#385

frontend/src/components/MaterialSidebar.tsx

@@ -488,25 +488,23 @@ const MaterialSidebar: FC = () => {
 	  </div>
 	</div>
 
-	<div className="hidden md:block">
-	  <SidebarComponent sidebarKey="materials">
-	    <div className="space-y-4">
-	      <MaterialFilterButtons
-		  materialFilter={materialFilter}
-		  onChange={handleFilterChange}/>
-	      {isLoading && (
-		  <p className="text-sm text-neutral-500 dark:text-stone-400">読込中……</p>)}
-	      {isError && (
-		  <p className="text-sm text-red-600 dark:text-red-300">
-		    タグ一覧の取得に失敗しました．
-		  </p>)}
-	      {(!isLoading && !isError) && (
-		  <ul>
-		    {renderDesktopTree (visibleRootTags)}
-		  </ul>)}
-	    </div>
-	  </SidebarComponent>
-	</div>
+	<SidebarComponent sidebarKey="materials" className="hidden md:block">
+	  <div className="space-y-4">
+	    <MaterialFilterButtons
+		materialFilter={materialFilter}
+		onChange={handleFilterChange}/>
+	    {isLoading && (
+		<p className="text-sm text-neutral-500 dark:text-stone-400">読込中……</p>)}
+	    {isError && (
+		<p className="text-sm text-red-600 dark:text-red-300">
+		  タグ一覧の取得に失敗しました．
+		</p>)}
+	    {(!isLoading && !isError) && (
+		<ul>
+		  {renderDesktopTree (visibleRootTags)}
+		</ul>)}
+	  </div>
+	</SidebarComponent>
       </>)
 }
 

frontend/src/components/TagDetailSidebar.tsx

@@ -146,10 +146,13 @@ const DropSlot = ({ cat }: { cat: Category }) => {
 }
 
 
-type Props = { post: Post; sp?: boolean }
+type Props = {
+    className?: string
+    post:       Post
+    sp?:        boolean }
 
 
-const TagDetailSidebar: FC<Props> = ({ post, sp }) => {
+const TagDetailSidebar: FC<Props> = ({ className, post, sp }) => {
   sp = Boolean (sp)
 
   const qc = useQueryClient ()
@@ -278,7 +281,7 @@ const TagDetailSidebar: FC<Props> = ({ post, sp }) => {
   }, [baseTags])
 
   return (
-      <SidebarComponent sidebarKey="post-detail-tags">
+      <SidebarComponent sidebarKey="post-detail-tags" className={className}>
 	<TagSearch/>
 	<DndContext
 	    sensors={sensors}

frontend/src/components/layout/SidebarComponent.test.tsx

@@ -0,0 +1,124 @@
+import { fireEvent, render, screen, waitFor } from '@testing-library/react'
+import { HelmetProvider } from 'react-helmet-async'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+import SidebarComponent from '@/components/layout/SidebarComponent'
+
+
+const sidebarWidth = (element: Element | null): string =>
+    (element as HTMLElement).style.getPropertyValue ('--sidebar-width')
+
+
+const sidebarRoot = (container: HTMLElement): Element =>
+    container.querySelector ('[style*="--sidebar-width"]')!
+
+
+const sidebarTree = (props: Partial<Parameters<typeof SidebarComponent>[0]>) => (
+    <HelmetProvider>
+      <div data-sidebar-container>
+	<SidebarComponent sidebarKey="test-sidebar" {...props}>
+	  Sidebar body
+	</SidebarComponent>
+      </div>
+    </HelmetProvider>)
+
+
+const renderSidebar = (
+    props: Partial<Parameters<typeof SidebarComponent>[0]> = {},
+    containerWidth = 800,
+) => {
+  Object.defineProperty (HTMLElement.prototype, 'clientWidth', {
+      configurable: true,
+      get () {
+	return this.hasAttribute ('data-sidebar-container') ? containerWidth : 0
+      },
+  })
+
+  const rendered = render (sidebarTree (props))
+
+  return rendered
+}
+
+
+describe ('SidebarComponent', () => {
+  beforeEach (() => {
+    Object.defineProperty (window, 'innerWidth', {
+	configurable: true,
+	value:        1_000,
+    })
+
+    Object.defineProperty (HTMLElement.prototype, 'setPointerCapture', {
+	configurable: true,
+	value:        vi.fn (),
+    })
+    Object.defineProperty (HTMLElement.prototype, 'releasePointerCapture', {
+	configurable: true,
+	value:        vi.fn (),
+    })
+    Object.defineProperty (HTMLElement.prototype, 'hasPointerCapture', {
+	configurable: true,
+	value:        vi.fn (() => true),
+    })
+
+    vi.spyOn (HTMLElement.prototype, 'setPointerCapture').mockImplementation (() => {
+      ;
+    })
+    vi.spyOn (HTMLElement.prototype, 'releasePointerCapture').mockImplementation (() => {
+      ;
+    })
+    vi.spyOn (HTMLElement.prototype, 'hasPointerCapture').mockReturnValue (true)
+  })
+
+  it ('uses maxWidth without applying the container main-width reserve twice', async () => {
+    localStorage.setItem ('sidebar:test-sidebar:left:width', '700')
+    const onWidthChange = vi.fn ()
+
+    const { container } = renderSidebar ({ maxWidth: 700, onWidthChange }, 800)
+
+    await waitFor (() => {
+      expect (sidebarWidth (sidebarRoot (container))).toBe ('700px')
+    })
+    expect (onWidthChange).toHaveBeenLastCalledWith (700)
+  })
+
+  it ('resets width and removes only its storage key on double click', async () => {
+    localStorage.setItem ('sidebar:test-sidebar:right:width', '420')
+    localStorage.setItem ('sidebar:other-sidebar:right:width', '480')
+
+    const { container } = renderSidebar ({ side: 'right' }, 900)
+
+    await waitFor (() => {
+      expect (sidebarWidth (sidebarRoot (container))).toBe ('420px')
+    })
+
+    fireEvent.doubleClick (screen.getByRole ('separator', { name: 'サイドバー幅' }))
+
+    await waitFor (() => {
+      expect (sidebarWidth (sidebarRoot (container))).toBe ('256px')
+    })
+    expect (localStorage.getItem ('sidebar:test-sidebar:right:width')).toBeNull ()
+    expect (localStorage.getItem ('sidebar:other-sidebar:right:width')).toBe ('480')
+  })
+
+  it ('clamps current width on maxWidth changes without re-reading storage', async () => {
+    localStorage.setItem ('sidebar:test-sidebar:left:width', '420')
+
+    const { container, rerender } = renderSidebar ({ maxWidth: 420 }, 900)
+
+    await waitFor (() => {
+      expect (sidebarWidth (sidebarRoot (container))).toBe ('420px')
+    })
+
+    rerender (sidebarTree ({ maxWidth: 300 }))
+
+    await waitFor (() => {
+      expect (sidebarWidth (sidebarRoot (container))).toBe ('300px')
+    })
+
+    rerender (sidebarTree ({ maxWidth: 500 }))
+
+    await waitFor (() => {
+      expect (sidebarWidth (sidebarRoot (container))).toBe ('300px')
+    })
+  })
+})

frontend/src/components/layout/SidebarComponent.tsx

@@ -47,23 +47,16 @@ const getSidebarMaxWidth = (containerWidth: number): number => {
 }
 
 
-const clampSidebarWidth = (width: number, containerWidth: number): number =>
-    Math.min (getSidebarMaxWidth (containerWidth), Math.max (MIN_SIDEBAR_WIDTH, width))
-
-
 const readStoredSidebarWidth = (
     sidebarKey: string,
-    side: SidebarSide,
-    containerWidth: number): number => {
+    side: SidebarSide): number => {
   if (typeof window === 'undefined')
     return DEFAULT_SIDEBAR_WIDTH
 
   const value = window.localStorage.getItem (storageKeyForSidebar (sidebarKey, side))
   const width = value == null ? Number.NaN : Number (value)
 
-  return Number.isFinite (width)
-	 ? clampSidebarWidth (width, containerWidth)
-	 : clampSidebarWidth (DEFAULT_SIDEBAR_WIDTH, containerWidth)
+  return Number.isFinite (width) ? width : DEFAULT_SIDEBAR_WIDTH
 }
 
 
@@ -76,6 +69,7 @@ const SidebarComponent: FC<Props> = ({
     side = 'left',
 }) => {
   const rootRef = useRef<HTMLDivElement | null> (null)
+  const maxWidthRef = useRef (maxWidth)
   const getContainerWidth = useCallback (() => {
     const containerWidth = rootRef.current
 	?.closest ('[data-sidebar-container]')
@@ -90,18 +84,20 @@ const SidebarComponent: FC<Props> = ({
 	typeof window === 'undefined' ? containerWidth : window.innerWidth
     const viewportMaxWidth = Math.floor (viewportWidth * MAX_VIEWPORT_WIDTH_RATIO)
     const maxAllowedWidth =
-	maxWidth == null
+	maxWidthRef.current == null
 	? getSidebarMaxWidth (containerWidth)
-	: Math.max (MIN_SIDEBAR_WIDTH, Math.min (viewportMaxWidth, maxWidth))
+	: Math.max (
+	    MIN_SIDEBAR_WIDTH,
+	    Math.min (viewportMaxWidth, maxWidthRef.current))
 
     return Math.min (maxAllowedWidth, Math.max (MIN_SIDEBAR_WIDTH, nextWidth))
-  }, [maxWidth])
+  }, [])
 
   const [width, setWidth] = useState (() => (
       typeof window === 'undefined'
       ? DEFAULT_SIDEBAR_WIDTH
       : getClampedWidth (
-	  readStoredSidebarWidth (sidebarKey, side, window.innerWidth),
+	  readStoredSidebarWidth (sidebarKey, side),
 	  window.innerWidth)))
   const [resizing, setResizing] = useState (false)
   const widthRef = useRef (width)
@@ -160,6 +156,21 @@ const SidebarComponent: FC<Props> = ({
     restoreBodyStyle ()
   }, [clearLongPressTimer, restoreBodyStyle, sidebarKey])
 
+  const applyWidth = useCallback ((nextWidth: number) => {
+    if (nextWidth === widthRef.current)
+      return
+
+    widthRef.current = nextWidth
+    setWidth (nextWidth)
+  }, [])
+
+  useEffect (() => {
+    maxWidthRef.current = maxWidth
+    const containerWidth = getContainerWidth ()
+    const nextWidth = getClampedWidth (widthRef.current, containerWidth)
+    applyWidth (nextWidth)
+  }, [applyWidth, getClampedWidth, getContainerWidth, maxWidth])
+
   const updateWidth = useCallback ((clientX: number) => {
     const state = resizeRef.current
     if (state == null)
@@ -170,9 +181,8 @@ const SidebarComponent: FC<Props> = ({
 		  ? clientX - state.startX
 		  : state.startX - clientX
     const nextWidth = getClampedWidth (state.startWidth + delta, containerWidth)
-    widthRef.current = nextWidth
-    setWidth (nextWidth)
-  }, [getClampedWidth, getContainerWidth])
+    applyWidth (nextWidth)
+  }, [applyWidth, getClampedWidth, getContainerWidth])
 
   const handlePointerDown = (ev: PointerEvent<HTMLDivElement>) => {
     if (ev.pointerType !== 'mouse' && ev.pointerType !== 'touch')
@@ -242,10 +252,9 @@ const SidebarComponent: FC<Props> = ({
   const resetWidth = useCallback (() => {
     const containerWidth = getContainerWidth ()
     const nextWidth = getClampedWidth (DEFAULT_SIDEBAR_WIDTH, containerWidth)
-    widthRef.current = nextWidth
-    setWidth (nextWidth)
+    applyWidth (nextWidth)
     window.localStorage.removeItem (storageKeyForSidebar (sidebarKey, side))
-  }, [getClampedWidth, getContainerWidth, sidebarKey, side])
+  }, [applyWidth, getClampedWidth, getContainerWidth, sidebarKey, side])
 
   const handleDoubleClick = (ev: MouseEvent<HTMLDivElement>) => {
     ev.preventDefault ()
@@ -256,11 +265,16 @@ const SidebarComponent: FC<Props> = ({
   useEffect (() => {
     const containerWidth = getContainerWidth ()
     const nextWidth = getClampedWidth (
-	readStoredSidebarWidth (sidebarKey, side, containerWidth),
+	readStoredSidebarWidth (sidebarKey, side),
 	containerWidth)
-    widthRef.current = nextWidth
-    setWidth (nextWidth)
-  }, [getClampedWidth, getContainerWidth, sidebarKey, side])
+    applyWidth (nextWidth)
+  }, [applyWidth, getClampedWidth, getContainerWidth, sidebarKey, side])
+
+  useEffect (() => {
+    const containerWidth = getContainerWidth ()
+    const nextWidth = getClampedWidth (widthRef.current, containerWidth)
+    applyWidth (nextWidth)
+  }, [applyWidth, getClampedWidth, getContainerWidth])
 
   useEffect (() => {
     if (typeof window === 'undefined')
@@ -269,16 +283,12 @@ const SidebarComponent: FC<Props> = ({
     const handleResize = () => {
       const containerWidth = getContainerWidth ()
       const nextWidth = getClampedWidth (widthRef.current, containerWidth)
-      if (nextWidth === widthRef.current)
-	return
-
-      widthRef.current = nextWidth
-      setWidth (nextWidth)
+      applyWidth (nextWidth)
     }
 
     window.addEventListener ('resize', handleResize)
     return () => window.removeEventListener ('resize', handleResize)
-  }, [getClampedWidth, getContainerWidth])
+  }, [applyWidth, getClampedWidth, getContainerWidth])
 
   useEffect (() => {
     onWidthChange?.(width)

frontend/src/pages/materials/MaterialBasePage.tsx

@@ -6,7 +6,9 @@ import type { FC } from 'react'
 
 
 const MaterialBasePage: FC = () => (
-    <div className="md:flex md:flex-1 overflow-y-auto md:overflow-y-hidden">
+    <div
+	data-sidebar-container
+	className="md:flex md:flex-1 overflow-y-auto md:overflow-y-hidden">
       <MaterialSidebar/>
       <Outlet/>
     </div>)

frontend/src/pages/posts/PostDetailPage.tsx

@@ -92,16 +92,16 @@ const PostDetailPage: FC<Props> = ({ user }) => {
 		       : 'bg-gray-500 hover:bg-gray-600')
 
   return (
-      <div className="md:flex md:flex-1 overflow-y-auto md:overflow-y-hidden">
+      <div
+	  data-sidebar-container
+	  className="md:flex md:flex-1 overflow-y-auto md:overflow-y-hidden">
 	<Helmet>
 	  {(post?.thumbnail || post?.thumbnailBase) && (
 	      <meta name="thumbnail" content={post.thumbnail! || post.thumbnailBase!}/>)}
 	  {post && <title>{`${ post.title || post.url } | ${ SITE_TITLE }`}</title>}
 	</Helmet>
 
-	<div className="hidden md:block">
-	  {post && <TagDetailSidebar post={post}/>}
-	</div>
+	{post && <TagDetailSidebar post={post} className="hidden md:block"/>}
 
 	<MainArea className="relative">
 	  {post
@@ -179,9 +179,7 @@ const PostDetailPage: FC<Props> = ({ user }) => {
 	   : 'Loading...'}
 	</MainArea>
 
-	<div className="md:hidden">
-	  {post && <TagDetailSidebar post={post} sp/>}
-	</div>
+	{post && <TagDetailSidebar post={post} sp className="md:hidden"/>}
       </div>)
 }
 

frontend/src/pages/posts/PostListPage.tsx

@@ -70,6 +70,7 @@ const PostListPage: FC = () => {
 
   return (
       <div
+	  data-sidebar-container
 	  className="md:flex md:flex-1 overflow-y-auto md:overflow-y-hidden"
 	  ref={containerRef}>
 	<Helmet>

frontend/src/pages/theatres/TheatreDetailPage.test.tsx

@@ -105,6 +105,20 @@ const tagSection = (): HTMLElement =>
   screen.getAllByRole ('heading', { name: 'タグ' })[0].closest ('section')!
 
 const mockDefaultApi = () => {
+  let commentsFetched = false
+  let currentTheatreInfo = buildTheatreInfo ({
+    postId:        currentPost.id,
+    postStartedAt: '2026-01-02T03:04:05.000Z',
+    postElapsedMs: 1_000,
+    watchingUsers,
+    skipVote:      {
+      votesCount:         0,
+      requiredCount:      2,
+      watchingUsersCount: watchingUsers.length,
+      voted:              false,
+    },
+  })
+
   api.apiGet.mockImplementation ((path: string) => {
     switch (path)
     {
@@ -112,13 +126,17 @@ const mockDefaultApi = () => {
       return Promise.resolve (theatre)
 
     case '/theatres/7/comments':
+      if (commentsFetched)
+	return Promise.resolve ([])
+
+      commentsFetched = true
       return Promise.resolve ([
-        buildTheatreComment ({
-          theatreId: 7,
-          no:        2,
-          user:      { id: 1, name: 'tester' },
-          content:   '視聴コメント',
-        }),
+	  buildTheatreComment ({
+	    theatreId: 7,
+	    no:        2,
+	    user:      { id: 1, name: 'tester' },
+	    content:   '視聴コメント',
+	  }),
       ])
 
     case '/theatres/7/programmes':
@@ -136,32 +154,22 @@ const mockDefaultApi = () => {
     switch (path)
     {
     case '/theatres/7/watching':
-      return Promise.resolve (buildTheatreInfo ({
-        postId:        currentPost.id,
-        postStartedAt: '2026-01-02T03:04:05.000Z',
-        postElapsedMs: 1_000,
-        watchingUsers,
-        skipVote:      {
-          votesCount:         0,
-          requiredCount:      2,
-          watchingUsersCount: watchingUsers.length,
-          voted:              false,
-        },
-      }))
+      return Promise.resolve (currentTheatreInfo)
 
     case '/theatres/7/skip_vote':
-      return Promise.resolve (buildTheatreInfo ({
-        postId:        currentPost.id,
-        postStartedAt: '2026-01-02T03:04:05.000Z',
-        postElapsedMs: 2_000,
-        watchingUsers,
-        skipVote:      {
-          votesCount:         1,
-          requiredCount:      2,
-          watchingUsersCount: watchingUsers.length,
-          voted:              true,
-        },
-      }))
+      currentTheatreInfo = buildTheatreInfo ({
+	postId:        currentPost.id,
+	postStartedAt: '2026-01-02T03:04:05.000Z',
+	postElapsedMs: 2_000,
+	watchingUsers,
+	skipVote:      {
+	  votesCount:         1,
+	  requiredCount:      2,
+	  watchingUsersCount: watchingUsers.length,
+	  voted:              true,
+	},
+      })
+      return Promise.resolve (currentTheatreInfo)
 
     default:
       return Promise.reject (new Error (`Unexpected PUT ${ path }`))

frontend/src/pages/theatres/TheatreDetailPage.tsx

@@ -266,6 +266,7 @@ const TheatreDetailPage: FC<Props> = ({ user }: Props) => {
 
   const applyTheatreInfo = useCallback ((nextInfo: TheatreInfo) => {
     theatreInfoReceivedAtRef.current = performance.now ()
+    theatreInfoRef.current = nextInfo
     setTheatreInfo (nextInfo)
   }, [])
 
@@ -406,6 +407,9 @@ const TheatreDetailPage: FC<Props> = ({ user }: Props) => {
 	    setComments (prev => [...newComments, ...prev])
 	  }
 
+	if (loadingRef.current)
+	  return
+
 	const currentInfo = theatreInfoRef.current
 	const ended =
 	    currentInfo.hostFlg
@@ -427,8 +431,9 @@ const TheatreDetailPage: FC<Props> = ({ user }: Props) => {
 	    return
 	  }
 
+	const watchingRequestedAt = performance.now ()
 	const nextInfo = await apiPut<TheatreInfo> (`/theatres/${ id }/watching`)
-	if (!(cancelled))
+	if (!(cancelled) && watchingRequestedAt >= theatreInfoReceivedAtRef.current)
 	  applyTheatreInfo (nextInfo)
       }
       catch (error)
@@ -557,6 +562,7 @@ const TheatreDetailPage: FC<Props> = ({ user }: Props) => {
     if (!(id) || !(post))
       return
 
+    loadingRef.current = true
     setLoading (true)
     try
     {
@@ -585,6 +591,7 @@ const TheatreDetailPage: FC<Props> = ({ user }: Props) => {
     }
     finally
     {
+      loadingRef.current = false
       setLoading (false)
     }
   }