Fix read-article handling across feed filter switches in article view

Article view marks the displayed article read in place (feed.read =
true) without removing it, so currentIndex stays valid while paging.
leaveArticleView() already dropped those afterward, but switching the
feed filter while still in article view never did — so an
already-read article could resurface (re-selecting its feed
re-projected it from allItems as if still unread). Extracted the drop
into a shared dropReadArticles() and call it from setFeedFilter() too.

Also, switching the filter while in article view immediately displays
the new feed's article in full, which is a genuine view — same as
paging or toggling into article view — but nothing marked it read, so
a single-article feed could never be marked read that way at all. This
was deliberately excluded (see commit 169c294) after a generic watch
proved too broad; setFeedFilter() now marks it explicitly, scoped to
article view only, so list view's scroll-driven read-marking is
unaffected.

vue/src/composables/__tests__/useFeeds.spec.js

@@ -12,7 +12,7 @@ class FakeIntersectionObserver {
 vi.stubGlobal('IntersectionObserver', FakeIntersectionObserver)
 
 describe('useFeeds', () => {
-  const { feeds, allItems, feedFilter, feedTitles, feedUnreadCounts, unreadCount, displayedFeedUnreadCounts, refreshUnreadDisplay, setFeedFilter, showMessage, message, showModal, fetchData, sync, getReadable, setInitialLoad, handleIntersection, markAllRead, markRead, setupIntersectionObserver } = useFeeds()
+  const { feeds, allItems, feedFilter, feedTitles, feedUnreadCounts, unreadCount, displayedFeedUnreadCounts, refreshUnreadDisplay, setFeedFilter, showMessage, message, viewMode, fetchData, sync, getReadable, setInitialLoad, handleIntersection, markAllRead, markRead, markCurrentArticleRead, setupIntersectionObserver } = useFeeds()
 
   beforeEach(() => {
     localStorage.setItem('user-token', 'test-token')
@@ -24,7 +24,7 @@ describe('useFeeds', () => {
     feedFilter.value = null
     showMessage.value = false
     message.value = ''
-    showModal.value = false
+    viewMode.value = 'list'
   })
 
   it('fetches and flattens articles for the current user', async () => {
@@ -423,6 +423,60 @@ describe('useFeeds', () => {
       expect(feeds.value.map(f => f.id)).toEqual([2, 1])
     })
 
+    it('does not resurrect an article-view read-in-place article when re-selecting its feed', async () => {
+      axios.get.mockResolvedValueOnce(twoFeedsResponse)
+      axios.put.mockResolvedValue({ status: 200 })
+      await fetchData()
+
+      await setFeedFilter('Feed B')
+      expect(feeds.value.map(f => f.id)).toEqual([2])
+
+      // Article view marks the displayed article read in place (feed.read =
+      // true) without removing it, so currentIndex stays valid while paging —
+      // see markCurrentArticleRead. It's still in the list at this point.
+      markCurrentArticleRead()
+      expect(feeds.value.map(f => f.id)).toEqual([2])
+
+      // Switching to another feed and back must not resurrect it as if it
+      // were still unread.
+      await setFeedFilter('Feed A')
+      await setFeedFilter('Feed B')
+
+      expect(feeds.value).toEqual([])
+    })
+
+    it('marks the newly displayed article read when the filter is switched while in article view', async () => {
+      axios.get.mockResolvedValueOnce(twoFeedsResponse)
+      axios.put.mockResolvedValue({ status: 200 })
+      await fetchData()
+      viewMode.value = 'article'
+
+      // Switching into Feed B while in article view immediately displays its
+      // one article's full content — that counts as "viewed", so it's marked
+      // read the same way toggleViewMode()/nextArticle()/prevArticle() do.
+      await setFeedFilter('Feed B')
+
+      expect(axios.put).toHaveBeenCalledWith('/api/v1/article/read/2', null, expect.anything())
+      expect(feeds.value[0].read).toBe(true)
+
+      // It doesn't resurface either, once dropped on the next switch.
+      await setFeedFilter('Feed A')
+      await setFeedFilter('Feed B')
+      expect(feeds.value).toEqual([])
+    })
+
+    it('does not mark the newly displayed article read when the filter is switched in list view', async () => {
+      axios.get.mockResolvedValueOnce(twoFeedsResponse)
+      await fetchData()
+
+      // List view only shows titles — switching filters there must not mark
+      // anything read; that's still driven solely by scroll (handleIntersection).
+      await setFeedFilter('Feed B')
+
+      expect(axios.put).not.toHaveBeenCalled()
+      expect(feeds.value[0].read).toBeUndefined()
+    })
+
     it('keeps an emptied filtered feed selected and selectable, showing "All caught up"', async () => {
       axios.get.mockResolvedValueOnce(twoFeedsResponse)
       axios.put.mockResolvedValue({ status: 200 })

vue/src/composables/useFeeds.js

@@ -59,7 +59,6 @@ function refreshUnreadDisplay() {
   displayedFeedUnreadCounts.value = feedUnreadCounts.value
 }
 const message = ref('')
-const showModal = ref(false)
 const viewMode = ref(localStorage.getItem('viewMode') || 'list') // 'list' | 'article' — toggled from the hamburger menu, persisted per device
 const currentIndex = ref(0)
 const layout = ref(localStorage.getItem('layout') || 'list') // 'list' | 'cards' — list-view display style, toggled from the hamburger menu
@@ -308,6 +307,22 @@ function applyFilter() {
     : allItems.value.slice()
 }
 
+// Article view marks an article read in place (feed.read = true) without
+// removing it — see markCurrentArticleRead — so currentIndex stays valid while
+// paging within that same list. Anything switches the list out from under
+// that index (leaving article view, or re-filtering while still in it) has to
+// drop those read-in-place articles from the master here, or they resurface:
+// re-selecting their feed would otherwise re-project them from allItems as if
+// still unread.
+function dropReadArticles() {
+  // The feeds.value filter here is redundant for the setFeedFilter() caller
+  // (applyFilter() overwrites feeds.value again right after) but is what
+  // leaveArticleView() actually needs — kept shared rather than split into two
+  // near-identical branches.
+  feeds.value = feeds.value.filter(feed => !feed.read)
+  allItems.value = allItems.value.filter(feed => !feed.read)
+}
+
 // Changes the active feed filter and re-projects. Mirrors toggleLayout's
 // observer/scroll-safe pattern: disconnect first, scroll to top, then re-point
 // the observer at the new .observe nodes after Vue has re-rendered. Works in
@@ -316,9 +331,16 @@ function applyFilter() {
 async function setFeedFilter(title) {
   disconnectObserver()
   window.scrollTo(0, 0)
+  dropReadArticles()
   feedFilter.value = title // null for "All feeds"
   currentIndex.value = 0
   applyFilter()
+  // In article view the item at currentIndex is fully displayed, not just
+  // listed — unlike a plain currentIndex reset from paging, this one really is
+  // "shown" to the user, so mark it the same way toggleViewMode()/nextArticle()/
+  // prevArticle() do. List view only shows titles here; its own read-marking
+  // happens via scroll (handleIntersection), so this must not fire there.
+  if (viewMode.value === 'article') markCurrentArticleRead()
   refreshUnreadDisplay()
   await nextTick()
   setupIntersectionObserver()
@@ -515,9 +537,7 @@ async function leaveArticleView() {
   // Articles paged past in article view were marked read but deliberately kept
   // in place so currentIndex stayed valid — drop them now so they don't keep
   // showing up in the list view.
-  feeds.value = feeds.value.filter(feed => !feed.read)
-  // Shared references — the paged-past objects carry .read on the master too.
-  allItems.value = allItems.value.filter(feed => !feed.read)
+  dropReadArticles()
   currentIndex.value = 0
   viewMode.value = 'list'
   localStorage.setItem('viewMode', viewMode.value)
@@ -588,7 +608,6 @@ export function useFeeds() {
     setFeedFilter,
     showMessage,
     message,
-    showModal,
     viewMode,
     currentIndex,
     toggleViewMode,