#389

Reviewed-on: #382

backend/app/models/tag_implication.rb

@@ -6,6 +6,7 @@ class TagImplication < ApplicationRecord
   validates :parent_tag_id, presence: true
 
   validate :parent_tag_mustnt_be_itself
+  validate :parent_tag_mustnt_create_cycle
 
   private
 
@@ -14,4 +15,27 @@ class TagImplication < ApplicationRecord
       errors.add :parent_tag_id, '親タグは子タグと同一であってはなりません．'
     end
   end
+
+  def parent_tag_mustnt_create_cycle
+    return if tag_id.blank? || parent_tag_id.blank?
+    return if errors[:parent_tag_id].present?
+
+    seen = { }
+    stack = [parent_tag_id]
+
+    until stack.empty?
+      current_id = stack.pop
+      next if seen[current_id]
+
+      seen[current_id] = true
+
+      if current_id == tag_id
+        errors.add :parent_tag_id, '親タグに子孫タグを指定すると循環します．'
+        errors.add :base, 'タグの親子関係が循環します．'
+        return
+      end
+
+      stack.concat(TagImplication.where(tag_id: current_id).pluck(:parent_tag_id))
+    end
+  end
 end

backend/spec/models/tag_implication_spec.rb

@@ -0,0 +1,36 @@
+require 'rails_helper'
+
+RSpec.describe TagImplication, type: :model do
+  it 'rejects a parent tag that would create a cycle' do
+    child = create(:tag, name: 'tag_implication_cycle_child')
+    parent = create(:tag, name: 'tag_implication_cycle_parent')
+
+    described_class.create!(tag: child, parent_tag: parent)
+
+    implication = described_class.new(tag: parent, parent_tag: child)
+
+    expect(implication).not_to be_valid
+    expect(implication.errors[:parent_tag_id]).to include(
+      '親タグに子孫タグを指定すると循環します．'
+    )
+    expect(implication.errors[:base]).to be_present
+  end
+
+  it 'terminates even when existing data already contains a cycle' do
+    child = create(:tag, name: 'tag_implication_existing_cycle_child')
+    parent = create(:tag, name: 'tag_implication_existing_cycle_parent')
+    ancestor = create(:tag, name: 'tag_implication_existing_cycle_ancestor')
+
+    described_class.create!(tag: parent, parent_tag: ancestor)
+    described_class.insert_all!(
+      [
+        { tag_id: ancestor.id, parent_tag_id: parent.id,
+          created_at: Time.current, updated_at: Time.current }
+      ]
+    )
+
+    implication = described_class.new(tag: child, parent_tag: parent)
+
+    expect(implication).to be_valid
+  end
+end

backend/spec/models/tag_spec.rb

@@ -54,7 +54,17 @@ RSpec.describe Tag, type: :model do
       first = create(:tag, name: 'expand_cycle_first')
       second = create(:tag, name: 'expand_cycle_second')
       TagImplication.create!(tag: first, parent_tag: second)
-      TagImplication.create!(tag: second, parent_tag: first)
+      now = Time.current
+      TagImplication.insert_all!(
+        [
+          {
+            tag_id: second.id,
+            parent_tag_id: first.id,
+            created_at: now,
+            updated_at: now
+          }
+        ]
+      )
 
       expect(described_class.expand_parent_tags([first])).to contain_exactly(first, second)
     end

backend/spec/requests/tag_children_spec.rb

@@ -56,6 +56,17 @@ RSpec.describe "TagChildren", type: :request do
 
         expect(response).to have_http_status(:no_content)
       end
+
+      it 'returns 422 and does not create relation when the new link makes a cycle' do
+        TagImplication.create!(tag: parent, parent_tag: child)
+
+        expect {
+          do_request
+        }.not_to change(TagImplication, :count)
+
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(TagImplication.where(tag: child, parent_tag: parent)).not_to exist
+      end
     end
 
     context "when Tag.find raises (invalid ids)" do

backend/spec/requests/tags_spec.rb

@@ -797,7 +797,17 @@ RSpec.describe 'Tags API', type: :request do
       )
       TagImplication.create!(tag: first, parent_tag: root_material)
       TagImplication.create!(tag: second, parent_tag: first)
-      TagImplication.create!(tag: first, parent_tag: second)
+      now = Time.current
+      TagImplication.insert_all!(
+        [
+          {
+            tag_id: first.id,
+            parent_tag_id: second.id,
+            created_at: now,
+            updated_at: now
+          }
+        ]
+      )
 
       get '/tags/with-depth', params: { parent: root_material.id }
 
@@ -1364,8 +1374,6 @@ RSpec.describe 'Tags API', type: :request do
       end
 
       it 'parent_tags に指定すると循環する tag は 422 にする' do
-        pending '#332 で対応予定'
-
         child = Tag.create!(
           tag_name: TagName.create!(name: 'put_cycle_child'),
           category: :general

frontend/src/App.tsx

@@ -6,6 +6,7 @@ import { BrowserRouter,
 	 Routes,
 	 useLocation } from 'react-router-dom'
 
+import DevModeWatermark from '@/components/DevModeWatermark'
 import RouteBlockerOverlay from '@/components/RouteBlockerOverlay'
 import TopNav from '@/components/TopNav'
 import DialogueProvider from '@/components/dialogues/DialogueProvider'
@@ -145,6 +146,7 @@ const App: FC = () => {
   return (
       <>
 	<RouteBlockerOverlay/>
+	{import.meta.env.DEV && <DevModeWatermark/>}
 
 	<BrowserRouter>
 	  <DialogueProvider>
@@ -152,7 +154,7 @@ const App: FC = () => {
 	      <motion.div
 		  layout="position"
 		  transition={{ layout: { duration: .2, ease: 'easeOut' } }}
-		  className="flex flex-col h-dvh w-full overflow-y-hidden">
+		  className="relative flex flex-col h-dvh w-full overflow-y-hidden">
 		<TopNav user={user}/>
 		<RouteTransitionWrapper user={user} setUser={setUser}/>
 	      </motion.div>

frontend/src/components/DevModeWatermark.tsx

@@ -0,0 +1,46 @@
+import nikumaru from '@/assets/fonts/nikumaru.otf'
+
+import type { FC } from 'react'
+
+
+const ROW_COUNT = 8
+const COLUMN_COUNT = 12
+
+
+const DevModeWatermark: FC = () => {
+  return (
+      <div
+	  aria-hidden="true"
+	  className="pointer-events-none select-none fixed inset-0 overflow-hidden z-0">
+	<style>{`
+	  @font-face {
+	    font-family: 'Nikumaru';
+	    src: url(${nikumaru}) format('opentype');
+	  }
+	`}</style>
+	<div className="absolute -inset-32 flex flex-col justify-center gap-12 py-48">
+	  {Array.from ({ length: ROW_COUNT }, (_, rowIndex) => (
+	      <div
+		  key={rowIndex}
+		  className={
+		      'flex min-h-32 items-center gap-12 '
+		      + (rowIndex % 2 === 0 ? 'translate-x-0' : 'translate-x-32')
+		  }>
+		{Array.from ({ length: COLUMN_COUNT }, (_, columnIndex) => (
+		    <span
+			key={columnIndex}
+			className={
+			    'whitespace-nowrap text-3xl font-bold '
+			    + 'tracking-[0.3em] text-neutral-950/5 '
+			    + 'dark:text-white/10'
+			}
+			style={{ fontFamily: 'Nikumaru' }}>
+		      開発モード
+		    </span>))}
+	      </div>))}
+	</div>
+      </div>)
+}
+
+
+export default DevModeWatermark