Add additional text prefix in cross project labels

app/helpers/labels_helper.rb

@@ -50,7 +50,7 @@ module LabelsHelper
     @project.labels.pluck(:title)
   end
 
-  def render_colored_label(label)
+  def render_colored_label(label, label_prefix = '')
     label_color = label.color || Label::DEFAULT_COLOR
     text_color = text_color_for_bg(label_color)
 
@@ -58,11 +58,16 @@ module LabelsHelper
     # by LabelReferenceFilter
     span = %(<span class="label color-label") +
       %( style="background-color: #{label_color}; color: #{text_color}">) +
-      escape_once(label.name) + '</span>'
+      label_prefix + escape_once(label.name) + '</span>'
 
     span.html_safe
   end
 
+  def render_colored_cross_project_label(label)
+    label_prefix = "#{label.project.path_with_namespace} &raquo; "
+    render_colored_label(label, label_prefix)
+  end
+
   def suggested_colors
     [
       '#0033CC',
@@ -119,5 +124,6 @@ module LabelsHelper
   end
 
   # Required for Banzai::Filter::LabelReferenceFilter
-  module_function :render_colored_label, :text_color_for_bg, :escape_once
+  module_function :render_colored_label, :render_colored_cross_project_label,
+                  :text_color_for_bg, :escape_once
 end

app/models/label.rb

@@ -67,6 +67,7 @@ class Label < ActiveRecord::Base
     nil
   end
 
+  ##
   # Returns the String necessary to reference this Label in Markdown
   #
   # format - Symbol format to use (default: :id, optional: :name)
@@ -78,6 +79,7 @@ class Label < ActiveRecord::Base
   #   Label.first.to_reference(project)       # => "gitlab-org/gitlab-ce~1"
   #
   # Returns a String
+  #
   def to_reference(from_project = nil, format: :id)
     reference = label_format_reference(format)
 
@@ -88,7 +90,6 @@ class Label < ActiveRecord::Base
     end
   end
 
-
   def open_issues_count
     issues.opened.count
   end

lib/banzai/filter/label_reference_filter.rb

@@ -40,8 +40,12 @@ module Banzai
                                                                    only_path:  context[:only_path])
       end
 
-      def object_link_text(object, _matches)
+      def object_link_text(object, matches)
+        if context[:project] == object.project
           LabelsHelper.render_colored_label(object)
+        else
+          LabelsHelper.render_colored_cross_project_label(object)
+        end
       end
 
       # Parameters to pass to `Label.find_by` based on the given arguments