#419

backend/spec/requests/tags_spec.rb

@@ -396,7 +396,9 @@ RSpec.describe 'Tags API', type: :request do
     end
 
     it 'prefers Tag when Tag and ExternalTag have the same id' do
-      internal = create(:tag, name: 'internal_collision')
+      internal = create(
+          :tag,
+          tag_name: create(:tag_name, name: 'internal_collision'))
       create(
           :external_tag,
           id: internal.id,
@@ -407,8 +409,8 @@ RSpec.describe 'Tags API', type: :request do
       expect(response).to have_http_status(:ok)
       expect(json).to include(
           'id' => internal.id,
-          'name' => 'internal_collision')
+          'name' => 'internal_collision',
-      expect(json.fetch('category')).not_to eq('nico')
+          'category' => internal.category)
     end
   end
 

frontend/src/components/common/PageTitle.tsx

@@ -1,10 +1,8 @@
-import React from 'react'
-
 import { cn } from '@/lib/utils'
 
-import type { FC } from 'react'
+import type { ComponentProps, FC } from 'react'
 
-type Props = { children: React.ReactNode; className?: string }
+type Props = ComponentProps<'h1'>
 
 
 const PageTitle: FC<Props> = ({ children, className, ...rest }) => (

frontend/src/lib/queryKeys.ts

@@ -30,6 +30,7 @@ export const tagsKeys = {
     index:        (p: FetchTagsParams) => ['tags', 'index', p] as const,
     nicoRoot:     ['tags', 'nico'] as const,
     nicoIndex:    (p: FetchNicoTagsParams) => ['tags', 'nico', 'index', p] as const,
+    externalShow: (id: string) => ['tags', 'nico', id] as const,
     show:         (name: string) => ['tags', name] as const,
     changes:      (p: { id?: string; page: number; limit: number }) =>
 		      ['tags', 'changes', p] as const,

frontend/src/lib/tags.ts

@@ -53,6 +53,18 @@ export const fetchTag = async (id: string): Promise<Tag | null> => {
 }
 
 
+export const fetchExternalTag = async (id: string): Promise<Tag | null> => {
+  try
+  {
+    return await apiGet (`/tags/nico/${ id }`)
+  }
+  catch
+  {
+    return null
+  }
+}
+
+
 export const fetchTagByName = async (name: string): Promise<Tag | null> => {
   try
   {

frontend/src/pages/posts/PostHistoryPage.test.tsx

@@ -1,7 +1,8 @@
-import { waitFor } from '@testing-library/react'
+import { screen, waitFor } from '@testing-library/react'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 import PostHistoryPage from '@/pages/posts/PostHistoryPage'
+import { buildTag } from '@/test/factories'
 import { renderWithProviders } from '@/test/render'
 
 const postsApi = vi.hoisted (() => ({
@@ -10,7 +11,8 @@ const postsApi = vi.hoisted (() => ({
 }))
 
 const tagsApi = vi.hoisted (() => ({
-  fetchTag: vi.fn (),
+  fetchTag:         vi.fn (),
+  fetchExternalTag: vi.fn (),
 }))
 
 vi.mock ('@/lib/posts', () => postsApi)
@@ -19,13 +21,22 @@ vi.mock ('@/lib/tags', () => tagsApi)
 describe ('PostHistoryPage', () => {
   beforeEach (() => {
     vi.clearAllMocks ()
+
     postsApi.fetchPostChanges.mockResolvedValue ({
       versions: [],
       count:    0,
     })
   })
 
-  it ('filters by external_tag without resolving the id as an internal tag', async () => {
+  it ('shows the external tag name when filtering by external_tag', async () => {
+    const external = buildTag ({
+      id:       7,
+      name:     'nico:external_history',
+      category: 'nico',
+    })
+
+    tagsApi.fetchExternalTag.mockResolvedValue (external)
+
     renderWithProviders (
         <PostHistoryPage/>,
         { route: '/posts/changes?external_tag=7' },
@@ -39,6 +50,14 @@ describe ('PostHistoryPage', () => {
       })
     })
 
+    expect (tagsApi.fetchExternalTag).toHaveBeenCalledWith ('7')
     expect (tagsApi.fetchTag).not.toHaveBeenCalled ()
+
+    expect (
+        await screen.findByRole ('heading', {
+          level: 1,
+          name:  '耕作履歴（nico:external_history）',
+        }),
+    ).toBeInTheDocument ()
   })
 })

frontend/src/pages/posts/PostHistoryPage.tsx

@@ -16,7 +16,7 @@ import { clientAnimationTransition,
 	 clientScrollBehaviour } from '@/lib/clientAnimation'
 import { fetchPostChanges, updatePost } from '@/lib/posts'
 import { postsKeys, tagsKeys } from '@/lib/queryKeys'
-import { fetchTag } from '@/lib/tags'
+import { fetchExternalTag, fetchTag } from '@/lib/tags'
 import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { cn, dateString, originalCreatedAtString } from '@/lib/utils'
 
@@ -64,6 +64,12 @@ const PostHistoryPage: FC = () => {
       queryKey: tagsKeys.show (tagQueryId),
       queryFn:  () => fetchTag (tagQueryId) })
 
+  const externalTagQueryId = externalTagId ?? ''
+  const { data: externalTag } = useQuery ({
+      enabled:  Boolean (externalTagId),
+      queryKey: tagsKeys.externalShow (externalTagQueryId),
+      queryFn:  () => fetchExternalTag (externalTagQueryId) })
+
   const { data, isLoading: loading } = useQuery ({
       queryKey: postsKeys.changes ({ ...(id && { post: id }),
 				     ...(tagId && { tag: tagId }),
@@ -76,6 +82,9 @@ const PostHistoryPage: FC = () => {
 					  page, limit }) })
   const changes = data?.versions ?? []
   const totalPages = data ? Math.ceil (data.count / limit) : 0
+  const displayedTag = externalTag ?? tag
+  const pageTitleLabel = `耕作履歴${ id ? `: 投稿 #${ id }` : '' }${
+      displayedTag ? `（${ displayedTag.name }）` : '' }`
 
   const qc = useQueryClient ()
 
@@ -138,10 +147,14 @@ const PostHistoryPage: FC = () => {
 	  <title>{`耕作履歴 | ${ SITE_TITLE }`}</title>
 	</Helmet>
 
-	<PageTitle>
+	<PageTitle aria-label={pageTitleLabel}>
 	  耕作履歴
 	  {id && <>: 投稿 {<PrefetchLink to={`/posts/${ id }`}>#{id}</PrefetchLink>}</>}
-	  {tag && <>（<TagLink tag={tag} withWiki={false} withCount={false}/>）</>}
+	  {displayedTag && (
+	      <>（<TagLink
+		  tag={displayedTag}
+		  withWiki={false}
+		  withCount={false}/>）</>)}
 	</PageTitle>
 
 	{loading ? 'Loading...' : (