Allow for Namespace type to be either nil or User

This prepares for supporting records that have both
type == nil and type == User for namespaces.

app/models/namespace.rb

@@ -101,7 +101,7 @@ class Namespace < ApplicationRecord
       saved_change_to_name? || saved_change_to_path? || saved_change_to_parent_id?
   }
 
-  scope :for_user, -> { where(type: nil) }
+  scope :user_namespaces, -> { where(type: [nil, Namespaces::UserNamespace.sti_name]) }
   scope :sort_by_type, -> { order(Gitlab::Database.nulls_first_order(:type)) }
   scope :include_route, -> { includes(:route) }
   scope :by_parent, -> (parent) { where(parent_id: parent) }
@@ -143,9 +143,7 @@ class Namespace < ApplicationRecord
       when Namespaces::ProjectNamespace.sti_name
         Namespaces::ProjectNamespace
       when Namespaces::UserNamespace.sti_name
-        # TODO: We create a normal Namespace until
-        #       https://gitlab.com/gitlab-org/gitlab/-/merge_requests/68894 is ready
-        Namespace
+        Namespaces::UserNamespace
       else
         Namespace
       end

app/models/user.rb

@@ -112,7 +112,7 @@ class User < ApplicationRecord
   #
 
   # Namespace for personal projects
-  has_one :namespace, -> { where(type: nil) }, dependent: :destroy, foreign_key: :owner_id, inverse_of: :owner, autosave: true # rubocop:disable Cop/ActiveRecordDependent
+  has_one :namespace, -> { where(type: [nil, Namespaces::UserNamespace.sti_name]) }, dependent: :destroy, foreign_key: :owner_id, inverse_of: :owner, autosave: true # rubocop:disable Cop/ActiveRecordDependent
 
   # Profile
   has_many :keys, -> { regular_keys }, dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent
@@ -728,7 +728,7 @@ class User < ApplicationRecord
     end
 
     def find_by_full_path(path, follow_redirects: false)
-      namespace = Namespace.for_user.find_by_full_path(path, follow_redirects: follow_redirects)
+      namespace = Namespace.user_namespaces.find_by_full_path(path, follow_redirects: follow_redirects)
       namespace&.owner
     end
 

ee/app/models/ee/user.rb

@@ -454,14 +454,14 @@ module EE
 
     def namespace_union_for_owned(select = :id)
       ::Gitlab::SQL::Union.new([
-        ::Namespace.select(select).where(type: nil, owner: self),
+        ::Namespace.select(select).where(type: [nil, ::Namespaces::UserNamespace.sti_name], owner: self),
         owned_groups.select(select).where(parent_id: nil)
       ]).to_sql
     end
 
     def namespace_union_for_reporter_developer_maintainer_owned(select = :id)
       ::Gitlab::SQL::Union.new([
-        ::Namespace.select(select).where(type: nil, owner: self),
+        ::Namespace.select(select).where(type: [nil, ::Namespaces::UserNamespace.sti_name], owner: self),
         reporter_developer_maintainer_owned_groups.select(select).where(parent_id: nil)
       ]).to_sql
     end

ee/spec/features/projects/insights_spec.rb

@@ -5,7 +5,9 @@ require 'spec_helper'
 RSpec.describe 'Project Insights' do
   it_behaves_like 'Insights page' do
     let_it_be(:entity) { create(:project) }
-    let(:route) { url_for([entity.namespace, entity, :insights]) }
     let(:path) { project_insights_path(entity) }
+    let(:route) do
+      project_insights_url(entity)
+    end
   end
 end

ee/spec/models/ee/user_spec.rb

@@ -1336,12 +1336,18 @@ RSpec.describe User do
   end
 
   context 'paid namespaces' do
-    let_it_be(:user) { create(:user) }
+    using RSpec::Parameterized::TableSyntax
+
     let_it_be(:ultimate_group) { create(:group_with_plan, plan: :ultimate_plan) }
     let_it_be(:bronze_group) { create(:group_with_plan, plan: :bronze_plan) }
     let_it_be(:free_group) { create(:group_with_plan, plan: :free_plan) }
     let_it_be(:group_without_plan) { create(:group) }
 
+    where(namespace_type: [:namespace, :user_namespace])
+
+    with_them do
+      let(:user) { create(:user, namespace: create(namespace_type)) }
+
       describe '#has_paid_namespace?' do
         context 'when the user has Reporter or higher on at least one paid group' do
           it 'returns true' do
@@ -1400,6 +1406,7 @@ RSpec.describe User do
         end
       end
     end
+  end
 
   describe '#gitlab_employee?' do
     using RSpec::Parameterized::TableSyntax

spec/factories/namespaces/user_namespaces.rb

+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :user_namespace, class: 'Namespaces::UserNamespace', parent: :namespace do
+    sequence(:name) { |n| "user_namespace#{n}" }
+    type { Namespaces::UserNamespace.sti_name }
+  end
+end

spec/models/namespace_spec.rb

@@ -200,9 +200,7 @@ RSpec.describe Namespace do
       let(:namespace_type) { user_sti_name }
 
       it 'is valid' do
-        # TODO: We create a normal Namespace until
-        #       https://gitlab.com/gitlab-org/gitlab/-/merge_requests/68894 is ready
-        expect(Namespace.find(namespace.id)).to be_a(Namespace)
+        expect(Namespace.find(namespace.id)).to be_a(Namespaces::UserNamespace)
         expect(namespace.kind).to eq('user')
         expect(namespace.user_namespace?).to be_truthy
       end
@@ -221,7 +219,7 @@ RSpec.describe Namespace do
     context 'creating an unknown Namespace type' do
       let(:namespace_type) { 'One' }
 
-      it 'defaults to a Namespace' do
+      it 'creates a default Namespace' do
         expect(Namespace.find(namespace.id)).to be_a(Namespace)
         expect(namespace.kind).to eq('user')
         expect(namespace.user_namespace?).to be_truthy

spec/models/namespaces/user_namespace_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+# Main user namespace functionality it still in `Namespace`, so most
+# of the specs are in `namespace_spec.rb`.
+# UserNamespace specific specs will end up being migrated here.
+RSpec.describe Namespaces::UserNamespace, type: :model do
+  describe 'validations' do
+    it { is_expected.to validate_presence_of(:owner) }
+  end
+end

spec/models/user_spec.rb

@@ -2542,7 +2542,12 @@ RSpec.describe User do
   end
 
   describe '.find_by_full_path' do
-    let!(:user) { create(:user) }
+    using RSpec::Parameterized::TableSyntax
+
+    where(namespace_type: [:namespace, :user_namespace])
+
+    with_them do
+      let!(:user) { create(:user, namespace: create(namespace_type)) }
 
       context 'with a route matching the given path' do
         let!(:route) { user.namespace.route }
@@ -2611,6 +2616,7 @@ RSpec.describe User do
         end
       end
     end
+  end
 
   describe 'all_ssh_keys' do
     it { is_expected.to have_many(:keys).dependent(:destroy) }