Fix bug where replies to commit notes displayed in the MR discussion tab wouldn't show up on the commit page

CHANGELOG

@@ -6,6 +6,9 @@ v 8.11.0 (unreleased)
   - Retrieve rendered HTML from cache in one request
   - Load project invited groups and members eagerly in ProjectTeam#fetch_members
 
+v 8.10.1 (unreleased)
+ - Fix bug where replies to commit notes displayed in the MR discussion tab wouldn't show up on the commit page
+
 v 8.10.0
   - Fix profile activity heatmap to show correct day name (eanplatter)
   - Speed up ExternalWikiHelper#get_project_wiki_path

app/models/note.rb

@@ -69,7 +69,7 @@ class Note < ActiveRecord::Base
              project: [:project_members, { group: [:group_members] }])
   end
 
-  before_validation :clear_blank_line_code!
+  before_validation :nullify_blank_type, :nullify_blank_line_code
   after_save :keep_around_commit
 
   class << self
@@ -217,10 +217,6 @@ class Note < ActiveRecord::Base
     !system?
   end
 
-  def clear_blank_line_code!
-    self.line_code = nil if self.line_code.blank?
-  end
-
   def can_be_award_emoji?
     noteable.is_a?(Awardable)
   end
@@ -238,4 +234,12 @@ class Note < ActiveRecord::Base
   def keep_around_commit
     project.repository.keep_around(self.commit_id)
   end
+
+  def nullify_blank_type
+    self.type = nil if self.type.blank?
+  end
+
+  def nullify_blank_line_code
+    self.line_code = nil if self.line_code.blank?
+  end
 end

db/migrate/20160722221922_nullify_blank_type_on_notes.rb

@@ -0,0 +1,9 @@
+class NullifyBlankTypeOnNotes < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    execute "UPDATE notes SET type = NULL WHERE type = ''"
+  end
+end