9 files changed, 72 insertions, 4 deletions
diff --git a/app/serializers/analytics_build_entity.rb b/app/serializers/analytics_build_entity.rb
index ad7ad020b03..bdc22d71202 100644
--- a/app/serializers/analytics_build_entity.rb
+++ b/app/serializers/analytics_build_entity.rb
@@ -35,6 +35,6 @@ class AnalyticsBuildEntity < Grape::Entity
   private
 
   def url_to(route, build, id = nil)
-    public_send("#{route}_url", build.project.namespace, build.project, id || build)
+    public_send("#{route}_url", build.project.namespace, build.project, id || build) # rubocop:disable GitlabSecurity/PublicSend
   end
 end
diff --git a/app/serializers/analytics_issue_entity.rb b/app/serializers/analytics_issue_entity.rb
index 44c50f18613..b7d95ea020f 100644
--- a/app/serializers/analytics_issue_entity.rb
+++ b/app/serializers/analytics_issue_entity.rb
@@ -24,6 +24,6 @@ class AnalyticsIssueEntity < Grape::Entity
   private
 
   def url_to(route, id)
-    public_send("#{route}_url", request.project.namespace, request.project, id)
+    public_send("#{route}_url", request.project.namespace, request.project, id) # rubocop:disable GitlabSecurity/PublicSend
   end
 end
diff --git a/app/serializers/blob_entity.rb b/app/serializers/blob_entity.rb
new file mode 100644
index 00000000000..56f173e5a27
--- /dev/null
+++ b/app/serializers/blob_entity.rb
@@ -0,0 +1,17 @@
+class BlobEntity < Grape::Entity
+  include RequestAwareEntity
+
+  expose :id, :path, :name, :mode
+
+  expose :last_commit do |blob|
+    request.project.repository.last_commit_for_path(blob.commit_id, blob.path)
+  end
+
+  expose :icon do |blob|
+    IconsHelper.file_type_icon_class('file', blob.mode, blob.name)
+  end
+
+  expose :url do |blob|
+    project_blob_path(request.project, File.join(request.ref, blob.path))
+  end
+end
diff --git a/app/serializers/job_entity.rb b/app/serializers/job_entity.rb
index d6de43bcbcb..72e56a2c77f 100644
--- a/app/serializers/job_entity.rb
+++ b/app/serializers/job_entity.rb
@@ -46,6 +46,6 @@ class JobEntity < Grape::Entity
   end
 
   def path_to(route, build)
-    send("#{route}_path", build.project.namespace, build.project, build)
+    send("#{route}_path", build.project.namespace, build.project, build) # rubocop:disable GitlabSecurity/PublicSend
   end
 end
diff --git a/app/serializers/merge_request_entity.rb b/app/serializers/merge_request_entity.rb
index 7f17f2bf604..07650ce6f20 100644
--- a/app/serializers/merge_request_entity.rb
+++ b/app/serializers/merge_request_entity.rb
@@ -2,7 +2,6 @@ class MergeRequestEntity < IssuableEntity
   include RequestAwareEntity
 
   expose :in_progress_merge_commit_sha
-  expose :locked_at
   expose :merge_commit_sha
   expose :merge_error
   expose :merge_params
@@ -32,6 +31,7 @@ class MergeRequestEntity < IssuableEntity
   expose :head_pipeline, with: PipelineDetailsEntity, as: :pipeline
 
   # Booleans
+  expose :merge_ongoing?, as: :merge_ongoing
   expose :work_in_progress?, as: :work_in_progress
   expose :source_branch_exists?, as: :source_branch_exists
   expose :mergeable_discussions_state?, as: :mergeable_discussions_state
diff --git a/app/serializers/submodule_entity.rb b/app/serializers/submodule_entity.rb
new file mode 100644
index 00000000000..9a7eb5e7880
--- /dev/null
+++ b/app/serializers/submodule_entity.rb
@@ -0,0 +1,23 @@
+class SubmoduleEntity < Grape::Entity
+  include RequestAwareEntity
+
+  expose :id, :path, :name, :mode
+
+  expose :icon do |blob|
+    'archive'
+  end
+
+  expose :project_url do |blob|
+    submodule_links(blob, request).first
+  end
+
+  expose :tree_url do |blob|
+    submodule_links(blob, request).last
+  end
+
+  private
+
+  def submodule_links(blob, request)
+    @submodule_links ||= SubmoduleHelper.submodule_links(blob, request.ref, request.repository)
+  end
+end
diff --git a/app/serializers/tree_entity.rb b/app/serializers/tree_entity.rb
new file mode 100644
index 00000000000..555e5cf83bd
--- /dev/null
+++ b/app/serializers/tree_entity.rb
@@ -0,0 +1,17 @@
+class TreeEntity < Grape::Entity
+  include RequestAwareEntity
+
+  expose :id, :path, :name, :mode
+
+  expose :last_commit do |tree|
+    request.project.repository.last_commit_for_path(tree.commit_id, tree.path)
+  end
+
+  expose :icon do |tree|
+    IconsHelper.file_type_icon_class('folder', tree.mode, tree.name)
+  end
+
+  expose :url do |tree|
+    project_tree_path(request.project, File.join(request.ref, tree.path))
+  end
+end
diff --git a/app/serializers/tree_root_entity.rb b/app/serializers/tree_root_entity.rb
new file mode 100644
index 00000000000..23b65aa4a4c
--- /dev/null
+++ b/app/serializers/tree_root_entity.rb
@@ -0,0 +1,8 @@
+# TODO: Inherit from TreeEntity, when `Tree` implements `id` and `name` like `Gitlab::Git::Tree`.
+class TreeRootEntity < Grape::Entity
+  expose :path
+  
+  expose :trees, using: TreeEntity
+  expose :blobs, using: BlobEntity
+  expose :submodules, using: SubmoduleEntity
+end
diff --git a/app/serializers/tree_serializer.rb b/app/serializers/tree_serializer.rb
new file mode 100644
index 00000000000..713ade23bc9
--- /dev/null
+++ b/app/serializers/tree_serializer.rb
@@ -0,0 +1,3 @@
+class TreeSerializer < BaseSerializer
+  entity TreeRootEntity
+end