1 files changed, 22 insertions, 0 deletions
diff --git a/app/models/description_version.rb b/app/models/description_version.rb
new file mode 100644
index 00000000000..abab7f94212
--- /dev/null
+++ b/app/models/description_version.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+class DescriptionVersion < ApplicationRecord
+  belongs_to :issue
+  belongs_to :merge_request
+
+  validate :exactly_one_issuable
+
+  def self.issuable_attrs
+    %i(issue merge_request).freeze
+  end
+
+  private
+
+  def exactly_one_issuable
+    issuable_count = self.class.issuable_attrs.count { |attr| self["#{attr}_id"] }
+
+    errors.add(:base, "Exactly one of #{self.class.issuable_attrs.join(', ')} is required") if issuable_count != 1
+  end
+end
+
+DescriptionVersion.prepend_if_ee('EE::DescriptionVersion')