Address some suggestions from first code review

app/controllers/projects_controller.rb

@@ -3,7 +3,6 @@ class ProjectsController < Projects::ApplicationController
   include ExtractsPath
 
   before_action :authenticate_user!, except: [:index, :show, :activity, :refs]
-  before_action :namespace, only: [:new]
   before_action :project, except: [:index, :new, :create]
   before_action :repository, except: [:index, :new, :create]
   before_action :assign_ref_vars, only: [:show], if: :repo_exists?
@@ -21,7 +20,7 @@ class ProjectsController < Projects::ApplicationController
   end
 
   def new
-    build_project
+    @project ||= Project.new(params.permit(:namespace_id))
   end
 
   def edit
@@ -396,12 +395,4 @@ class ProjectsController < Projects::ApplicationController
   def project_export_enabled
     render_404 unless current_application_settings.project_export_enabled?
   end
-
-  def namespace
-    @namespace ||= Namespace.find(params[:namespace_id]) if params[:namespace_id].present?
-  end
-
-  def build_project
-    @project ||= namespace ? namespace.projects.new : Project.new
-  end
 end

app/helpers/namespaces_helper.rb

@@ -6,7 +6,6 @@ module NamespacesHelper
   def namespaces_options(selected = :current_user, display_path: false, extra_group: nil)
     groups  = current_user.owned_groups + current_user.masters_groups
     users   = [current_user.namespace]
-    options = []
 
     unless extra_group.nil? || extra_group.is_a?(Group)
       extra_group = Group.find(extra_group) if Namespace.find(extra_group).kind == 'group'
@@ -16,8 +15,9 @@ module NamespacesHelper
       groups |= [extra_group]
     end
 
-    options << options_for_group(groups, display_path)
-    options << options_for_group(users, display_path)
+    options = []
+    options << options_for_group(groups, display_path: display_path, type: 'group')
+    options << options_for_group(users, display_path: display_path, type: 'user')
 
     if selected == :current_user && current_user.namespace
       selected = current_user.namespace.id
@@ -36,13 +36,12 @@ module NamespacesHelper
 
   private
 
-  def options_for_group(namespaces, display_path)
-    type = namespaces.first.is_a?(Group) ? 'group' : 'users'
-
+  def options_for_group(namespaces, display_path:, type:)
+    group_label = type.pluralize
     elements = namespaces.sort_by(&:human_name).map! do |n|
       [display_path ? n.full_path : n.human_name, n.id,
        data: {
-         options_parent: type,
+         options_parent: group_label,
          visibility_level: n.visibility_level_value,
          visibility: n.visibility,
          name: n.name,
@@ -51,6 +50,6 @@ module NamespacesHelper
        }]
     end
 
-    [type.camelize, elements]
+    [group_label.camelize, elements]
   end
 end

app/helpers/visibility_level_helper.rb

@@ -65,7 +65,7 @@ module VisibilityLevelHelper
 
   def restricted_visibility_level_description(level)
     level_name = Gitlab::VisibilityLevel.level_name(level)
-    "#{level_name.capitalize} visibilitiy has been restricted by the administrator."
+    "#{level_name.capitalize} visibility has been restricted by the administrator."
   end
 
   def disallowed_visibility_level_description(level, form_model)
@@ -82,11 +82,11 @@ module VisibilityLevelHelper
     reasons = []
 
     unless project.visibility_level_allowed_as_fork?(level)
-      reasons << "the fork source project has lower visibility"
+      reasons << project.visibility_error_for(:fork, level: level_name)
     end
 
     unless project.visibility_level_allowed_by_group?(level)
-      reasons << "the visibility of #{project.group.name} is #{project.group.visibility}"
+      reasons << project.visibility_error_for(:group, level: level_name, group_level: project.group.visibility)
     end
 
     reasons = reasons.any? ? ' because ' + reasons.to_sentence : ''
@@ -98,15 +98,15 @@ module VisibilityLevelHelper
     reasons = []
 
     unless group.visibility_level_allowed_by_projects?(level)
-      reasons << "it contains projects with higher visibility"
+      reasons << group.visibility_error_for(:projects, level: level_name)
     end
 
     unless group.visibility_level_allowed_by_sub_groups?(level)
-      reasons << "it contains sub-groups with higher visibility"
+      reasons << group.visibility_error_for(:sub_groups, level: level_name)
     end
 
     unless group.visibility_level_allowed_by_parent?(level)
-      reasons << "the visibility of its parent group is #{group.parent.visibility}"
+      reasons << group.visibility_error_for(:parent, level: level_name, parent_level: group.parent.visibility)
     end
 
     reasons = reasons.any? ? ' because ' + reasons.to_sentence : ''

app/models/group.rb

@@ -26,7 +26,7 @@ class Group < Namespace
 
   validate :avatar_type, if: ->(user) { user.avatar.present? && user.avatar_changed? }
   validate :visibility_level_allowed_by_projects
-  validate :visibility_level_allowed_by_sub_groups, if: :visibility_level_changed?
+  validate :visibility_level_allowed_by_sub_groups
   validate :visibility_level_allowed_by_parent
 
   validates :avatar, file_size: { maximum: 200.kilobytes.to_i }
@@ -104,24 +104,6 @@ class Group < Namespace
     full_name
   end
 
-  def visibility_level_allowed_by_parent
-    return if visibility_level_allowed_by_parent?
-
-    errors.add(:visibility_level, "#{visibility} is not allowed since the parent group has a #{parent.visibility} visibility.")
-  end
-
-  def visibility_level_allowed_by_projects
-    return if visibility_level_allowed_by_projects?
-
-    errors.add(:visibility_level, "#{visibility} is not allowed since this group contains projects with higher visibility.")
-  end
-
-  def visibility_level_allowed_by_sub_groups
-    return if visibility_level_allowed_by_sub_groups?
-
-    errors.add(:visibility_level, "#{visibility} is not allowed since there are sub-groups with higher visibility.")
-  end
-
   def visibility_level_allowed_by_parent?(level = self.visibility_level)
     return true unless parent_id && parent_id.nonzero?
 
@@ -304,11 +286,29 @@ class Group < Namespace
     list_of_ids.reverse.map { |group| variables[group.id] }.compact.flatten
   end
 
-  protected
+  private
 
   def update_two_factor_requirement
     return unless require_two_factor_authentication_changed? || two_factor_grace_period_changed?
 
     users.find_each(&:update_two_factor_requirement)
   end
+
+  def visibility_level_allowed_by_parent
+    return if visibility_level_allowed_by_parent?
+
+    errors.add(:visibility_level, visibility_error_for(:parent, level: visibility, parent_level: parent.visibility))
+  end
+
+  def visibility_level_allowed_by_projects
+    return if visibility_level_allowed_by_projects?
+
+    errors.add(:visibility_level, visibility_error_for(:projects, level: visibility))
+  end
+
+  def visibility_level_allowed_by_sub_groups
+    return if visibility_level_allowed_by_sub_groups?
+
+    errors.add(:visibility_level, visibility_error_for(:sub_groups, level: visibility))
+  end
 end

app/models/project.rb

@@ -671,14 +671,16 @@ class Project < ActiveRecord::Base
 
     level_name = Gitlab::VisibilityLevel.level_name(self.visibility_level).downcase
     group_level_name = Gitlab::VisibilityLevel.level_name(self.group.visibility_level).downcase
-    self.errors.add(:visibility_level, "#{level_name} is not allowed in a #{group_level_name} group.")
+
+    self.errors.add(:visibility_level, visibility_error_for(:group, level: level_name, group_level: group_level_name))
   end
 
   def visibility_level_allowed_as_fork
     return if visibility_level_allowed_as_fork?
 
     level_name = Gitlab::VisibilityLevel.level_name(self.visibility_level).downcase
-    self.errors.add(:visibility_level, "#{level_name} is not allowed since the fork source project has lower visibility.")
+
+    self.errors.add(:visibility_level, visibility_error_for(:fork, level: level_name))
   end
 
   def check_wiki_path_conflict

lib/gitlab/visibility_level.rb

@@ -130,5 +130,23 @@ module Gitlab
     def visibility=(level)
       self[visibility_level_field] = Gitlab::VisibilityLevel.level_value(level)
     end
+
+    def visibility_errors_template
+      @visibility_errors ||= {
+        'Project' => {
+          group: "%{level} is not allowed in a %{group_level} group",
+          fork: "%{level} is not allowed since the fork source project has lower visibility"
+        },
+        'Group' => {
+          parent: "%{level} is not allowed since the parent group has a %{parent_level} visibility",
+          projects: "%{level} is not allowed since this group contains projects with higher visibility",
+          sub_groups: "%{level} is not allowed since there are sub-groups with higher visibility"
+        }
+      }
+    end
+
+    def visibility_error_for(section, variables)
+      visibility_errors_template.dig(model_name.to_s, section) % variables
+    end
   end
 end