AI: address review on PR #469

backend/app/models/post_implication.rb

@@ -8,6 +8,7 @@ class PostImplication < ApplicationRecord
   validates :parent_post_id, presence: true
 
   validate :parent_post_mustnt_be_itself
+  validate :parent_post_mustnt_create_cycle
 
   private
 
@@ -16,4 +17,24 @@ class PostImplication < ApplicationRecord
       errors.add :parent_post_id, '親投稿に同じ投稿を設定することはできません．'
     end
   end
+
+  def parent_post_mustnt_create_cycle
+    return if post_id.blank? || parent_post_id.blank?
+    return if errors[:parent_post_id].present?
+
+    ancestor_ids = Set.new
+    frontier_ids = [parent_post_id]
+
+    until frontier_ids.empty?
+      if frontier_ids.include?(post_id)
+        errors.add :parent_post_id, :invalid
+        return
+      end
+
+      ancestor_ids.merge(frontier_ids)
+      frontier_ids = PostImplication.where(post_id: frontier_ids)
+          .distinct.pluck(:parent_post_id)
+          .reject { ancestor_ids.include?(_1) }
+    end
+  end
 end

backend/spec/models/post_implication_spec.rb

@@ -48,4 +48,47 @@ RSpec.describe PostImplication, type: :model do
     expect(duplicate).not_to be_valid
     expect(duplicate.errors[:post_id]).to be_present
   end
+
+  it 'rejects a parent that would create a two-post cycle' do
+    described_class.create!(post: post_record, parent_post:)
+
+    implication = described_class.new(
+        post: parent_post, parent_post: post_record)
+
+    expect(implication).not_to be_valid
+    expect(implication.errors.of_kind?(:parent_post_id, :invalid)).to be true
+  end
+
+  it 'rejects a parent that would create a three-post cycle' do
+    ancestor_post = create(:post)
+    described_class.create!(post: post_record, parent_post:)
+    described_class.create!(post: parent_post, parent_post: ancestor_post)
+
+    implication = described_class.new(
+        post: ancestor_post, parent_post: post_record)
+
+    expect(implication).not_to be_valid
+    expect(implication.errors.of_kind?(:parent_post_id, :invalid)).to be true
+  end
+
+  it 'allows a parent with an ancestor when no cycle would result' do
+    ancestor_post = create(:post)
+    described_class.create!(post: parent_post, parent_post: ancestor_post)
+
+    implication = described_class.new(post: post_record, parent_post:)
+
+    expect(implication).to be_valid
+  end
+
+  it 'terminates when existing ancestors already contain a cycle' do
+    ancestor_post = create(:post)
+    described_class.create!(post: parent_post, parent_post: ancestor_post)
+    legacy_implication = described_class.new(
+        post: ancestor_post, parent_post:)
+    legacy_implication.save!(validate: false)
+
+    implication = described_class.new(post: post_record, parent_post:)
+
+    expect(implication).to be_valid
+  end
 end

frontend/src/components/DraggableDroppableTagRow.test.tsx

@@ -1,25 +1,9 @@
-import { screen } from '@testing-library/react'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 import DraggableDroppableTagRow from '@/components/DraggableDroppableTagRow'
 import { buildTag } from '@/test/factories'
 import { renderWithProviders } from '@/test/render'
 
-import type { CSSProperties, ReactNode } from 'react'
-
-vi.mock ('framer-motion', async importOriginal => {
-  const original = await importOriginal<typeof import ('framer-motion')> ()
-  return {
-      ...original,
-      motion: {
-	  ...original.motion,
-	  div: ({ children, style, layoutId }: {
-	      children?: ReactNode
-	      style?: CSSProperties
-	      layoutId?: string }) => (
-	      <div style={style} data-layout-id={layoutId}>{children}</div>) } }
-})
-
 const dndKit = vi.hoisted (() => ({
   useDraggable: vi.fn (),
   useDroppable: vi.fn (),
@@ -113,32 +97,4 @@ describe ('DraggableDroppableTagRow', () => {
 	}),
     )
   })
-
-  it.each ([false, true]) (
-      'separates same-id internal and external animation identities (sp=%s)',
-      sp => {
-	const internal = buildTag ({ id: 7, name: 'internal_collision' })
-	const external = buildTag ({
-	    id: 7, name: 'nico:external_collision', category: 'nico' })
-
-	renderWithProviders (
-	    <>
-	      {[internal, external].map (item => (
-		  <DraggableDroppableTagRow
-		      key={item.category}
-		      tag={item}
-		      nestLevel={0}
-		      pathKey={`cat-${ item.category }-7`}
-		      suppressClickRef={{ current: false }}
-		      sp={sp}/>))}
-	    </>)
-
-	const prefix = sp ? 'tag-sp-' : 'tag-'
-	for (const item of [internal, external])
-	{
-	  expect (screen.getByRole ('link', { name: item.name })
-	      .closest ('[data-layout-id]')).toHaveAttribute (
-		  'data-layout-id', `${ prefix }${ item.category }-7`)
-	}
-      })
 })

frontend/src/components/DraggableDroppableTagRow.tsx

@@ -137,7 +137,7 @@ const DraggableDroppableTagRow: FC<Props> = ({
 		transition={{ layout: layoutTransition }}
 		layoutId={animationMode === 'off'
 		    ? undefined
-		    : `tag-${ sp ? 'sp-' : '' }${ tag.category }-${ tag.id }`}>
+		    : `tag-${ sp ? 'sp-' : '' }${ tag.id }`}>
 	      <TagLink tag={tag} nestLevel={nestLevel}/>
 	    </motion.div>)}
       </div>)

frontend/src/components/TagSidebar.test.tsx

@@ -1,47 +0,0 @@
-import { screen } from '@testing-library/react'
-import { describe, expect, it, vi } from 'vitest'
-
-import TagSidebar from '@/components/TagSidebar'
-import { buildPost, buildTag } from '@/test/factories'
-import { renderWithProviders } from '@/test/render'
-
-import type { ReactNode } from 'react'
-
-vi.mock ('@/components/TagSearch', () => ({ default: () => null }))
-vi.mock ('@/components/layout/SidebarComponent', () => ({
-    default: ({ children }: { children: ReactNode }) => <>{children}</> }))
-
-vi.mock ('framer-motion', async importOriginal => {
-  const original = await importOriginal<typeof import ('framer-motion')> ()
-  return {
-      ...original,
-      motion: {
-	  ...original.motion,
-	  div: ({ children, layoutId }: {
-	      children?: ReactNode
-	      layoutId?: string }) => (
-	      <div data-layout-id={layoutId}>{children}</div>) } }
-})
-
-describe ('TagSidebar', () => {
-  it ('keeps same-id internal and external tags with distinct identities', () => {
-    const errors = vi.spyOn (console, 'error').mockImplementation (() => {})
-    const internal = buildTag ({ id: 7, name: 'internal_collision' })
-    const external = buildTag ({
-	id: 7, name: 'nico:external_collision', category: 'nico' })
-
-    renderWithProviders (
-	<TagSidebar posts={[buildPost ({ tags: [internal, external] })]}/>)
-
-    for (const item of [internal, external])
-    {
-      const link = screen.getByRole ('link', { name: item.name })
-      expect (link).toBeInTheDocument ()
-      expect (link.closest ('[data-layout-id]')).toHaveAttribute (
-	  'data-layout-id', `tag-${ item.category }-7`)
-    }
-
-    expect (errors.mock.calls.filter (args =>
-	args.some (value => String (value).includes ('same key')))).toEqual ([])
-  })
-})

frontend/src/components/TagSidebar.tsx

@@ -84,8 +84,7 @@ const TagSidebar: FC<Props> = ({ posts, onClick }) => {
 	<ul>
 	  {CATEGORIES.flatMap (cat => cat in tags ? (
 	      tags[cat].map (tag => (
-		  <li key={`${ cat }-${ tag.id }`}
-		      className="mb-1 min-w-0 max-w-full overflow-hidden">
+		  <li key={tag.id} className="mb-1 min-w-0 max-w-full overflow-hidden">
 		    {animationsOff
 		     ? (
 			 <div className="flex min-w-0 max-w-full items-baseline overflow-hidden">
@@ -95,7 +94,7 @@ const TagSidebar: FC<Props> = ({ posts, onClick }) => {
 			 <motion.div
 			     className="flex min-w-0 max-w-full items-baseline overflow-hidden"
 			     transition={{ layout: layoutTransition }}
-			     layoutId={`tag-${ cat }-${ tag.id }`}>
+			     layoutId={`tag-${ tag.id }`}>
 			   <TagLink tag={tag} onClick={onClick}/>
 			 </motion.div>)}
 		  </li>))) : [])}