Rule 4: Parent visibility ceiling

A child document may not be more publicly visible than its parent document.

| Parent      | Allowed child states                |
|-------------|-------------------------------------|
| published   | published / withdrawn / unpublished |
| withdrawn   | withdrawn / unpublished             |
| unpublished | unpublished                         |

Implementation wise, we **could** auto-cascade such that if you unpublish the parent, you unpublish its children. But it gets messy if there exists a draft child - do you auto-discard the draft in order to unpublish it? Etc. So to begin with at least, we will force the publisher to manually withdraw/unpublish (as appropriate) all of a document's children before withdrawing/unpublishing the parent document. This simplified interpretation can be summarised as "You cannot withdraw/unpublish a parent while any children remain more publicly visible than it."

Author: ChrisBAshton

app/controllers/admin/edition_workflow_controller.rb

@@ -114,6 +114,8 @@ def unpublish
       flash.now[:alert] = message if @unpublishing.errors.blank?
       render :confirm_unpublish
     end
+  rescue WhitehallError => e
+    redirect_to admin_edition_path(@edition), alert: e.message
   end
 
   def confirm_unwithdraw; end

app/models/concerns/standard_edition/parent_document.rb

@@ -2,6 +2,8 @@ module StandardEdition::ParentDocument
   extend ActiveSupport::Concern
 
   class UnableToDelete < ::WhitehallError; end
+  class UnableToWithdraw < ::WhitehallError; end
+  class UnableToUnpublish < ::WhitehallError; end
 
   class Trait < Edition::Traits::Trait
     def process_associations_after_save(new_edition)
@@ -33,6 +35,7 @@ def process_associations_after_save(new_edition)
              source: :child_document
 
     before_update :ensure_no_new_child_documents!, if: :deleting?
+    before_update :ensure_no_children_more_visible_than_parent!, if: :will_save_change_to_state?
 
     add_trait Trait
   end
@@ -64,4 +67,14 @@ def ensure_no_new_child_documents!
       raise UnableToDelete, "This document cannot be deleted while it has child documents that have never been published. Delete the draft child documents first."
     end
   end
+
+  def ensure_no_children_more_visible_than_parent!
+    if state == "unpublished" && child_editions.any? { |child| child.state.in?(%w[published withdrawn]) }
+      raise UnableToUnpublish, "This document cannot be unpublished while it has child documents that are published or withdrawn. Unpublish the child documents first."
+    end
+
+    if state == "withdrawn" && child_editions.any? { |child| child.state == "published" }
+      raise UnableToWithdraw, "This document cannot be withdrawn while it has child documents that are published. Withdraw the child documents first."
+    end
+  end
 end

test/functional/admin/edition_workflow_controller_test.rb

@@ -388,6 +388,18 @@ class Admin::EditionWorkflowControllerTest < ActionController::TestCase
     assert published_edition.reload.published?
   end
 
+  test "#unpublish catches WhitehallError and redirects with an alert" do
+    Whitehall.edition_services.stubs(:unpublisher).raises(WhitehallError.new("Something went wrong"))
+    login_as create(:managing_editor)
+    unpublish_params = {
+      unpublishing_reason_id: UnpublishingReason::Consolidated.id,
+      alternative_url: "https://www.gov.uk/alternative",
+    }
+    post :unpublish, params: { id: published_edition, lock_version: published_edition.lock_version, unpublishing: unpublish_params }
+    assert_redirected_to admin_publication_path(published_edition)
+    assert_equal "Something went wrong", flash[:alert]
+  end
+
   view_test "#unpublish when there are validation errors re-renders the unpublish form" do
     login_as create(:managing_editor)
     unpublish_params = {

test/unit/app/models/concerns/standard_edition/parent_document_test.rb

@@ -239,4 +239,87 @@ class StandardEdition::ParentDocumentTest < ActiveSupport::TestCase
 
     assert_equal "This document cannot be deleted while it has child documents that have never been published. Delete the draft child documents first.", error.message
   end
+
+  test "able to unpublish parent edition if all of its children are already unpublished" do
+    parent_edition = create(:standard_edition)
+
+    child_edition = create(:unpublished_standard_edition)
+    build(
+      :parent_child_relationship,
+      parent_edition: parent_edition,
+      child_document: child_edition.document,
+    ).save!(validate: false)
+
+    assert_nothing_raised do
+      parent_edition.update!(state: "unpublished")
+    end
+  end
+
+  test "able to withdraw parent edition if all of its children are already unpublished or withdrawn" do
+    parent_edition = create(:standard_edition)
+    child_edition_1 = create(:unpublished_standard_edition)
+    child_edition_2 = create(:withdrawn_standard_edition)
+    [child_edition_1, child_edition_2].each do |child_edition|
+      build(
+        :parent_child_relationship,
+        parent_edition: parent_edition,
+        child_document: child_edition.document,
+      ).save!(validate: false)
+    end
+
+    assert_nothing_raised do
+      parent_edition.update!(state: "withdrawn")
+    end
+  end
+
+  test "unable to unpublish parent edition if it contains any published child documents" do
+    parent_edition = create(:standard_edition)
+
+    child_edition = create(:published_standard_edition)
+    build(
+      :parent_child_relationship,
+      parent_edition: parent_edition,
+      child_document: child_edition.document,
+    ).save!(validate: false)
+
+    error = assert_raises(StandardEdition::ParentDocument::UnableToUnpublish) do
+      parent_edition.update!(state: "unpublished")
+    end
+
+    assert_equal "This document cannot be unpublished while it has child documents that are published or withdrawn. Unpublish the child documents first.", error.message
+  end
+
+  test "unable to unpublish parent edition if it contains any withdrawn child documents" do
+    parent_edition = create(:standard_edition)
+
+    child_edition = create(:withdrawn_standard_edition)
+    build(
+      :parent_child_relationship,
+      parent_edition: parent_edition,
+      child_document: child_edition.document,
+    ).save!(validate: false)
+
+    error = assert_raises(StandardEdition::ParentDocument::UnableToUnpublish) do
+      parent_edition.update!(state: "unpublished")
+    end
+
+    assert_equal "This document cannot be unpublished while it has child documents that are published or withdrawn. Unpublish the child documents first.", error.message
+  end
+
+  test "unable to withdraw parent edition if it contains any published child documents" do
+    parent_edition = create(:standard_edition)
+
+    child_edition = create(:published_standard_edition)
+    build(
+      :parent_child_relationship,
+      parent_edition: parent_edition,
+      child_document: child_edition.document,
+    ).save!(validate: false)
+
+    error = assert_raises(StandardEdition::ParentDocument::UnableToWithdraw) do
+      parent_edition.update!(state: "withdrawn")
+    end
+
+    assert_equal "This document cannot be withdrawn while it has child documents that are published. Withdraw the child documents first.", error.message
+  end
 end