Render milestone links as references

4 files changed, 47 insertions, 18 deletions

diff --git a/lib/banzai/filter/abstract_reference_filter.rb b/lib/banzai/filter/abstract_reference_filter.rb
index 6b200dc2017..36d8c12e2b3 100644
--- a/lib/banzai/filter/abstract_reference_filter.rb
+++ b/lib/banzai/filter/abstract_reference_filter.rb
@@ -60,27 +60,31 @@ module Banzai
       end
 
       def call
-        # `#123`
-        replace_text_nodes_matching(object_class.reference_pattern) do |content|
-          object_link_filter(content, object_class.reference_pattern)
-        end
+        if object_class.reference_pattern
+          # `#123`
+          replace_text_nodes_matching(object_class.reference_pattern) do |content|
+            object_link_filter(content, object_class.reference_pattern)
+          end
 
-        # `[Issue](#123)`, which is turned into
-        # `<a href="#123">Issue</a>`
-        replace_link_nodes_with_href(object_class.reference_pattern) do |link, text|
-          object_link_filter(link, object_class.reference_pattern, link_text: text)
+          # `[Issue](#123)`, which is turned into
+          # `<a href="#123">Issue</a>`
+          replace_link_nodes_with_href(object_class.reference_pattern) do |link, text|
+            object_link_filter(link, object_class.reference_pattern, link_text: text)
+          end
         end
 
-        # `http://gitlab.example.com/namespace/project/issues/123`, which is turned into
-        # `<a href="http://gitlab.example.com/namespace/project/issues/123">http://gitlab.example.com/namespace/project/issues/123</a>`
-        replace_link_nodes_with_text(object_class.link_reference_pattern) do |text|
-          object_link_filter(text, object_class.link_reference_pattern)
-        end
+        if object_class.link_reference_pattern
+          # `http://gitlab.example.com/namespace/project/issues/123`, which is turned into
+          # `<a href="http://gitlab.example.com/namespace/project/issues/123">http://gitlab.example.com/namespace/project/issues/123</a>`
+          replace_link_nodes_with_text(object_class.link_reference_pattern) do |text|
+            object_link_filter(text, object_class.link_reference_pattern)
+          end
 
-        # `[Issue](http://gitlab.example.com/namespace/project/issues/123)`, which is turned into
-        # `<a href="http://gitlab.example.com/namespace/project/issues/123">Issue</a>`
-        replace_link_nodes_with_href(object_class.link_reference_pattern) do |link, text|
-          object_link_filter(link, object_class.link_reference_pattern, link_text: text)
+          # `[Issue](http://gitlab.example.com/namespace/project/issues/123)`, which is turned into
+          # `<a href="http://gitlab.example.com/namespace/project/issues/123">Issue</a>`
+          replace_link_nodes_with_href(object_class.link_reference_pattern) do |link, text|
+            object_link_filter(link, object_class.link_reference_pattern, link_text: text)
+          end
         end
       end
 
diff --git a/lib/banzai/filter/milestone_reference_filter.rb b/lib/banzai/filter/milestone_reference_filter.rb
new file mode 100644
index 00000000000..f99202af5e8
--- /dev/null
+++ b/lib/banzai/filter/milestone_reference_filter.rb
@@ -0,0 +1,24 @@
+require 'banzai'
+
+module Banzai
+  module Filter
+    # HTML filter that replaces milestone references with links.
+    #
+    # This filter supports cross-project references.
+    class MilestoneReferenceFilter < AbstractReferenceFilter
+      def self.object_class
+        Milestone
+      end
+
+      def find_object(project, id)
+        project.milestones.find_by(iid: id)
+      end
+
+      def url_for_object(issue, project)
+        h = Gitlab::Application.routes.url_helpers
+        h.namespace_project_milestone_url(project.namespace, project, milestone,
+                                        only_path: context[:only_path])
+      end
+    end
+  end
+end
diff --git a/lib/banzai/pipeline/gfm_pipeline.rb b/lib/banzai/pipeline/gfm_pipeline.rb
index 38750b55ec7..838155e8831 100644
--- a/lib/banzai/pipeline/gfm_pipeline.rb
+++ b/lib/banzai/pipeline/gfm_pipeline.rb
@@ -22,6 +22,7 @@ module Banzai
           Filter::CommitRangeReferenceFilter,
           Filter::CommitReferenceFilter,
           Filter::LabelReferenceFilter,
+          Filter::MilestoneReferenceFilter,
 
           Filter::TaskListFilter
         ]
diff --git a/lib/gitlab/reference_extractor.rb b/lib/gitlab/reference_extractor.rb
index 0a70d21b1ce..c87068051ab 100644
--- a/lib/gitlab/reference_extractor.rb
+++ b/lib/gitlab/reference_extractor.rb
@@ -18,7 +18,7 @@ module Gitlab
       super(text, context.merge(project: project))
     end
 
-    %i(user label merge_request snippet commit commit_range).each do |type|
+    %i(user label milestone merge_request snippet commit commit_range).each do |type|
       define_method("#{type}s") do
         @references[type] ||= references(type, project: project, current_user: current_user)
       end