Add indication for closed or merged issuables in GFMadam-finish-5993-closed-issuable

Example: for issues that are closed, the links will now show '[closed]'
following the issue number. This is done as post-process after the markdown has
been loaded from the cache as the status of the issue may change between
the cache being populated and the content being displayed.

In order to avoid N+1 queries problem when rendering notes ObjectRenderer
populates the cache of referenced issuables for all notes at once,
before the post processing phase.

As a part of this change, the Banzai BaseParser#grouped_objects_for_nodes
method has been refactored to return a Hash utilising the node itself as the
key, since this was a common pattern of usage for this method.

1 files changed, 26 insertions, 20 deletions

diff --git a/lib/banzai/object_renderer.rb b/lib/banzai/object_renderer.rb
index 9f8eb0931b8..002a3341ccd 100644
--- a/lib/banzai/object_renderer.rb
+++ b/lib/banzai/object_renderer.rb
@@ -31,7 +31,8 @@ module Banzai
     #
     # Returns the same input objects.
     def render(objects, attribute)
-      documents = render_objects(objects, attribute)
+      documents = render_documents(objects, attribute)
+      documents = post_process_documents(documents, objects, attribute)
       redacted = redact_documents(documents)
 
       objects.each_with_index do |object, index|
@@ -41,9 +42,24 @@ module Banzai
       end
     end
 
-    # Renders the attribute of every given object.
-    def render_objects(objects, attribute)
-      render_attributes(objects, attribute)
+    private
+
+    def render_documents(objects, attribute)
+      pipeline = HTML::Pipeline.new([])
+
+      objects.map do |object|
+        pipeline.to_document(Banzai.render_field(object, attribute))
+      end
+    end
+
+    def post_process_documents(documents, objects, attribute)
+      # Called here to populate cache, refer to IssuableExtractor docs
+      IssuableExtractor.new(project, user).extract(documents)
+
+      documents.zip(objects).map do |document, object|
+        context = context_for(object, attribute)
+        Banzai::Pipeline[:post_process].to_document(document, context)
+      end
     end
 
     # Redacts the list of documents.
@@ -57,25 +73,15 @@ module Banzai
 
     # Returns a Banzai context for the given object and attribute.
     def context_for(object, attribute)
-      context = base_context.dup
-      context = context.merge(object.banzai_render_context(attribute))
-      context
-    end
-
-    # Renders the attributes of a set of objects.
-    #
-    # Returns an Array of `Nokogiri::HTML::Document`.
-    def render_attributes(objects, attribute)
-      objects.map do |object|
-        string = Banzai.render_field(object, attribute)
-        context = context_for(object, attribute)
-
-        Banzai::Pipeline[:relative_link].to_document(string, context)
-      end
+      base_context.merge(object.banzai_render_context(attribute))
     end
 
     def base_context
-      @base_context ||= @redaction_context.merge(current_user: user, project: project)
+      @base_context ||= @redaction_context.merge(
+        current_user: user,
+        project: project,
+        skip_redaction: true
+      )
     end
   end
 end