Support references to group milestones

Group milestones can only be referred to by name, not IID. They also do not
support cross-project references.

2 files changed, 64 insertions, 11 deletions

diff --git a/lib/banzai/filter/abstract_reference_filter.rb b/lib/banzai/filter/abstract_reference_filter.rb
index 685b43605ae..5db4fe77885 100644
--- a/lib/banzai/filter/abstract_reference_filter.rb
+++ b/lib/banzai/filter/abstract_reference_filter.rb
@@ -59,6 +59,12 @@ module Banzai
         # Example: project.merge_requests.find
       end
 
+      # Override if the link reference pattern produces a different ID (global
+      # ID vs internal ID, for instance) to the regular reference pattern.
+      def find_object_from_link(project, id)
+        find_object(project, id)
+      end
+
       def find_object_cached(project, id)
         if RequestStore.active?
           cache = find_objects_cache[object_class][project.id]
@@ -69,6 +75,16 @@ module Banzai
         end
       end
 
+      def find_object_from_link_cached(project, id)
+        if RequestStore.active?
+          cache = find_objects_from_link_cache[object_class][project.id]
+
+          get_or_set_cache(cache, id) { find_object_from_link(project, id) }
+        else
+          find_object_from_link(project, id)
+        end
+      end
+
       def project_from_ref_cached(ref)
         if RequestStore.active?
           cache = project_refs_cache
@@ -120,7 +136,7 @@ module Banzai
 
               if link == inner_html && inner_html =~ /\A#{link_pattern}/
                 replace_link_node_with_text(node, link) do
-                  object_link_filter(inner_html, link_pattern)
+                  object_link_filter(inner_html, link_pattern, link_reference: true)
                 end
 
                 next
@@ -128,7 +144,7 @@ module Banzai
 
               if link =~ /\A#{link_pattern}\z/
                 replace_link_node_with_href(node, link) do
-                  object_link_filter(link, link_pattern, link_content: inner_html)
+                  object_link_filter(link, link_pattern, link_content: inner_html, link_reference: true)
                 end
 
                 next
@@ -146,15 +162,26 @@ module Banzai
       # text - String text to replace references in.
       # pattern - Reference pattern to match against.
       # link_content - Original content of the link being replaced.
+      # link_reference - True if this was using the link reference pattern,
+      #                  false otherwise.
       #
       # Returns a String with references replaced with links. All links
       # have `gfm` and `gfm-OBJECT_NAME` class names attached for styling.
-      def object_link_filter(text, pattern, link_content: nil)
+      def object_link_filter(text, pattern, link_content: nil, link_reference: false)
         references_in(text, pattern) do |match, id, project_ref, namespace_ref, matches|
           project_path = full_project_path(namespace_ref, project_ref)
           project = project_from_ref_cached(project_path)
 
-          if project && object = find_object_cached(project, id)
+          if project
+            object =
+              if link_reference
+                find_object_from_link_cached(project, id)
+              else
+                find_object_cached(project, id)
+              end
+          end
+
+          if object
             title = object_link_title(object)
             klass = reference_class(object_sym)
 
@@ -303,6 +330,12 @@ module Banzai
         end
       end
 
+      def find_objects_from_link_cache
+        RequestStore[:banzai_find_objects_from_link_cache] ||= Hash.new do |hash, key|
+          hash[key] = Hash.new { |h, k| h[k] = {} }
+        end
+      end
+
       def url_for_object_cache
         RequestStore[:banzai_url_for_object] ||= Hash.new do |hash, key|
           hash[key] = Hash.new { |h, k| h[k] = {} }
diff --git a/lib/banzai/filter/milestone_reference_filter.rb b/lib/banzai/filter/milestone_reference_filter.rb
index 45c033d32a8..4fc5f211e84 100644
--- a/lib/banzai/filter/milestone_reference_filter.rb
+++ b/lib/banzai/filter/milestone_reference_filter.rb
@@ -8,8 +8,15 @@ module Banzai
         Milestone
       end
 
+      # Links to project milestones contain the IID, but when we're handling
+      # 'regular' references, we need to use the global ID to disambiguate
+      # between group and project milestones.
       def find_object(project, id)
-        project.milestones.find_by(iid: id)
+        find_milestone_with_finder(project, id: id)
+      end
+
+      def find_object_from_link(project, iid)
+        find_milestone_with_finder(project, iid: iid)
       end
 
       def references_in(text, pattern = Milestone.reference_pattern)
@@ -22,7 +29,7 @@ module Banzai
           milestone = find_milestone($~[:project], $~[:namespace], $~[:milestone_iid], $~[:milestone_name])
 
           if milestone
-            yield match, milestone.iid, $~[:project], $~[:namespace], $~
+            yield match, milestone.id, $~[:project], $~[:namespace], $~
           else
             match
           end
@@ -36,7 +43,8 @@ module Banzai
         return unless project
 
         milestone_params = milestone_params(milestone_id, milestone_name)
-        project.milestones.find_by(milestone_params)
+
+        find_milestone_with_finder(project, milestone_params)
       end
 
       def milestone_params(iid, name)
@@ -47,15 +55,27 @@ module Banzai
         end
       end
 
+      def find_milestone_with_finder(project, params)
+        finder_params = { project_ids: [project.id], order: nil }
+
+        # We don't support IID lookups for group milestones, because IIDs can
+        # clash between group and project milestones.
+        if project.group && !params[:iid]
+          finder_params[:group_ids] = [project.group.id]
+        end
+
+        MilestonesFinder.new(finder_params).execute.find_by(params)
+      end
+
       def url_for_object(milestone, project)
-        h = Gitlab::Routing.url_helpers
-        h.project_milestone_url(project, milestone,
-                                        only_path: context[:only_path])
+        Gitlab::Routing
+          .url_helpers
+          .milestone_url(milestone, only_path: context[:only_path])
       end
 
       def object_link_text(object, matches)
         milestone_link = escape_once(super)
-        reference = object.project.to_reference(project)
+        reference = object.project&.to_reference(project)
 
         if reference.present?
           "#{milestone_link} <i>in #{reference}</i>".html_safe