Handle external issues in IssueReferenceFilter

IssueReferenceFilter will end up processing internal issue references
when a project uses an external issues tracker while still using
internal issue references (in the form of `#\d+`). This commit ensures
that these links are rendered as external issue links, regardless of
whether the project one currently views uses an internal or external
issues tracker.

Fixes gitlab-org/gitlab-ce#19036, gitlab-com/performance#16

1 files changed, 9 insertions, 5 deletions

diff --git a/lib/banzai/filter/abstract_reference_filter.rb b/lib/banzai/filter/abstract_reference_filter.rb
index 81d66271136..d77a5e3ff09 100644
--- a/lib/banzai/filter/abstract_reference_filter.rb
+++ b/lib/banzai/filter/abstract_reference_filter.rb
@@ -160,11 +160,7 @@ module Banzai
             title = object_link_title(object)
             klass = reference_class(object_sym)
 
-            data  = data_attribute(
-              original:     link_text || match,
-              project:      project.id,
-              object_sym => object.id
-            )
+            data = data_attributes_for(link_text || match, project, object)
 
             if matches.names.include?("url") && matches[:url]
               url = matches[:url]
@@ -183,6 +179,14 @@ module Banzai
         end
       end
 
+      def data_attributes_for(text, project, object)
+        data_attribute(
+          original:     text,
+          project:      project.id,
+          object_sym => object.id
+        )
+      end
+
       def object_link_text_extras(object, matches)
         extras = []