1 files changed, 28 insertions, 0 deletions
diff --git a/spec/support/shared_examples/models/disable_sti_shared_examples.rb b/spec/support/shared_examples/models/disable_sti_shared_examples.rb
new file mode 100644
index 00000000000..090592827d1
--- /dev/null
+++ b/spec/support/shared_examples/models/disable_sti_shared_examples.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+# Checks whether STI is disabled in +models+.
+#
+# Parameter:
+# - models: List of model classes
+RSpec.shared_examples 'Model disables STI' do
+  skip_sti_check = Gitlab::Utils.to_boolean(ENV['SKIP_STI_CHECK'], default: false)
+
+  it 'does not allow STI', :aggregate_failures, unless: skip_sti_check do
+    models.each do |model|
+      next unless model
+      next unless model < ApplicationRecord
+      next if model == model.base_class
+      next if model.allow_legacy_sti_class
+
+      expect(model).not_to have_attribute(model.inheritance_column),
+        "Do not use Single Table Inheritance (`#{model.name}` inherits `#{model.base_class.name}`). " \
+        "See https://docs.gitlab.com/ee/development/database/single_table_inheritance.html"
+    end
+  end
+end
+
+RSpec.shared_examples 'STI disabled', type: :model do # rubocop:disable RSpec/SharedGroupsMetadata -- Shared example is run within every spec tagged `type: :model`
+  include_examples 'Model disables STI' do
+    let(:models) { [described_class] }
+  end
+end