Enable CacheMarkdownField for the remaining models

This commit alters views for the following models to use the markdown cache if
present:

* AbuseReport
* Appearance
* ApplicationSetting
* BroadcastMessage
* Group
* Issue
* Label
* MergeRequest
* Milestone
* Project

At the same time, calls to `escape_once` have been moved into the `single_line`
Banzai pipeline, so they can't be missed out by accident and the work is done
at save, rather than render, time.

2 files changed, 13 insertions, 0 deletions

diff --git a/lib/banzai/filter/html_entity_filter.rb b/lib/banzai/filter/html_entity_filter.rb
new file mode 100644
index 00000000000..4ef8b3b6dcf
--- /dev/null
+++ b/lib/banzai/filter/html_entity_filter.rb
@@ -0,0 +1,12 @@
+require 'erb'
+
+module Banzai
+  module Filter
+    # Text filter that escapes these HTML entities: & " < >
+    class HTMLEntityFilter < HTML::Pipeline::TextFilter
+      def call
+        ERB::Util.html_escape(text)
+      end
+    end
+  end
+end
diff --git a/lib/banzai/pipeline/single_line_pipeline.rb b/lib/banzai/pipeline/single_line_pipeline.rb
index ba2555df98d..30bc035d085 100644
--- a/lib/banzai/pipeline/single_line_pipeline.rb
+++ b/lib/banzai/pipeline/single_line_pipeline.rb
@@ -3,6 +3,7 @@ module Banzai
     class SingleLinePipeline < GfmPipeline
       def self.filters
         @filters ||= FilterArray[
+          Filter::HTMLEntityFilter,
           Filter::SanitizationFilter,
 
           Filter::EmojiFilter,