Remove default value for organization_id

The feature flag has been enabled globally
and can be removed

Changelog: changed

app/models/namespace.rb

@@ -120,7 +120,7 @@ class Namespace < ApplicationRecord
   has_many :bot_users, through: :bot_user_details, source: :user
 
   validates :owner, presence: true, if: ->(n) { n.owner_required? }
-  validates :organization, presence: true, if: :require_organization?
+  validates :organization, presence: true
   validates :name,
     presence: true,
     length: { maximum: 255 }
@@ -161,13 +161,7 @@ class Namespace < ApplicationRecord
   validate :nesting_level_allowed, unless: -> { project_namespace? }
   validate :changing_shared_runners_enabled_is_allowed, unless: -> { project_namespace? }
   validate :changing_allow_descendants_override_disabled_shared_runners_is_allowed, unless: -> { project_namespace? }
-  validate :parent_organization_match, if: :require_organization?
-
-  attribute :organization_id, :integer, default: -> do
-    return if Feature.enabled?(:require_organization, Feature.current_request)
-
-    Organizations::Organization::DEFAULT_ORGANIZATION_ID
-  end
+  validate :parent_organization_match
 
   delegate :name, to: :owner, allow_nil: true, prefix: true
   delegate :avatar_url, to: :owner, allow_nil: true
@@ -772,12 +766,6 @@ def pipeline_variables_default_role
 
   private
 
-  def require_organization?
-    return false unless Feature.enabled?(:require_organization, Feature.current_request)
-
-    Gitlab::SafeRequestStore.fetch(:require_organization) { true } # rubocop:disable Style/RedundantFetchBlock -- This fetch has a different interface
-  end
-
   def parent_organization_match
     return unless parent
     return if parent.organization_id == organization_id

config/feature_flags/gitlab_com_derisk/require_organization.yml

----
-name: require_organization
-feature_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/411832
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/155732
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/470839
-milestone: '17.3'
-group: group::tenant scale
-type: gitlab_com_derisk
-default_enabled: false

spec/models/namespace_spec.rb

@@ -284,54 +284,6 @@
     end
   end
 
-  describe 'default values' do
-    context 'organzation_id' do
-      context 'when FF require_organization is enabled' do
-        context 'and organization is set' do
-          let(:created_namespace) { build(:group) }
-
-          it 'is valid' do
-            expect(created_namespace).to be_valid
-          end
-        end
-
-        context 'and organization is not set' do
-          let(:created_namespace) { build(:group) }
-
-          before do
-            created_namespace.organization_id = nil
-          end
-
-          it 'is invalid' do
-            expect(created_namespace).to be_invalid
-          end
-        end
-      end
-
-      context 'when FF require_organization is disabled' do
-        before do
-          stub_feature_flags(require_organization: false)
-        end
-
-        context 'and database has a default value' do
-          before do
-            described_class.connection.execute("ALTER TABLE namespaces ALTER COLUMN organization_id SET DEFAULT 100")
-            described_class.reset_column_information
-          end
-
-          after do
-            described_class.connection.execute("ALTER TABLE namespaces ALTER COLUMN organization_id SET DEFAULT 1")
-            described_class.reset_column_information
-          end
-
-          it 'uses value from model' do
-            expect(described_class.new.organization_id).to eq(Organizations::Organization::DEFAULT_ORGANIZATION_ID)
-          end
-        end
-      end
-    end
-  end
-
   describe "ReferencePatternValidation" do
     subject { described_class.reference_pattern }
 
@@ -803,26 +755,6 @@
     it { is_expected.to include_module(Namespaces::Traversal::LinearScopes) }
   end
 
-  context 'when feature flag require_organization is disabled', :request_store do
-    before do
-      stub_feature_flags(require_organization: false)
-    end
-
-    it 'does not require organization' do
-      namespace.organization = nil
-
-      expect(namespace.valid?).to eq(true)
-    end
-  end
-
-  context 'when feature flag require_organization is enabled', :request_store do
-    it 'does require organization' do
-      namespace.organization = nil
-
-      expect(namespace.valid?).to eq(false)
-    end
-  end
-
   describe '#traversal_ids' do
     let(:namespace) { build(:group) }