fix(sync): prefer freshest session status and persist active-now list

packages/ui/src/components/session/SessionSidebar.tsx

@@ -57,7 +57,13 @@ import {
 } from './sidebar/ConfirmDialogs';
 import { type SessionGroup, type SessionNode } from './sidebar/types';
 import {
+  type ActiveNowEntry,
+  addActiveNowSession,
+  deriveActiveNowSessions,
   deriveLiveActiveNowSessions,
+  persistActiveNowEntries,
+  pruneActiveNowEntries,
+  readActiveNowEntries,
 } from './sidebar/activitySections';
 import {
   compareSessionsByPinnedAndTime,
@@ -129,6 +135,7 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
     () => new Map(),
   );
   const safeStorage = React.useMemo(() => getSafeStorage(), []);
+  const [activeNowEntries, setActiveNowEntries] = React.useState<ActiveNowEntry[]>(() => readActiveNowEntries(safeStorage));
   const [collapsedProjects, setCollapsedProjects] = React.useState<Set<string>>(new Set());
 
   const [projectRepoStatus, setProjectRepoStatus] = React.useState<Map<string, boolean | null>>(new Map());
@@ -1011,10 +1018,45 @@ export const SessionSidebar: React.FC<SessionSidebarProps> = ({
   }, [projectSections, homeDirectory]);
 
   const activeNowSessions = React.useMemo(
+    () => deriveActiveNowSessions(activeNowEntries, new Map(sessions.map((session) => [session.id, session]))),
+    [activeNowEntries, sessions],
+  );
+
+  const liveActiveSessions = React.useMemo(
     () => deriveLiveActiveNowSessions(sessions, liveSessionStatuses),
     [liveSessionStatuses, sessions],
   );
 
+  React.useEffect(() => {
+    if (liveActiveSessions.length === 0) {
+      return;
+    }
+
+    setActiveNowEntries((prev) => {
+      const next = liveActiveSessions.reduce((entries, session) => addActiveNowSession(entries, session.id), prev);
+      if (next === prev) {
+        return prev;
+      }
+      persistActiveNowEntries(safeStorage, next);
+      return next;
+    });
+  }, [liveActiveSessions, safeStorage]);
+
+  React.useEffect(() => {
+    const allKnownSessionsById = new Map<string, Session>();
+    [...sessions, ...archivedSessions].forEach((session) => {
+      allKnownSessionsById.set(session.id, session);
+    });
+
+    const pruned = pruneActiveNowEntries(activeNowEntries, allKnownSessionsById);
+    if (pruned.length === activeNowEntries.length && pruned.every((entry, index) => entry.sessionId === activeNowEntries[index]?.sessionId)) {
+      return;
+    }
+
+    setActiveNowEntries(pruned);
+    persistActiveNowEntries(safeStorage, pruned);
+  }, [activeNowEntries, archivedSessions, safeStorage, sessions]);
+
   // Prefetch is wired below, after recentSessionIds is computed.
 
   const activitySections = React.useMemo(() => {

packages/ui/src/sync/__tests__/live-aggregate.test.js

@@ -58,6 +58,27 @@ describe('live aggregate', () => {
     expect(findLiveSessionStatus(states, 'ses-2')?.type).toBe('retry')
   })
 
+  it('lets a fresher idle snapshot override a stale busy status', () => {
+    const states = [
+      {
+        session: [session('ses-1', '/a', 10)],
+        session_status: {
+          'ses-1': { type: 'busy' },
+        },
+      },
+      {
+        session: [session('ses-1', '/a', 30)],
+        session_status: {
+          'ses-1': { type: 'idle' },
+        },
+      },
+    ]
+
+    const statuses = aggregateLiveSessionStatuses(states)
+    expect(statuses['ses-1']?.type).toBe('idle')
+    expect(findLiveSessionStatus(states, 'ses-1')?.type).toBe('idle')
+  })
+
   it('derives active-now sessions from live statuses instead of persisted history', () => {
     const sessions = [
       session('ses-1', '/a', 20),

packages/ui/src/sync/live-aggregate.ts

@@ -47,6 +47,36 @@ const getStatusMessage = (status: SessionStatus | undefined): string | null => {
   return typeof message === 'string' ? message : null
 }
 
+type StatusCandidate = {
+  status: SessionStatus
+  sessionUpdatedAt: number
+}
+
+const getStatusCandidate = (state: LiveStateSlice, sessionId: string): StatusCandidate | null => {
+  const status = state.session_status?.[sessionId]
+  if (!status) {
+    return null
+  }
+
+  const session = state.session.find((candidate) => candidate.id === sessionId)
+  return {
+    status,
+    sessionUpdatedAt: session ? getSessionUpdatedAt(session) : -1,
+  }
+}
+
+const shouldReplaceStatusCandidate = (current: StatusCandidate | undefined, next: StatusCandidate): boolean => {
+  if (!current) {
+    return true
+  }
+
+  if (next.sessionUpdatedAt !== current.sessionUpdatedAt) {
+    return next.sessionUpdatedAt > current.sessionUpdatedAt
+  }
+
+  return getStatusPriority(next.status) >= getStatusPriority(current.status)
+}
+
 export const areSessionListsEquivalent = (left: Session[], right: Session[]): boolean => {
   if (left === right) {
     return true
@@ -116,17 +146,27 @@ export function aggregateLiveSessions(states: Iterable<LiveStateSlice>): Session
 }
 
 export function aggregateLiveSessionStatuses(states: Iterable<LiveStateSlice>): Record<string, SessionStatus> {
-  const statuses: Record<string, SessionStatus> = {}
+  const candidates = new Map<string, StatusCandidate>()
 
   for (const state of states) {
-    for (const [sessionId, status] of Object.entries(state.session_status ?? {})) {
-      const current = statuses[sessionId]
-      if (!current || getStatusPriority(status) >= getStatusPriority(current)) {
-        statuses[sessionId] = status
+    for (const sessionId of Object.keys(state.session_status ?? {})) {
+      const next = getStatusCandidate(state, sessionId)
+      if (!next) {
+        continue
+      }
+
+      const current = candidates.get(sessionId)
+      if (shouldReplaceStatusCandidate(current, next)) {
+        candidates.set(sessionId, next)
       }
     }
   }
 
+  const statuses: Record<string, SessionStatus> = {}
+  for (const [sessionId, candidate] of candidates) {
+    statuses[sessionId] = candidate.status
+  }
+
   return statuses
 }
 
@@ -157,16 +197,16 @@ export function findLiveSessionStatus(
     return undefined
   }
 
-  let match: SessionStatus | undefined
+  let match: StatusCandidate | undefined
   for (const state of states) {
-    const status = state.session_status?.[sessionID]
-    if (!status) {
+    const next = getStatusCandidate(state, sessionID)
+    if (!next) {
       continue
     }
-    if (!match || getStatusPriority(status) >= getStatusPriority(match)) {
-      match = status
+    if (shouldReplaceStatusCandidate(match, next)) {
+      match = next
     }
   }
 
-  return match
+  return match?.status
 }