Address reviewer comments

particuarly adding TODO comments where
code is temporary.

app/models/namespace.rb

@@ -101,6 +101,8 @@ class Namespace < ApplicationRecord
       saved_change_to_name? || saved_change_to_path? || saved_change_to_parent_id?
   }
 
+  # TODO: change to `type: Namespaces::UserNamespace.sti_name` when
+  #       working on issue https://gitlab.com/gitlab-org/gitlab/-/issues/341070
   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) }

app/models/namespaces/user_namespace.rb

 # frozen_string_literal: true
 
 # TODO: currently not created/mapped in the database, will be done in another issue
-#       https://gitlab.com/gitlab-org/gitlab/-/issues/337102
+#       https://gitlab.com/gitlab-org/gitlab/-/issues/341070
 module Namespaces
   class UserNamespace < Namespace
     def self.sti_name

app/models/user.rb

@@ -112,6 +112,8 @@ class User < ApplicationRecord
   #
 
   # Namespace for personal projects
+  # TODO: change to `type: Namespaces::UserNamespace.sti_name` when
+  #       working on issue https://gitlab.com/gitlab-org/gitlab/-/issues/341070
   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

ee/app/models/ee/user.rb

@@ -452,6 +452,8 @@ module EE
       end
     end
 
+    # TODO: change to `type: ::Namespaces::UserNamespace.sti_name` when
+    #       working on issue https://gitlab.com/gitlab-org/gitlab/-/issues/341070
     def namespace_union_for_owned(select = :id)
       ::Gitlab::SQL::Union.new([
         ::Namespace.select(select).where(type: [nil, ::Namespaces::UserNamespace.sti_name], owner: self),
@@ -459,6 +461,8 @@ module EE
       ]).to_sql
     end
 
+    # TODO: change to `type: ::Namespaces::UserNamespace.sti_name` when
+    #       working on issue https://gitlab.com/gitlab-org/gitlab/-/issues/341070
     def namespace_union_for_reporter_developer_maintainer_owned(select = :id)
       ::Gitlab::SQL::Union.new([
         ::Namespace.select(select).where(type: [nil, ::Namespaces::UserNamespace.sti_name], owner: self),

ee/spec/models/ee/user_spec.rb

@@ -1343,6 +1343,8 @@ RSpec.describe User do
     let_it_be(:free_group) { create(:group_with_plan, plan: :free_plan) }
     let_it_be(:group_without_plan) { create(:group) }
 
+    # TODO: this `where/when` can be removed in issue https://gitlab.com/gitlab-org/gitlab/-/issues/341070
+    #       At that point we only need to check `user_namespace`
     where(namespace_type: [:namespace, :user_namespace])
 
     with_them do

spec/models/namespace_spec.rb

@@ -178,7 +178,7 @@ RSpec.describe Namespace do
     context 'creating a Group' do
       let(:namespace_type) { group_sti_name }
 
-      it 'is valid' do
+      it 'is the correct type of namespace' do
         expect(namespace).to be_a(Group)
         expect(namespace.kind).to eq('group')
         expect(namespace.group_namespace?).to be_truthy
@@ -189,7 +189,7 @@ RSpec.describe Namespace do
       let(:namespace_type) { project_sti_name }
       let(:parent) { create(:group) }
 
-      it 'is valid' do
+      it 'is the correct type of namespace' do
         expect(Namespace.find(namespace.id)).to be_a(Namespaces::ProjectNamespace)
         expect(namespace.kind).to eq('project')
         expect(namespace.project_namespace?).to be_truthy
@@ -199,7 +199,7 @@ RSpec.describe Namespace do
     context 'creating a UserNamespace' do
       let(:namespace_type) { user_sti_name }
 
-      it 'is valid' do
+      it 'is the correct type of namespace' do
         expect(Namespace.find(namespace.id)).to be_a(Namespaces::UserNamespace)
         expect(namespace.kind).to eq('user')
         expect(namespace.user_namespace?).to be_truthy
@@ -209,7 +209,7 @@ RSpec.describe Namespace do
     context 'creating a default Namespace' do
       let(:namespace_type) { nil }
 
-      it 'is valid' do
+      it 'is the correct type of 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/user_spec.rb

@@ -2544,6 +2544,8 @@ RSpec.describe User do
   describe '.find_by_full_path' do
     using RSpec::Parameterized::TableSyntax
 
+    # TODO: this `where/when` can be removed in issue https://gitlab.com/gitlab-org/gitlab/-/issues/341070
+    #       At that point we only need to check `user_namespace`
     where(namespace_type: [:namespace, :user_namespace])
 
     with_them do