Use normal associations instead of polymorphic.

We can't properly use foreign keys on columns that are configured for
polymorphic associations which has disadvantages related to data
integrity and storage. Given we only use time tracking for Issues and
Merge Requests we're moving to the usage of regular associations.

1 files changed, 17 insertions, 1 deletions

diff --git a/app/models/timelog.rb b/app/models/timelog.rb
index f768c4e3da5..e166cf69703 100644
--- a/app/models/timelog.rb
+++ b/app/models/timelog.rb
@@ -1,6 +1,22 @@
 class Timelog < ActiveRecord::Base
   validates :time_spent, :user, presence: true
+  validate :issuable_id_is_present
 
-  belongs_to :trackable, polymorphic: true
+  belongs_to :issue
+  belongs_to :merge_request
   belongs_to :user
+
+  def issuable
+    issue || merge_request
+  end
+
+  private
+
+  def issuable_id_is_present
+    if issue_id && merge_request_id
+      errors.add(:base, 'Only Issue ID or Merge Request ID is required')
+    elsif issuable.nil?
+      errors.add(:base, 'Issue or Merge Request ID is required')
+    end
+  end
 end