Protocol 15: one shared session log on the server, chat never logged, Mark a problem

Every app streams its redacted diagnostic lines (server time, batched
every 10 s, gzip, buffered while offline) to POST /l/; the server merges
them with its own into session-YYYY-MM-DD.log in time order, tagged by
who. Opt-out in Settings > About; Mark a problem (Ctrl+Shift+B, the
player menus, About) writes a marker with an optional note. Copy
diagnostics can include the server's session log. Chat text never
reaches any log.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/desktop/lib/src/controls/player_settings.dart

@@ -8,6 +8,7 @@ import '../jellyfin/track_prefs.dart' show MpvTrack;
 import '../playback/playback_controller.dart' show PlaybackController, RenderMode;
 import '../shaders/shader_presets.dart';
 import '../state/session_state.dart';
+import '../shell/mark_problem.dart';
 import '../shell/motion.dart';
 import '../state/settings.dart';
 import '../widgets/app_menu.dart';
@@ -332,9 +333,16 @@ class PlayerSettingsCard extends StatelessWidget {
                 const TrackSetting(type: JellyfinStreamType.audio),
               ],
               const SizedBox(height: 4),
-              Text(
-                'Custom shader files: Settings → Player',
-                style: TextStyle(color: Theme.of(context).colorScheme.onSurfaceVariant, fontSize: 12),
+              Row(
+                children: [
+                  Expanded(
+                    child: Text(
+                      'Custom shader files: Settings → Player',
+                      style: TextStyle(color: Theme.of(context).colorScheme.onSurfaceVariant, fontSize: 12),
+                    ),
+                  ),
+                  const MarkProblemButton(),
+                ],
               ),
             ],
           ),

apps/desktop/lib/src/platform/app_log.dart

@@ -44,8 +44,10 @@ Future<void> startAppLogging() async {
 }
 
 /// The text "Copy diagnostics" gives: versions, then the last [since] of
-/// the app log (its hosted server's records included), already redacted.
-Future<String> diagnosticsText({Duration since = const Duration(hours: 6)}) async {
+/// the app log (its hosted server's records included), already redacted;
+/// with [sessionLog], the server's session log of the same hours after it
+/// (every member's shared lines and the server's, merged).
+Future<String> diagnosticsText({Duration since = const Duration(hours: 6), bool sessionLog = false}) async {
   final b = StringBuffer()
     ..writeln('$appName ${displayVersion()}')
     ..writeln('OS: ${Platform.operatingSystem} ${Platform.operatingSystemVersion}')
@@ -68,6 +70,13 @@ Future<String> diagnosticsText({Duration since = const Duration(hours: 6)}) asyn
   b.writeln('Log: ${files?.currentPath ?? 'none (console only)'}');
   b.writeln('--- last ${since.inHours} h of the log ---');
   b.write(files?.recent(since) ?? '');
+  if (sessionLog) {
+    final server = await SessionState.instance.coordinator.sessionLog(hours: since.inHours);
+    b
+      ..writeln()
+      ..writeln("--- last ${since.inHours} h of the server's session log ---")
+      ..write(server ?? "(none: the server keeps no session log, or it couldn't be reached)");
+  }
   return redactLog(b.toString());
 }
 

apps/desktop/lib/src/screens/home/about_page.dart

@@ -1,7 +1,12 @@
 import 'package:flutter/material.dart';
+import 'package:signals/signals_flutter.dart';
 
 import '../../platform/app_log.dart';
+import '../../shell/mark_problem.dart';
+import '../../state/session_state.dart';
+import '../../state/settings.dart';
 import '../../update/update_controller.dart';
+import '../../widgets/app_menu.dart';
 import '../../widgets/copy_open.dart';
 import 'settings_page.dart';
 import 'ui.dart';
@@ -45,18 +50,24 @@ class AboutPanel extends StatelessWidget {
               ),
               const SizedBox(height: kGap),
               Text('Something went wrong? Copy diagnostics and send them to whoever helps you: '
-                  'versions and the last hours of the log, passwords, tokens and cookies left out.',
+                  'versions and the last hours of the log, passwords, tokens and cookies left out. '
+                  'In a session it can add the server\'s session log, everyone\'s lines merged. '
+                  'Mark a problem (Ctrl+Shift+B) when it happens so the spot is easy to find.',
                   style: t.bodySmall?.copyWith(color: Colors.grey)),
               const SizedBox(height: 8),
               Wrap(
                 spacing: 8,
                 runSpacing: 8,
                 children: [
-                  FilledButton.tonalIcon(
-                    onPressed: _copyDiagnostics,
-                    icon: const Icon(Icons.bug_report_outlined, size: 18),
-                    label: const Text('Copy diagnostics'),
+                  Builder(
+                    builder: (context) => FilledButton.tonalIcon(
+                      key: const ValueKey('copy-diagnostics'),
+                      onPressed: () => _copyDiagnostics(context),
+                      icon: const Icon(Icons.bug_report_outlined, size: 18),
+                      label: const Text('Copy diagnostics'),
+                    ),
                   ),
+                  const MarkProblemButton(outlined: true),
                   OutlinedButton.icon(
                     onPressed: appLogDir == null ? null : () => _openLogs(),
                     icon: const Icon(Icons.folder_open, size: 18),
@@ -64,13 +75,36 @@ class AboutPanel extends StatelessWidget {
                   ),
                 ],
               ),
+              const SizedBox(height: 8),
+              SignalBuilder(
+                builder: (context) => SwitchListTile(
+                  key: const ValueKey('share-diagnostics'),
+                  contentPadding: EdgeInsets.zero,
+                  title: const Text('Share diagnostics with the server'),
+                  subtitle: const Text('In a session, this app\'s log goes to the server\'s session log, '
+                      'merged with everyone\'s, so a problem can be read afterwards. Never chat; '
+                      'passwords and tokens left out. Off: only a problem you mark is sent.'),
+                  value: AppSettings.instance.shareDiagnostics.value,
+                  onChanged: AppSettings.instance.setShareDiagnostics,
+                ),
+              ),
             ],
           ),
         );
   }
 
-  static Future<void> _copyDiagnostics() async {
-    final text = await diagnosticsText();
+  /// In a session it asks whether to add the server's session log.
+  static Future<void> _copyDiagnostics(BuildContext context) async {
+    var withServer = false;
+    if (SessionState.instance.route.peek() == AppRoute.session) {
+      final pick = await showAppMenu<bool>(context, items: const [
+        AppMenuItem(value: false, label: "This app's log"),
+        AppMenuItem(value: true, label: "This app's and the server's session log"),
+      ]);
+      if (pick == null) return;
+      withServer = pick;
+    }
+    final text = await diagnosticsText(sessionLog: withServer);
     final saved = await saveDiagnostics(text);
     await copyToClipboard(text,
         done: saved == null ? 'Diagnostics copied' : 'Diagnostics copied (also saved in the logs folder)');

apps/desktop/lib/src/screens/home/settings_page.dart

@@ -23,6 +23,7 @@ const sessionShortcuts = [
   ('Ctrl+1…6', 'Shaders: Anime4K mode A, B, C, A+A, B+B, C+A'),
   ('Ctrl+0', 'Shaders off'),
   ('Esc', 'Close the panel or fullscreen, shrink the player, then ask to leave'),
+  ('Ctrl+Shift+B', 'Mark a problem in the session log (anywhere)'),
 ];
 
 /// One titled card of the Settings tab (rounded Material, so list tiles

apps/desktop/lib/src/session/session_coordinator.dart

@@ -17,6 +17,7 @@ import '../playback/playback_controller.dart';
 import '../platform/attention.dart';
 import '../playback/yt_dlp_app.dart';
 import '../schedule/anilist.dart';
+import '../screens/home/ui.dart' show appName, displayVersion;
 import '../screens/home/picked_media.dart';
 import '../sfx/sfx.dart';
 import '../state/settings.dart';
@@ -174,6 +175,32 @@ class SessionCoordinator {
   /// The app's yt-dlp and link probes (tests pass their own).
   final AppYtDlp ytDlp;
   final SyncClient sync = SyncClient();
+  /// This app's log lines to the server's session log (Settings: "Share
+  /// diagnostics with the server"), and "Mark a problem".
+  late final DiagUploader diag = DiagUploader(
+      target: _diagTarget, version: '$appName ${displayVersion()} on ${Platform.operatingSystem}');
+
+  DiagTarget? _diagTarget() {
+    final uri = sync.wsUri;
+    if (sync.token.isEmpty || uri == null || !sync.clockSync.hasSample) return null;
+    return (base: DiagUploader.baseOf(uri), token: sync.token, offsetMs: sync.clockSync.offsetMs);
+  }
+
+  /// "Mark a problem": a marker with [note] in the server's session log
+  /// (and this app's log). False when not in a session: then only this
+  /// app's log has it.
+  Future<bool> markProblem(String note) async {
+    if (!diag.running) {
+      createLogger(DiagUploader.markLogger).warning('=== PROBLEM marked${note.trim().isEmpty ? '' : ': ${note.trim()}'} ===');
+      return false;
+    }
+    await diag.markProblem(note);
+    return true;
+  }
+
+  /// The server's session log of the last [hours], null when not in a
+  /// session or the server has none.
+  Future<String?> sessionLog({int hours = 6}) => diag.fetchSessionLog(hours: hours);
   /// Up next: the server's queue, adding to it, and putting items up.
   late final QueueController queue = QueueController(this);
   /// The server has a password (it fetches links only then).
@@ -498,6 +525,9 @@ class SessionCoordinator {
     }
     markInput();
     _subscribe();
+    diag
+      ..share = AppSettings.instance.shareDiagnostics.peek()
+      ..start();
     feedLog.value = [];
     toasts.value = [];
     await initPlayer();
@@ -1201,6 +1231,9 @@ class SessionCoordinator {
         toasts.peek().where((t) => now.difference(t.at).inSeconds < 4).toList();
     final r = serverState.peek();
     if (sync.token.isNotEmpty) sync.sendPing();
+    diag
+      ..share = AppSettings.instance.shareDiagnostics.peek()
+      ..tick();
     if (sync.token.isNotEmpty && r != null && _playerReady) {
       _sendReport(r);
       if (!_lastOut) {
@@ -2235,6 +2268,8 @@ class SessionCoordinator {
     try {
       await playback.dispose();
     } catch (_) {}
+    // The last lines go before the token does.
+    await diag.stop();
     try {
       await sync.disconnect();
     } catch (_) {}

apps/desktop/lib/src/shell/mark_problem.dart

@@ -0,0 +1,113 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:sync_relay_core/core.dart' show RelayConstants;
+
+import '../state/session_state.dart';
+import '../widgets/app_menu.dart' show AppGlass;
+import 'motion.dart';
+
+// "Mark a problem" (Ctrl+Shift+B, the player's ⚙, Settings → About): a
+// marker line in the server's session log at this moment, with an
+// optional short note, so whoever reads the log finds the spot.
+
+/// The key that opens it.
+const markProblemKey = SingleActivator(LogicalKeyboardKey.keyB, control: true, shift: true);
+
+/// Asks for the note, then marks; the toast says where it went.
+Future<void> showMarkProblem(BuildContext context) async {
+  final note = await showPopover<String>(context, at: Alignment.center, child: const MarkProblemCard());
+  if (note == null) return;
+  final coord = SessionState.instance.coordinator;
+  final inSession = await coord.markProblem(note);
+  coord.showToast(inSession ? 'Marked in the session log' : "Marked in this app's log");
+}
+
+/// The small card: a one-line note and Mark. Pops with the note (maybe
+/// empty), or nothing on Cancel / Esc.
+class MarkProblemCard extends StatefulWidget {
+  const MarkProblemCard({super.key});
+
+  @override
+  State<MarkProblemCard> createState() => _MarkProblemCardState();
+}
+
+class _MarkProblemCardState extends State<MarkProblemCard> {
+  final _note = TextEditingController();
+
+  @override
+  void dispose() {
+    _note.dispose();
+    super.dispose();
+  }
+
+  void _mark() => Navigator.of(context).pop(_note.text.trim());
+
+  @override
+  Widget build(BuildContext context) {
+    final muted = Theme.of(context).colorScheme.onSurfaceVariant;
+    return AppGlass(
+      key: const ValueKey('mark-problem-card'),
+      child: SizedBox(
+        width: 380,
+        child: Padding(
+          padding: const EdgeInsets.fromLTRB(16, 12, 16, 10),
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            crossAxisAlignment: CrossAxisAlignment.stretch,
+            children: [
+              const Text('Mark a problem', style: TextStyle(fontWeight: FontWeight.w600, fontSize: 14)),
+              const SizedBox(height: 4),
+              Text("Puts a marker in the server's session log right now, so whoever reads it finds the moment.",
+                  style: TextStyle(color: muted, fontSize: 12)),
+              const SizedBox(height: 8),
+              TextField(
+                key: const ValueKey('mark-problem-note'),
+                controller: _note,
+                autofocus: true,
+                maxLength: RelayConstants.maxProblemNoteLength,
+                decoration: const InputDecoration(
+                  isDense: true,
+                  hintText: 'What happened? (optional)',
+                  counterText: '',
+                ),
+                onSubmitted: (_) => _mark(),
+              ),
+              const SizedBox(height: 8),
+              Row(
+                mainAxisAlignment: MainAxisAlignment.end,
+                children: [
+                  TextButton(onPressed: () => Navigator.of(context).pop(), child: const Text('Cancel')),
+                  const SizedBox(width: 8),
+                  FilledButton.tonal(
+                    key: const ValueKey('mark-problem-go'),
+                    onPressed: _mark,
+                    child: const Text('Mark'),
+                  ),
+                ],
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}
+
+/// "Mark a problem" as a quiet row button (the ⚙ card, Settings → About).
+class MarkProblemButton extends StatelessWidget {
+  final bool outlined;
+  const MarkProblemButton({super.key, this.outlined = false});
+
+  @override
+  Widget build(BuildContext context) {
+    const icon = Icon(Icons.flag_outlined, size: 18);
+    const label = Text('Mark a problem');
+    void open() => showMarkProblem(context);
+    return Tooltip(
+      message: 'Ctrl+Shift+B',
+      child: outlined
+          ? OutlinedButton.icon(key: const ValueKey('mark-problem'), onPressed: open, icon: icon, label: label)
+          : TextButton.icon(key: const ValueKey('mark-problem'), onPressed: open, icon: icon, label: label),
+    );
+  }
+}

apps/desktop/lib/src/shell/session_player.dart

@@ -29,6 +29,7 @@ import '../widgets/app_keys.dart';
 import '../widgets/text_focus.dart';
 import '../widgets/window_buttons.dart';
 import 'avatar.dart';
+import 'mark_problem.dart';
 import 'motion.dart';
 import 'now_playing_title.dart';
 import 'player_status.dart';
@@ -627,6 +628,7 @@ class _SessionPlayerState extends State<SessionPlayer> {
             (title: 'Change video', hint: null, run: widget.onChangeVideo),
             (title: 'Chat & activity', hint: 'Tab', run: _toggleChat),
             (title: 'Reload video', hint: 'Ctrl+R', run: _reloadVideo),
+            (title: 'Mark a problem', hint: 'Ctrl+Shift+B', run: () => showMarkProblem(context)),
             (title: 'Mark everyone ready', hint: null, run: coord.forcePlayAll),
             (title: 'Fullscreen', hint: 'F', run: widget.onToggleFullscreen),
             (title: 'Leave server', hint: 'Esc', run: widget.onLeave),

apps/desktop/lib/src/state/server_isolate.dart

@@ -33,10 +33,12 @@ class ServerIsolate {
 
   /// Spawns the server and waits until it listens. Throws a
   /// [StateError] with the server's message if it cannot start.
-  /// [loopbackOnly]: 127.0.0.1 only (the solo session).
+  /// [loopbackOnly]: 127.0.0.1 only (the solo session). [logDir]: where
+  /// the server writes its session log (none when null).
   static Future<ServerIsolate> start(
     AppConfig config, {
     bool loopbackOnly = false,
+    String? logDir,
     required void Function(String line) onLog,
     required void Function(String error) onCrash,
     Duration timeout = const Duration(seconds: 15),
@@ -85,7 +87,7 @@ class ServerIsolate {
     final Isolate isolate;
     try {
       isolate = await Isolate.spawn(
-          _serverMain, ({...config.toMap(), if (loopbackOnly) 'loopbackOnly': true}, events.sendPort),
+          _serverMain, ({...config.toMap(), if (loopbackOnly) 'loopbackOnly': true, 'logDir': ?logDir}, events.sendPort),
           errorsAreFatal: false,
           onError: errors.sendPort,
           onExit: exit.sendPort,

apps/desktop/lib/src/state/session_state.dart

@@ -10,6 +10,7 @@ import '../jellyfin/accounts.dart';
 import '../jellyfin/session_media.dart';
 import '../screens/home/health_probe.dart';
 import '../screens/home/picked_media.dart';
+import '../platform/app_log.dart' show appLogDir;
 import '../playback/yt_dlp_app.dart';
 import '../sfx/sfx.dart';
 import '../sfx/sound_bank.dart';
@@ -379,6 +380,9 @@ class SessionState {
             ytDlpDir: await _sharedYtDlpDir(),
           ),
           loopbackOnly: soloSession,
+          // Its session log (every member's shared diagnostics and its own
+          // records) goes next to the app's; not for a solo session.
+          logDir: soloSession ? null : appLogDir,
           // Its records join the app's log as `server.<logger>`.
           onLog: (line) => relogLine('server', line),
           onCrash: (cause) => _onServerCrash(server, cause),

apps/desktop/lib/src/state/settings.dart

@@ -28,6 +28,7 @@ const _keySoundPresetFor = 'soundPresetFor';
 const _keyUnreadyOnSwap = 'unreadyOnSwap';
 const _keyIdleSitsOut = 'idleSitsOut';
 const _keyChatPopups = 'chatPopups';
+const _keyShareDiagnostics = 'shareDiagnostics';
 
 enum HwdecMode { auto, off, custom }
 
@@ -70,6 +71,9 @@ class AppSettings {
   /// A 2 px progress line at the bottom of the video while the controls
   /// are hidden (both designs). Applies live.
   final progressLine = signal(true);
+  /// Send this app's log lines to the server's session log while in a
+  /// session (never chat). Off: nothing is sent but a note that it is off.
+  final shareDiagnostics = signal(true);
   /// Chat message toasts (default: only when paused). Applies live.
   final chatPopups = signal(ChatPopups.paused);
   /// App sounds (`sfx/`): 0..1, 0 = silent.
@@ -129,6 +133,8 @@ class AppSettings {
       if (hideRe is bool) hideReReleases.value = hideRe;
       final line = box.get(_keyProgressLine);
       if (line is bool) progressLine.value = line;
+      final share = box.get(_keyShareDiagnostics);
+      if (share is bool) shareDiagnostics.value = share;
       final popups = box.get(_keyChatPopups);
       chatPopups.value = ChatPopups.values.where((m) => m.name == popups).firstOrNull ?? ChatPopups.paused;
       final vol = box.get(_keySoundVolume);
@@ -203,6 +209,11 @@ class AppSettings {
     _put(_keyProgressLine, on);
   }
 
+  void setShareDiagnostics(bool on) {
+    shareDiagnostics.value = on;
+    _put(_keyShareDiagnostics, on);
+  }
+
   void setChatPopups(ChatPopups mode) {
     chatPopups.value = mode;
     _put(_keyChatPopups, mode.name);

apps/desktop/lib/src/widgets/app_keys.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 
+import '../shell/mark_problem.dart';
 import '../state/session_state.dart';
 import 'text_focus.dart';
 
@@ -15,11 +16,12 @@ Map<ShortcutActivator, Intent> get appShortcuts => {
       const SingleActivator(LogicalKeyboardKey.space): const DoNothingIntent(),
     };
 
-/// The window's two app-wide keys, ahead of whatever has focus: while in a
+/// The window's app-wide keys, ahead of whatever has focus: while in a
 /// server, Space is ready / not ready and Tab opens or closes the chat,
 /// on every tab and in every player mode. Not while a text field has
 /// focus (the chat field handles Tab and Esc itself) nor while a dialog or
-/// menu is in front of [child].
+/// menu is in front of [child]. Ctrl+Shift+B ([markProblemKey]) marks a
+/// problem anywhere, a text field focused or not.
 class AppKeys extends StatefulWidget {
   /// Who toggles the chat, latest first: the strip while it is shown, the
   /// full player in fullscreen (both hold the shell's toggle).
@@ -53,6 +55,11 @@ class _AppKeysState extends State<AppKeys> {
   bool _key(KeyEvent event) {
     if (event is! KeyDownEvent || !mounted) return false;
     final key = event.logicalKey;
+    if (markProblemKey.accepts(event, HardwareKeyboard.instance)) {
+      if (ModalRoute.of(context)?.isCurrent == false) return false;
+      showMarkProblem(context);
+      return true;
+    }
     if (key != LogicalKeyboardKey.space && key != LogicalKeyboardKey.tab) return false;
     if (SessionState.instance.route.peek() != AppRoute.session) return false;
     if (ModalRoute.of(context)?.isCurrent == false) return false;

apps/desktop/test/app_keys_test.dart

@@ -65,4 +65,24 @@ void main() {
     expect(readies, 1);
     expect(panel, findsNothing, reason: 'Space pressed a focused chat button');
   });
+
+  testWidgets('Ctrl+Shift+B opens Mark a problem; Esc closes it unmarked', (tester) async {
+    await tester.pumpWidget(MaterialApp(
+      theme: ThemeData.dark(),
+      shortcuts: appShortcuts,
+      home: const AppKeys(child: Scaffold(body: SizedBox())),
+    ));
+    final card = find.byKey(const ValueKey('mark-problem-card'));
+    await tester.sendKeyDownEvent(LogicalKeyboardKey.controlLeft);
+    await tester.sendKeyDownEvent(LogicalKeyboardKey.shiftLeft);
+    await tester.sendKeyEvent(LogicalKeyboardKey.keyB);
+    await tester.sendKeyUpEvent(LogicalKeyboardKey.shiftLeft);
+    await tester.sendKeyUpEvent(LogicalKeyboardKey.controlLeft);
+    await tester.pumpAndSettle();
+    expect(card, findsOneWidget);
+    expect(textInputFocused(), isTrue, reason: 'the note field takes the keys');
+    await tester.sendKeyEvent(LogicalKeyboardKey.escape);
+    await tester.pumpAndSettle();
+    expect(card, findsNothing);
+  });
 }