
 .code.solarized-light {
 
+  background-color: #fdf6e3;
+  color: #586e75;
+
   pre.code,
   .line-numbers,
   .line-numbers a {

app/assets/stylesheets/highlight/white.scss

 /* https://github.com/aahan/pygments-github-style */
+pre.code.highlight.white,
 .code.white {
 
+  background-color: #fff;
+  color: #333;
+
   pre.highlight,
   .line-numbers,
   .line-numbers a {

app/helpers/events_helper.rb

@@ -166,7 +166,7 @@ module EventsHelper
 
   def event_note(text)
     text = first_line_in_markdown(text, 150)
-    sanitize(text, tags: %w(a img b pre code p))
+    sanitize(text, tags: %w(a img b pre code p span))
   end
 
   def event_commit_title(message)

app/helpers/gitlab_markdown_helper.rb

@@ -31,7 +31,9 @@ module GitlabMarkdownHelper
   def markdown(text, options={})
     unless (@markdown and options == @options)
       @options = options
-      gitlab_renderer = Redcarpet::Render::GitlabHTML.new(self, {
+      gitlab_renderer = Redcarpet::Render::GitlabHTML.new(self,
+                                                          user_color_scheme_class,
+                                                          {
                             # see https://github.com/vmg/redcarpet#darling-i-packed-you-a-couple-renderers-for-lunch-
                             filter_html: true,
                             with_toc_data: true,

lib/redcarpet/render/gitlab_html.rb

@@ -3,8 +3,9 @@ class Redcarpet::Render::GitlabHTML < Redcarpet::Render::HTML
   attr_reader :template
   alias_method :h, :template
 
-  def initialize(template, options = {})
+  def initialize(template, color_scheme, options = {})
     @template = template
+    @color_scheme = color_scheme
     @project = @template.instance_variable_get("@project")
     @options = options.dup
     super options
@@ -34,7 +35,7 @@ class Redcarpet::Render::GitlabHTML < Redcarpet::Render::HTML
     end
 
     formatter = Rugments::Formatters::HTML.new(
-      cssclass: "code highlight white #{lexer.tag}"
+      cssclass: "code highlight #{@color_scheme} #{lexer.tag}"
     )
     formatter.format(lexer.lex(code))
   end

spec/helpers/events_helper_spec.rb

@@ -4,6 +4,8 @@ describe EventsHelper do
   include ApplicationHelper
   include GitlabMarkdownHelper
 
+  let(:current_user) { create(:user, email: "current@email.com") }
+
   it 'should display one line of plain text without alteration' do
     input = 'A short, plain note'
     expect(event_note(input)).to match(input)
@@ -50,4 +52,14 @@ describe EventsHelper do
     expect(event_note(input)).to match(link_url)
     expect(event_note(input)).to match(expected_link_text)
   end
+
+  it 'should preserve code color scheme' do
+    input = "```ruby\ndef test\n  'hello world'\nend\n```"
+    expected = '<pre class="code highlight white ruby">' \
+      "<code><span class=\"k\">def</span> <span class=\"nf\">test</span>\n" \
+      "  <span class=\"s1\">\'hello world\'</span>\n" \
+      "<span class=\"k\">end</span>\n" \
+      '</code></pre>'
+    expect(event_note(input)).to eq(expected)
+  end
 end