Merge branch '337099-cablett-namespace-owner-validation' into 'master'

Refactor namespace owner validation logic

See merge request gitlab-org/gitlab!69201

app/models/namespace.rb

@@ -57,7 +57,7 @@ class Namespace < ApplicationRecord
   has_one :admin_note, inverse_of: :namespace
   accepts_nested_attributes_for :admin_note, update_only: true
 
-  validates :owner, presence: true, if: ->(n) { n.type.nil? }
+  validates :owner, presence: true, if: ->(n) { n.owner_required? }
   validates :name,
     presence: true,
     length: { maximum: 255 }
@@ -266,6 +266,10 @@ class Namespace < ApplicationRecord
     type.nil? || type == Namespaces::UserNamespace.sti_name || !(group? || project?)
   end
 
+  def owner_required?
+    user?
+  end
+
   def find_fork_of(project)
     return unless project.fork_network
 

app/models/namespaces/project_namespace.rb

@@ -4,6 +4,8 @@ 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

spec/models/namespace_spec.rb

@@ -344,6 +344,12 @@ RSpec.describe Namespace do
     end
   end
 
+  describe '#owner_required?' do
+    specify { expect(build(:project_namespace).owner_required?).to be_falsey }
+    specify { expect(build(:group).owner_required?).to be_falsey }
+    specify { expect(build(:namespace).owner_required?).to be_truthy }
+  end
+
   describe '#visibility_level_field' do
     it { expect(namespace.visibility_level_field).to eq(:visibility_level) }
   end

spec/models/namespaces/project_namespace_spec.rb

@@ -7,6 +7,10 @@ RSpec.describe Namespaces::ProjectNamespace, type: :model do
     it { is_expected.to have_one(:project).with_foreign_key(:project_namespace_id).inverse_of(:project_namespace) }
   end
 
+  describe 'validations' do
+    it { is_expected.not_to validate_presence_of :owner }
+  end
+
   context 'when deleting project namespace' do
     # using delete rather than destroy due to `delete` skipping AR hooks/callbacks
     # so it's ensured to work at the DB level. Uses ON DELETE CASCADE on foreign key