Capture same base path error and display to user

Instead of presenting a server error to the user if they try and create
an edition that has the base path of another published edition, the
error is now presented to the user.

Author: ChrisBAshton

app/controllers/admin/editions_controller.rb

@@ -97,6 +97,7 @@ def create
     @edition.destroy!
     build_edition
     build_edition_dependencies
+    @edition.errors.add(:title, "has been used before on GOV.UK, although the page may no longer exist. Please use another title")
     render :new
   end
 

app/models/document.rb

@@ -85,7 +85,6 @@ def first_edition_id
 
   def similar_slug_exists?
     scope = Document.where(document_type:)
-    sequence_separator = friendly_id_config.sequence_separator
 
     # slug is a nullable column, so we can't assume that it exists
     return false if slug.nil?
@@ -99,6 +98,8 @@ def similar_slug_exists?
     ).count > 1
   end
 
+  delegate :sequence_separator, to: :friendly_id_config
+
   def should_generate_new_friendly_id?
     sluggable_string.present?
   end

app/models/edition.rb

@@ -402,6 +402,10 @@ def base_path
     "/government/generic-editions/#{url_slug}"
   end
 
+  def base_path_without_sequence
+    base_path.split(document.sequence_separator).first
+  end
+
   def public_path(options = {})
     return if base_path.nil?
 

features/standard-edition.feature

@@ -57,3 +57,12 @@ Feature: Standard Editions
     And choosing a document type should take me to a preview page summarising the changes
     And when I click "Confirm document type change"
     Then the document type should have updated
+
+  Scenario: Creating a new draft configurable document with the same base path as an already published configurable document
+    Given I am a writer
+    And the configurable document types feature flag is enabled
+    And the test configurable document type is defined
+    And I have published a configurable document titled "The history of GOV.UK"
+    When I draft a new "Test configurable document type" configurable document with the same title as a published edition
+    Then I should see an error of "Title has been used before on GOV.UK, although the page may no longer exist. Please use another title" on the new configurable document page
+    And the form should retain the user input with the title "The history of GOV.UK" before submit

features/step_definitions/standard_edition_steps.rb

@@ -77,6 +77,29 @@ def default_content_for_locale(locale)
   click_button "Save and go to document summary"
 end
 
+When(/^I draft a new "([^"]*)" configurable document with the same title as a published edition$/) do |configurable_document_type|
+  create(:organisation) if Organisation.count.zero?
+  visit admin_root_path
+  find("li.app-c-sub-navigation__list-item a", text: "New document").click
+  page.choose("Standard document")
+  click_button("Next")
+  page.choose(configurable_document_type)
+  click_button("Next")
+  expect(page).to have_content("New test")
+  within "form" do
+    fill_in "edition_title", with: Edition.published.first.title
+    fill_in "edition_summary", with: "A brief summary of the document."
+    fill_in "edition_body", with: "## Some govspeak This is the body content"
+    fill_in "edition[block_content][date_field][3]", with: "01"
+    fill_in "edition[block_content][date_field][2]", with: "11"
+    fill_in "edition[block_content][date_field][1]", with: "2011"
+  end
+  Whitehall::PublishingApi.unstub(:ensure_base_path_is_associated_with_this_content_id!)
+  Services.publishing_api.stubs(:lookup_content_id).returns("not a real content id")
+  click_button "Save and go to document summary"
+  Whitehall::PublishingApi.stubs(:ensure_base_path_is_associated_with_this_content_id!).returns(nil)
+end
+
 Then("when I switch to the Images tab to fill in the other configurable fields") do
   # Pretend we've uploaded an image already
   edition = @standard_edition || StandardEdition.last
@@ -308,6 +331,22 @@ def default_content_for_locale(locale)
   end
 end
 
+Given(/^I have published a configurable document titled "([^"]*)"$/) do |title|
+  en_content = default_content_for_locale("en")
+  @standard_edition = create(
+    :published_standard_edition,
+    {
+      configurable_document_type: "test",
+      title: title || en_content[:title],
+      summary: en_content[:summary],
+      block_content: {
+        "body" => en_content[:body],
+        "date_field" => en_content[:date_field],
+      },
+    },
+  )
+end
+
 When(/^I create a new draft and visit the Welsh translation$/) do
   edition = @standard_edition || StandardEdition.last
   visit admin_standard_edition_path(edition)
@@ -380,3 +419,17 @@ def default_content_for_locale(locale)
 
   expect(page).to have_content("Test configurable document type two")
 end
+
+Then(/^I should see an error of "(.*)" on the new configurable document page$/) do |error|
+  expect(page).to have_selector(".gem-c-error-summary__list-item")
+  expect(page).to have_content(error.to_s)
+end
+
+And(/^the form should retain the user input with the title "(.*)" before submit$/) do |title|
+  expect(page).to have_field("Title", with: title)
+  expect(page).to have_field("Summary", with: "A brief summary of the document.")
+  expect(page).to have_field("Body", with: "## Some govspeak This is the body content")
+  expect(page).to have_field("Day", with: "01")
+  expect(page).to have_field("Month", with: "11")
+  expect(page).to have_field("Year", with: "2011")
+end

features/support/document_helper.rb

@@ -21,6 +21,11 @@ def begin_drafting_document(options)
     page.choose(options[:type].humanize)
     click_button("Next")
 
+    if options[:subtype]
+      page.choose(options[:subtype].humanize)
+      click_button("Next")
+    end
+
     if options[:locale]
       check "Create a foreign language only"
       select options[:locale], from: "Document language"

lib/whitehall/publishing_api.rb

@@ -69,7 +69,7 @@ def self.save_draft_translation(
 
         content.merge!(bulk_publishing: true) if bulk_publishing
 
-        ensure_base_path_is_associated_with_this_content_id!(content[:base_path], model_instance.content_id)
+        ensure_base_path_is_associated_with_this_content_id!(model_instance, content)
 
         Services.publishing_api.put_content(presenter.content_id, content)
       end
@@ -181,7 +181,18 @@ def self.assert_public_edition!(instance)
       end
     end
 
-    def self.ensure_base_path_is_associated_with_this_content_id!(base_path, content_id)
+    def self.ensure_base_path_is_associated_with_this_content_id!(instance, content)
+      content_id = instance.content_id
+
+      base_path = if instance.respond_to?(:base_path_without_sequence)
+                    # `base_path_without_sequence` required because if an edition with the same
+                    # title exists in Whitehall then `base_path` of `instance` will have
+                    # a unique sequence identifier and the check will not work as intended
+                    instance.base_path_without_sequence
+                  else
+                    content[:base_path]
+                  end
+
       existing_content_id = Services.publishing_api.lookup_content_id(base_path:)
       return if existing_content_id.nil? || existing_content_id == content_id
 

test/unit/app/models/edition_test.rb

@@ -945,6 +945,14 @@ class EditionTest < ActiveSupport::TestCase
     assert edition.reload.revalidated_at
   end
 
+  test "#base_path_without_sequence should return base path without unique identifier " do
+    existing = create(:edition, title: "Latest news")
+    draft = create(:edition, title: "Latest news")
+
+    assert_not_equal draft.base_path, existing.base_path
+    assert_equal draft.base_path_without_sequence, existing.base_path
+  end
+
   def decoded_token_payload(token)
     payload, _header = JWT.decode(
       token,