web/src/home/UpdatesSheet.test.tsx

@@ -84,6 +84,12 @@ function homeReads(fetchMock: Mock<typeof fetch>) {
     .length
 }
 
+function updatesReads(fetchMock: Mock<typeof fetch>) {
+  return fetchMock.mock.calls.filter(
+    ([input, init]) => String(input) === UPDATES_PATH && (init?.method ?? 'GET') === 'GET',
+  ).length
+}
+
 // Where shows the route a row went to.
 function Where() {
   const location = useLocation()
@@ -201,6 +207,56 @@ describe('Recent updates sheet', () => {
     expect(screen.queryByTestId('unread-dot')).not.toBeInTheDocument()
   })
 
+  it('on an immediate reopen waits for that opening’s read, and marks the newer event seen, not the list held from before', async () => {
+    const stored = [...UPDATES.updates]
+    let reads = 0
+    let answer: (() => void) | undefined
+    const fetchMock = stubServer({
+      [`GET ${UPDATES_PATH}`]: () => {
+        const body = { updates: [...stored] }
+        reads++
+        // Every reading after the first is held until the test answers it.
+        if (reads === 1) return jsonResponse(200, body)
+        return new Promise<Response>((resolve) => (answer = () => resolve(jsonResponse(200, body))))
+      },
+    })
+    await renderHome()
+    await rows(await openSheet())
+    await waitFor(() => expect(posts(fetchMock)).toHaveLength(1))
+
+    // Closed and opened again at once, before any cache-collection timer
+    // could run, with a new event stored in between.
+    fireEvent.keyDown(screen.getByRole('dialog'), { key: 'Escape' })
+    const reminder = {
+      type: 'day_of_reminder',
+      title: 'Tacos tonight',
+      body: 'Dinner at 6:00.',
+      url: '/plan',
+      created_at: new Date().toISOString(),
+    }
+    stored.unshift(reminder)
+    fireEvent.click(screen.getByRole('button', { name: /^Recent updates/ }))
+    const sheet = screen.getByRole('dialog', { name: 'Recent updates' })
+
+    // The list held from the first opening is neither shown nor marked
+    // seen while this opening's read is in flight.
+    await waitFor(() => expect(updatesReads(fetchMock)).toBe(2))
+    expect(within(sheet).getByLabelText('Updates loading')).toBeInTheDocument()
+    expect(within(sheet).queryByRole('list')).not.toBeInTheDocument()
+    expect(posts(fetchMock)).toHaveLength(1)
+
+    answer!()
+    const listed = await rows(sheet)
+    expect(listed).toHaveLength(4)
+    expect(listed[0]).toHaveTextContent('Tacos tonight')
+    await waitFor(() =>
+      expect(posts(fetchMock)).toEqual([
+        JSON.stringify({ through: UPDATES.updates[0]!.created_at }),
+        JSON.stringify({ through: reminder.created_at }),
+      ]),
+    )
+  })
+
   it.each([
     [0, '/plan'],
     [1, '/discover'],

web/src/home/UpdatesSheet.tsx

@@ -44,7 +44,10 @@ function Updates({ onOpen }: { onOpen: (url: string) => void }) {
   const updates = useUpdates()
   const markSeen = useMarkUpdatesSeen()
   const { mutate } = markSeen
-  const newest = updates.data?.[0]?.created_at
+  // fresh says this opening's read has come back; until then a list still
+  // held from an earlier opening is neither shown nor marked seen.
+  const fresh = updates.isSuccess && updates.isFetchedAfterMount
+  const newest = fresh ? updates.data[0]?.created_at : undefined
   // The instant the relative times count from, fixed while the sheet is
   // open.
   const [now] = useState(() => new Date())
@@ -58,7 +61,7 @@ function Updates({ onOpen }: { onOpen: (url: string) => void }) {
       <ErrorBanner onRetry={() => void updates.refetch()}>Couldn't load your updates. {updates.error.message}</ErrorBanner>
     )
   }
-  if (updates.isPending) {
+  if (!fresh) {
     return (
       <div aria-busy="true" aria-label="Updates loading" className={styles.rows}>
         {Array.from({ length: 3 }, (_, i) => (

web/src/home/api.ts

@@ -144,16 +144,16 @@ export function parseUpdates(where: string, body: unknown, origin: string): Upda
 }
 
 // useUpdates is the Recent updates (GET /api/v1/updates): the last ten
-// notification events, newest first. The list is dropped as soon as the
-// sheet showing it closes (gcTime 0), so each opening reads it afresh and
-// never shows, or marks seen, a list read before an event stored since.
+// notification events, newest first. Each opening of the sheet reads it
+// afresh (refetchOnMount 'always'), whatever the query client still holds;
+// the sheet shows, and marks seen, only the list that opening read.
 export function useUpdates() {
   const { apiFetch } = useApi()
   return useQuery({
     queryKey: UPDATES_KEY,
     queryFn: async () =>
       parseUpdates(`GET ${UPDATES_PATH}`, await apiFetch<unknown>(UPDATES_PATH), window.location.origin),
-    gcTime: 0,
+    refetchOnMount: 'always',
   })
 }