Render MR commit SHA instead "diffs" when viableosw-41401-render-mr-commit-sha-instead-diffs

5 files changed, 44 insertions, 5 deletions

diff --git a/lib/banzai/filter/abstract_reference_filter.rb b/lib/banzai/filter/abstract_reference_filter.rb
index c9e3f8ce42b..c3a03f13306 100644
--- a/lib/banzai/filter/abstract_reference_filter.rb
+++ b/lib/banzai/filter/abstract_reference_filter.rb
@@ -171,7 +171,7 @@ module Banzai
           end
 
           if object
-            title = object_link_title(object)
+            title = object_link_title(object, matches)
             klass = reference_class(object_sym)
 
             data = data_attributes_for(link_content || match, parent, object,
@@ -216,7 +216,7 @@ module Banzai
         extras
       end
 
-      def object_link_title(object)
+      def object_link_title(object, matches)
         object.title
       end
 
diff --git a/lib/banzai/filter/commit_range_reference_filter.rb b/lib/banzai/filter/commit_range_reference_filter.rb
index 21bcb1c5ca8..99fa2d9d8fb 100644
--- a/lib/banzai/filter/commit_range_reference_filter.rb
+++ b/lib/banzai/filter/commit_range_reference_filter.rb
@@ -34,7 +34,7 @@ module Banzai
                                         range.to_param.merge(only_path: context[:only_path]))
       end
 
-      def object_link_title(range)
+      def object_link_title(range, matches)
         nil
       end
     end
diff --git a/lib/banzai/filter/label_reference_filter.rb b/lib/banzai/filter/label_reference_filter.rb
index d5360ad8f68..50db674b655 100644
--- a/lib/banzai/filter/label_reference_filter.rb
+++ b/lib/banzai/filter/label_reference_filter.rb
@@ -77,7 +77,7 @@ module Banzai
         CGI.unescapeHTML(text.to_s)
       end
 
-      def object_link_title(object)
+      def object_link_title(object, matches)
         # use title of wrapped element instead
         nil
       end
diff --git a/lib/banzai/filter/merge_request_reference_filter.rb b/lib/banzai/filter/merge_request_reference_filter.rb
index b3cfa97d0e0..5cbdb01c130 100644
--- a/lib/banzai/filter/merge_request_reference_filter.rb
+++ b/lib/banzai/filter/merge_request_reference_filter.rb
@@ -17,10 +17,19 @@ module Banzai
                                             only_path: context[:only_path])
       end
 
+      def object_link_title(object, matches)
+        object_link_commit_title(object, matches) || super
+      end
+
       def object_link_text_extras(object, matches)
         extras = super
 
+        if commit_ref = object_link_commit_ref(object, matches)
+          return extras.unshift(commit_ref)
+        end
+
         path = matches[:path] if matches.names.include?("path")
+
         case path
         when '/diffs'
           extras.unshift "diffs"
@@ -38,6 +47,36 @@ module Banzai
           .where(iid: ids.to_a)
           .includes(target_project: :namespace)
       end
+
+      private
+
+      def object_link_commit_title(object, matches)
+        object_link_commit(object, matches)&.title
+      end
+
+      def object_link_commit_ref(object, matches)
+        object_link_commit(object, matches)&.short_id
+      end
+
+      def object_link_commit(object, matches)
+        return unless matches.names.include?('query') && query = matches[:query]
+
+        # Removes leading "?". CGI.parse expects "arg1&arg2&arg3"
+        params = CGI.parse(query.sub(/^\?/, ''))
+
+        return unless commit_sha = params['commit_id']&.first
+
+        if commit = find_commit_by_sha(object, commit_sha)
+          Commit.from_hash(commit.to_hash, object.project)
+        end
+      end
+
+      def find_commit_by_sha(object, commit_sha)
+        @all_commits ||= {}
+        @all_commits[object.id] ||= object.all_commits
+
+        @all_commits[object.id].find { |commit| commit.sha == commit_sha }
+      end
     end
   end
 end
diff --git a/lib/banzai/filter/milestone_reference_filter.rb b/lib/banzai/filter/milestone_reference_filter.rb
index 8ec696ce5fc..1a1d7dbeb3d 100644
--- a/lib/banzai/filter/milestone_reference_filter.rb
+++ b/lib/banzai/filter/milestone_reference_filter.rb
@@ -84,7 +84,7 @@ module Banzai
         end
       end
 
-      def object_link_title(object)
+      def object_link_title(object, matches)
         nil
       end
     end