Change unique indexes for form documents to allow for multiple versions

db/migrate/20260813112443_change_unique_indexes_on_form_documents.rb

@@ -0,0 +1,19 @@
+class ChangeUniqueIndexesOnFormDocuments < ActiveRecord::Migration[8.1]
+  def up
+    remove_index :form_documents, name: "index_form_documents_on_form_id_tag_and_language"
+
+    # Only one form_document with the same version per language per form
+    add_index :form_documents, %i[form_id version language], name: "index_form_documents_on_form_id_version_and_language", unique: true
+
+    # Only one form_document with a null version (the draft form document) per language per form
+    add_index :form_documents, %i[form_id language], name: "index_form_documents_only_one_draft_per_language", unique: true, where: "version IS NULL"
+  end
+
+  def down
+    remove_index :form_documents, name: "index_form_documents_only_one_draft_per_language"
+
+    remove_index :form_documents, name: "index_form_documents_on_form_id_version_and_language"
+
+    add_index :form_documents, %i[form_id tag language], name: "index_form_documents_on_form_id_tag_and_language", unique: true
+  end
+end

spec/models/form_document_spec.rb

@@ -46,8 +46,23 @@
     expect(form_document.form).to be_a(Form)
   end
 
-  it "tags must be unique for a given form" do
-    form_document = create(:form_document, tag: "live")
-    expect { create(:form_document, form: form_document.form, tag: "live") }.to raise_error(ActiveRecord::RecordNotUnique)
+  it "raises an error if a form document with the same version exists for the form" do
+    form_document = create(:form_document, :live, version: 1)
+    expect { create(:form_document, :archived, form: form_document.form, version: 1) }.to raise_error(ActiveRecord::RecordNotUnique)
+  end
+
+  it "raises an error if a draft form document already exists for the form" do
+    form = create(:form) # also creates a draft form document
+    expect { create(:form_document, :draft, form: form) }.to raise_error(ActiveRecord::RecordNotUnique)
+  end
+
+  it "allows creating a form with the same version and a different language" do
+    form_document = create(:form_document, :live, language: "en")
+    expect { create(:form_document, :live, form: form_document.form, language: "cy") }.not_to raise_error
+  end
+
+  it "allows creating a draft form with a different language" do
+    form = create(:form) # also creates a draft form document
+    expect { create(:form_document, :draft, form: form, language: "cy") }.not_to raise_error
   end
 end

spec/requests/api/form_documents_controller_spec.rb

@@ -123,8 +123,8 @@
       let(:form) { create :form }
 
       before do
-        create :form_document, form: form, tag: "live", language: "en", content: { form_id: form.id.to_s, language: "en" }
-        create :form_document, form: form, tag: "live", language: "cy", content: { form_id: form.id.to_s, language: "cy" }
+        create :form_document, :live, form: form, language: "en", content: { form_id: form.id.to_s, language: "en" }
+        create :form_document, :live, form: form, language: "cy", content: { form_id: form.id.to_s, language: "cy" }
       end
 
       it "when not given a language, defaults to english returns the live form document in english" do

spec/services/revert_draft_form_service_spec.rb

@@ -95,7 +95,7 @@ def revert_draft(tag)
           goto_page_id: live_form.pages.last.id,
           routing_page_id: live_form.pages.first.id,
         )
-        FormDocument.create!(form: live_form, tag: "live", content: live_form.as_form_document(live_at: live_form.updated_at))
+        create(:form_document, :live, form: live_form, content: live_form.as_form_document(live_at: live_form.updated_at))
         live_form.update!(state: :live_with_draft)
       end
 
@@ -149,7 +149,7 @@ def revert_draft(tag)
           exit_page_heading: "You cannot continue",
           exit_page_markdown: "Please contact us",
         )
-        FormDocument.create!(form: live_form, tag: "live", content: live_form.as_form_document(live_at: live_form.updated_at))
+        create(:form_document, :live, form: live_form, content: live_form.as_form_document(live_at: live_form.updated_at))
         live_form.update!(state: :live_with_draft)
       end
 
@@ -563,7 +563,7 @@ def revert_draft(tag)
           goto_page_id: archived_form.pages.last.id,
           routing_page_id: archived_form.pages.first.id,
         )
-        FormDocument.create!(form: archived_form, tag: "archived", content: archived_form.as_form_document(live_at: archived_form.updated_at))
+        create(:form_document, :archived, form: archived_form, content: archived_form.as_form_document(live_at: archived_form.updated_at))
         archived_form.update!(state: :archived_with_draft)
       end