Fix create service spec

Remove circular inverse_of between project and project_namespace
to fix create service spec.

app/models/namespaces/project_namespace.rb

@@ -4,8 +4,6 @@ module Namespaces
   class ProjectNamespace < Namespace
     has_one :project, foreign_key: :project_namespace_id, inverse_of: :project_namespace
 
-    validates :project, presence: true
-
     def self.sti_name
       'Project'
     end

app/models/project.rb

@@ -147,7 +147,7 @@ class Project < ApplicationRecord
   belongs_to :namespace
   # Sync deletion via DB Trigger to ensure we do not have
   # a project without a project_namespace (or vice-versa)
-  belongs_to :project_namespace, autosave: true, class_name: 'Namespaces::ProjectNamespace', foreign_key: 'project_namespace_id', inverse_of: :project
+  belongs_to :project_namespace, autosave: true, class_name: 'Namespaces::ProjectNamespace', foreign_key: 'project_namespace_id'
   alias_method :parent, :namespace
   alias_attribute :parent_id, :namespace_id
 
@@ -476,7 +476,7 @@ class Project < ApplicationRecord
   validates :project_feature, presence: true
 
   validates :namespace, presence: true
-  validates :project_namespace, presence: true, on: :create, if: -> { self.namespace.blank? || self.root_namespace.project_namespace_creation_enabled? }
+  validates :project_namespace, presence: true, if: -> { self.namespace && self.root_namespace.project_namespace_creation_enabled? }
   validates :name, uniqueness: { scope: :namespace_id }
   validates :import_url, public_url: { schemes: ->(project) { project.persisted? ? VALID_MIRROR_PROTOCOLS : VALID_IMPORT_PROTOCOLS },
                                        ports: ->(project) { project.persisted? ? VALID_MIRROR_PORTS : VALID_IMPORT_PORTS },
@@ -2919,23 +2919,19 @@ class Project < ApplicationRecord
     @online_runners_with_tags ||= active_runners.with_tags.online
   end
 
-  def create_project_namespace
-    project_namespace = Namespaces::ProjectNamespace.new(project: self)
+  def ensure_project_namespace_in_sync
+    if self.namespace && self.root_namespace.project_namespace_creation_enabled?
+      if new_record? && !project_namespace
+        build_project_namespace
         sync_attributes(project_namespace)
-
-    self.project_namespace = project_namespace
       end
 
-  def ensure_project_namespace_in_sync
-    if new_record? && !project_namespace
-      create_project_namespace if !self.namespace || self.root_namespace.project_namespace_creation_enabled?
-    else
       sync_attributes(project_namespace) if sync_project_namespace?
     end
   end
 
   def sync_project_namespace?
-    changes.keys & [:name, :path, :namespace_id, :namespace, :visibility_level] && project_namespace.present?
+    (changes.keys & %w(name path namespace_id namespace visibility_level)).any? && project_namespace.present?
   end
 
   def sync_attributes(project_namespace)

spec/models/project_spec.rb

@@ -16,7 +16,7 @@ RSpec.describe Project, factory_default: :keep do
   describe 'associations' do
     it { is_expected.to belong_to(:group) }
     it { is_expected.to belong_to(:namespace) }
-    it { is_expected.to belong_to(:project_namespace).class_name('Namespaces::ProjectNamespace').with_foreign_key('project_namespace_id').inverse_of(:project) }
+    it { is_expected.to belong_to(:project_namespace).class_name('Namespaces::ProjectNamespace').with_foreign_key('project_namespace_id') }
     it { is_expected.to belong_to(:creator).class_name('User') }
     it { is_expected.to belong_to(:pool_repository) }
     it { is_expected.to have_many(:users) }
@@ -316,8 +316,8 @@ RSpec.describe Project, factory_default: :keep do
     end
 
     it 'validates the visibility' do
-      expect_any_instance_of(described_class).to receive(:visibility_level_allowed_as_fork).twice.and_call_original
-      expect_any_instance_of(described_class).to receive(:visibility_level_allowed_by_group).twice.and_call_original
+      expect_any_instance_of(described_class).to receive(:visibility_level_allowed_as_fork).and_call_original
+      expect_any_instance_of(described_class).to receive(:visibility_level_allowed_by_group).and_call_original
 
       create(:project)
     end