web/src/screens/LibrariesScreen.test.tsx

@@ -186,6 +186,29 @@ describe('LibrariesScreen', () => {
     expect(handle.fetchSpy).toHaveBeenCalledWith('/api/v1/libraries/scan-status', expect.any(Object));
   });
 
+  it('renders "Never scanned" for a DateTime.MinValue-seeded lastScan, not a bogus midnight time (#409)', async () => {
+    mockApi({
+      mediaSources: [
+        mediaSource({
+          libraries: [
+            library({ id: 31, itemCount: 0, lastScan: '0001-01-01T00:00:00', mediaKind: 'Movies', name: 'Movies' }),
+            library({ id: 32, itemCount: 0, lastScan: null, mediaKind: 'Shows', name: 'TV Shows' })
+          ]
+        })
+      ]
+    });
+
+    render(<LibrariesScreen />);
+
+    expect((await screen.findAllByText('Movies')).length).toBeGreaterThan(0);
+    // Both the never-scanned-MinValue library row and the never-scanned-null library row read
+    // "Never scanned" - a plain `Boolean(lastScan)` truthiness check would treat the MinValue string
+    // as a real scan and print "Last scan 12:00 AM" instead.
+    expect(screen.getAllByText('Never scanned').length).toBeGreaterThanOrEqual(2);
+    expect(screen.queryByText(/Last scan/)).not.toBeInTheDocument();
+    expect(screen.queryByText(/12:00 AM/)).not.toBeInTheDocument();
+  });
+
   it('converts 0 and 1 fractional scan-status percents to 0% and 100%', async () => {
     mockApi({
       libraryScanStatuses: [
@@ -255,8 +278,18 @@ describe('LibrariesScreen', () => {
     const sourceFetchesBeforeCompletion = fetchCount(handle, '/api/v1/media-sources');
     await runPollTick(intervalHandlers);
 
-    expect(screen.queryByText('75%')).not.toBeInTheDocument();
-    expect(fetchCount(handle, '/api/v1/media-sources')).toBe(sourceFetchesBeforeCompletion + 1);
+    // loadScanStatuses (the interval handler) kicks off its own Promise.all(...).then(...) chain
+    // (libraries.ts) rather than being itself async/awaitable, so `handler()` returns void - the
+    // state update that clears the progress bar and the follow-up loadSources() refetch both land a
+    // few microtask ticks after runPollTick's `act(async () => ...)` callback has already resolved.
+    // Asserting synchronously right after the tick races that chain (#447); waitFor lets both
+    // settle before asserting, without weakening either check.
+    await waitFor(() => {
+      expect(screen.queryByText('75%')).not.toBeInTheDocument();
+    });
+    await waitFor(() => {
+      expect(fetchCount(handle, '/api/v1/media-sources')).toBe(sourceFetchesBeforeCompletion + 1);
+    });
   });
 
   it('reconciles a 409 "already scanning" against scan-status without an error toast (#232)', async () => {

web/src/screens/LibrariesScreen.tsx

@@ -394,7 +394,7 @@ function LibraryRow({
       <div className="ctv-library-row-main">
         <strong>{library.name}</strong>
         <span><span>{formatLibraryMediaKind(library.mediaKind)}</span> · <code>{library.itemCount.toLocaleString()}</code> items</span>
-        <small>{library.lastScan ? `Last scan ${formatDateTime(library.lastScan)}` : 'Never scanned'}</small>
+        <small>{hasScanned(library.lastScan) ? `Last scan ${formatDateTime(library.lastScan)}` : 'Never scanned'}</small>
       </div>
       <div className="ctv-library-row-status">
         {scanStatus ? (
@@ -465,12 +465,33 @@ function formatLibraryMediaKind(kind: string): string {
 function sourceLastScanLabel(source: MediaSource): string {
   const scans = source.libraries
     .map((library) => library.lastScan)
-    .filter((scan): scan is string => Boolean(scan))
+    .filter((scan): scan is string => hasScanned(scan))
     .sort();
 
   return scans.length > 0 ? `Last scan ${formatDateTime(scans[scans.length - 1])}` : 'Never scanned';
 }
 
+// A never-scanned local library's LastScan is seeded as DateTime.MinValue (not NULL), which the API
+// serialises as the truthy string "0001-01-01T00:00:00" - a plain `Boolean(scan)` truthiness check
+// (the previous behavior here) treats that as a real scan and renders a bogus midnight time (#409).
+// Detect the MinValue sentinel client-side alongside null/undefined so both render "Never scanned".
+// (Server-side normalisation of the DTO was considered - see #409 - but the SPA already owns every
+// consumer of this field, so a read-boundary fix here covers both call sites without touching the API.)
+function hasScanned(scan: string | null | undefined): scan is string {
+  if (!scan) {
+    return false;
+  }
+
+  const parsed = new Date(scan);
+  if (Number.isNaN(parsed.getTime())) {
+    return false;
+  }
+
+  // DateTime.MinValue is year 0001; treat anything before year 1900 as "no real scan" rather than
+  // matching the exact sentinel string, so any equivalent epoch-ish placeholder is also caught.
+  return parsed.getUTCFullYear() >= 1900;
+}
+
 // Inlined rather than imported back from App.tsx (mirrors the ChannelsScreen #244 extraction):
 // App.tsx's formatDateTime is still used by other App.tsx-owned screens (Playouts, Guide), so
 // keeping this screen self-sufficient means duplicating the tiny formatter here.