Remove Legacy Feature Flag Scopes

As legacy feature flags no longer exist, we can remove the bindings for
their children properties, and no longer accept attributes for them.

Note that this does not drop any data, as the development guidelines
suggest that the dropping of data should happen in a later release.

app/models/operations/feature_flag.rb

@@ -19,13 +19,10 @@ module Operations
     default_value_for :active, true
     default_value_for :version, :new_version_flag
 
-    # scopes exists only for the first version
-    has_many :scopes, class_name: 'Operations::FeatureFlagScope'
     # strategies exists only for the second version
     has_many :strategies, class_name: 'Operations::FeatureFlags::Strategy'
     has_many :feature_flag_issues
     has_many :issues, through: :feature_flag_issues
-    has_one :default_scope, -> { where(environment_scope: '*') }, class_name: 'Operations::FeatureFlagScope'
 
     validates :project, presence: true
     validates :name,
@@ -37,10 +34,7 @@ module Operations
       }
     validates :name, uniqueness: { scope: :project_id }
     validates :description, allow_blank: true, length: 0..255
-    validate :first_default_scope, on: :create, if: :has_scopes?
-    validate :version_associations
 
-    accepts_nested_attributes_for :scopes, allow_destroy: true
     accepts_nested_attributes_for :strategies, allow_destroy: true
 
     scope :ordered, -> { order(:name) }
@@ -56,7 +50,7 @@ module Operations
 
     class << self
       def preload_relations
-        preload(:scopes, strategies: :scopes)
+        preload(strategies: :scopes)
       end
 
       def for_unleash_client(project, environment)
@@ -119,27 +113,5 @@ module Operations
         active: active
       }
     end
-
-    private
-
-    def version_associations
-      if new_version_flag? && scopes.any?
-        errors.add(:version_associations, 'version 2 feature flags may not have scopes')
-      end
-    end
-
-    def first_default_scope
-      unless scopes.first.environment_scope == '*'
-        errors.add(:default_scope, 'has to be the first element')
-      end
-    end
-
-    def build_default_scope
-      scopes.build(environment_scope: '*', active: self.active)
-    end
-
-    def has_scopes?
-      scopes.any?
-    end
   end
 end

app/models/operations/feature_flag_scope.rb

-# frozen_string_literal: true
-
-# All of the legacy flags have been removed in 14.1, including all of the
-# `operations_feature_flag_scopes` rows.  Therefore, this model and the database
-# table are unused and should be removed.
-
-module Operations
-  class FeatureFlagScope < ApplicationRecord
-    prepend HasEnvironmentScope
-    include Gitlab::Utils::StrongMemoize
-
-    self.table_name = 'operations_feature_flag_scopes'
-
-    belongs_to :feature_flag
-
-    validates :environment_scope, uniqueness: {
-      scope: :feature_flag,
-      message: "(%{value}) has already been taken"
-    }
-
-    validates :environment_scope,
-      if: :default_scope?, on: :update,
-      inclusion: { in: %w(*), message: 'cannot be changed from default scope' }
-
-    validates :strategies, feature_flag_strategies: true
-
-    before_destroy :prevent_destroy_default_scope, if: :default_scope?
-
-    scope :ordered, -> { order(:id) }
-    scope :enabled, -> { where(active: true) }
-    scope :disabled, -> { where(active: false) }
-
-    def self.with_name_and_description
-      joins(:feature_flag)
-        .select(FeatureFlag.arel_table[:name], FeatureFlag.arel_table[:description])
-    end
-
-    def self.for_unleash_client(project, environment)
-      select_columns = [
-        'DISTINCT ON (operations_feature_flag_scopes.feature_flag_id) operations_feature_flag_scopes.id',
-        '(operations_feature_flags.active AND operations_feature_flag_scopes.active) AS active',
-        'operations_feature_flag_scopes.strategies',
-        'operations_feature_flag_scopes.environment_scope',
-        'operations_feature_flag_scopes.created_at',
-        'operations_feature_flag_scopes.updated_at'
-      ]
-
-      select(select_columns)
-        .with_name_and_description
-        .where(feature_flag_id: project.operations_feature_flags.select(:id))
-        .order(:feature_flag_id)
-        .on_environment(environment)
-        .reverse_order
-    end
-
-    private
-
-    def default_scope?
-      environment_scope_was == '*'
-    end
-
-    def prevent_destroy_default_scope
-      raise ActiveRecord::ReadOnlyRecord, "default scope cannot be destroyed"
-    end
-  end
-end

app/serializers/feature_flag_entity.rb

@@ -24,8 +24,8 @@ class FeatureFlagEntity < Grape::Entity
     project_feature_flag_path(feature_flag.project, feature_flag)
   end
 
-  expose :scopes, with: FeatureFlagScopeEntity do |feature_flag|
-    feature_flag.scopes.sort_by(&:id)
+  expose :scopes do |_ff|
+    []
   end
 
   expose :strategies, with: FeatureFlags::StrategyEntity do |feature_flag|

app/serializers/feature_flag_scope_entity.rb

-# frozen_string_literal: true
-
-class FeatureFlagScopeEntity < Grape::Entity
-  include RequestAwareEntity
-
-  expose :id
-  expose :active
-  expose :environment_scope
-  expose :created_at
-  expose :updated_at
-  expose :strategies
-end

lib/api/entities/feature_flag.rb

@@ -9,7 +9,9 @@ module API
       expose :version
       expose :created_at
       expose :updated_at
-      expose :scopes, using: FeatureFlag::LegacyScope
+      expose :scopes do |_ff|
+        []
+      end
       expose :strategies, using: FeatureFlag::Strategy
     end
   end

lib/api/entities/feature_flag/detailed_legacy_scope.rb

-# frozen_string_literal: true
-
-module API
-  module Entities
-    class FeatureFlag < Grape::Entity
-      class DetailedLegacyScope < LegacyScope
-        expose :name
-      end
-    end
-  end
-end

lib/api/entities/feature_flag/legacy_scope.rb

-# frozen_string_literal: true
-
-module API
-  module Entities
-    class FeatureFlag < Grape::Entity
-      class LegacyScope < Grape::Entity
-        expose :id
-        expose :active
-        expose :environment_scope
-        expose :strategies
-        expose :created_at
-        expose :updated_at
-      end
-    end
-  end
-end

spec/models/operations/feature_flag_spec.rb

@@ -13,7 +13,7 @@ RSpec.describe Operations::FeatureFlag do
 
   describe 'associations' do
     it { is_expected.to belong_to(:project) }
-    it { is_expected.to have_many(:scopes) }
+    it { is_expected.to have_many(:strategies) }
   end
 
   describe '.reference_pattern' do
@@ -52,17 +52,6 @@ RSpec.describe Operations::FeatureFlag do
     it { is_expected.to define_enum_for(:version).with_values(new_version_flag: 2) }
 
     context 'a version 2 feature flag' do
-      it 'is invalid if associated with Operations::FeatureFlagScope models' do
-        project = create(:project)
-        feature_flag = described_class.new({ name: 'test', project: project, version: 2,
-                                 scopes_attributes: [{ environment_scope: '*', active: false }] })
-
-        expect(feature_flag.valid?).to eq(false)
-        expect(feature_flag.errors.messages).to eq({
-          version_associations: ["version 2 feature flags may not have scopes"]
-        })
-      end
-
       it 'is valid if associated with Operations::FeatureFlags::Strategy models' do
         project = create(:project)
         feature_flag = described_class.create!({ name: 'test', project: project, version: 2,
@@ -81,18 +70,6 @@ RSpec.describe Operations::FeatureFlag do
     end
   end
 
-  describe 'the default scope' do
-    let_it_be(:project) { create(:project) }
-
-    context 'with a version 2 feature flag' do
-      it 'does not create a default scope' do
-        feature_flag = described_class.create!({ name: 'test', project: project, scopes_attributes: [], version: 2 })
-
-        expect(feature_flag.scopes).to eq([])
-      end
-    end
-  end
-
   describe '.enabled' do
     subject { described_class.enabled }