fix(client): keep flat sessions ordered by recency

packages/client/ui-workspace/src/client/WorkspaceBrowser.tsx

@@ -36,9 +36,6 @@ const SEARCH_DEBOUNCE_MS = 250
 const SEARCH_QUERY_MAX_CODE_UNITS = 500
 /** Session rows visible per Workspace before the local overflow control. */
 const COLLAPSED_SESSION_LIMIT = 5
-const EMPTY_WORKSPACE_EXPANSION: Readonly<Record<string, boolean>> = Object.freeze({})
-const EMPTY_RECENT_SESSION_ORDER: Readonly<Record<string, readonly string[]>> = Object.freeze({})
-const EMPTY_RECENT_SESSION_UPDATED_AT: Readonly<Record<string, Readonly<Record<string, number>>>> = Object.freeze({})
 
 /** Keep controlled input and RPC payload inside the session.search wire contract. */
 function sanitizeSearchQuery(value: string): string {
@@ -245,7 +242,11 @@ function SessionTree({
         nextOrder.sort((a, b) => compareSessionRecency(a, b, list.byId))
       } else {
         const promoted = sessionIds
-          .filter((id) => previousUpdatedAt[id] === undefined || list.byId[id]!.updatedAt > previousUpdatedAt[id]!)
+          .filter((id) => {
+            const session = list.byId[id]
+            return session !== undefined
+              && (previousUpdatedAt[id] === undefined || session.updatedAt > previousUpdatedAt[id])
+          })
           .sort((a, b) => compareSessionRecency(a, b, list.byId))
         if (promoted.length > 0) {
           const promotedIds = new Set(promoted)
@@ -253,7 +254,10 @@ function SessionTree({
         }
       }
       const nextUpdatedAt: Record<string, number> = {}
-      for (const id of sessionIds) nextUpdatedAt[id] = list.byId[id]!.updatedAt
+      for (const id of sessionIds) {
+        const session = list.byId[id]
+        if (session !== undefined) nextUpdatedAt[id] = session.updatedAt
+      }
       const orderChanged = previousOrder === undefined
         || nextOrder.length !== previousOrder.length
         || nextOrder.some((id, index) => id !== previousOrder[index])
@@ -299,7 +303,7 @@ function SessionTree({
       const nextOrder = account.sessionIds.filter(id => id !== activeDrag.sessionId)
       const insertAt = anchor === undefined ? nextOrder.length : nextOrder.indexOf(anchor)
       nextOrder.splice(insertAt === -1 ? nextOrder.length : insertAt, 0, activeDrag.sessionId)
-      setRecentSessionOrder(activeDrag.workspaceId as string, nextOrder.map(id => id as string))
+      setRecentSessionOrder(activeDrag.workspaceId, nextOrder.map(id => id as string))
       return
     }
     insertSessionBefore(activeDrag.workspaceId, activeDrag.sessionId, anchor).catch((reason: unknown) => {
@@ -465,13 +469,13 @@ function SessionTree({
 }
 
 /** The flat "In one list" body: every session a top-level row, newest-first. */
-function FlatList({ useSessions, open, forkSession, onSessionRename, onSessionArchive, archivedSessionIds, orderBy, t }: Pick<
+function FlatList({ useSessions, open, forkSession, onSessionRename, onSessionArchive, archivedSessionIds, t }: Pick<
-  SessionTreeProps, 'useSessions' | 'open' | 'forkSession' | 'onSessionRename' | 'onSessionArchive' | 'archivedSessionIds' | 'orderBy' | 't'
+  SessionTreeProps, 'useSessions' | 'open' | 'forkSession' | 'onSessionRename' | 'onSessionArchive' | 'archivedSessionIds' | 't'
 >) {
   const list = useSessions(s => s)
   const rows = useMemo(
-    () => deriveFlat(list, archivedSessionIds, orderBy),
+    () => deriveFlat(list, archivedSessionIds),
-    [list, archivedSessionIds, orderBy],
+    [list, archivedSessionIds],
   )
   const now = Date.now()
   return (
@@ -604,16 +608,13 @@ export function WorkspaceBrowser({
   // flow reads): a composition without a picking affordance can add nothing.
   const directoryFlowAvailable = useDirectoryFlow(occupied => occupied)
   const groupBy = useStore(s => s.groupBy)
-  // A live HMR handoff can retain the pre-ordering store instance until the
+  const orderBy = useStore(s => s.orderBy)
-  // slot is remounted; manual is the established Workspace order.
-  const orderBy = useStore(s => s.orderBy ?? 'manual')
   // A flat list has no single Workspace account to drag. Keep the stored
   // grouped preference intact while presenting the flat list by recency.
   const effectiveOrderBy = groupBy === 'flat' && orderBy === 'manual' ? 'updated' : orderBy
-  // HMR can retain the preceding view-store instance until the slot remounts.
+  const workspaceExpansion = useStore(s => s.workspaceExpansion)
-  const workspaceExpansion = useStore(s => s.workspaceExpansion ?? EMPTY_WORKSPACE_EXPANSION)
+  const recentSessionOrder = useStore(s => s.recentSessionOrder)
-  const recentSessionOrder = useStore(s => s.recentSessionOrder ?? EMPTY_RECENT_SESSION_ORDER)
+  const recentSessionUpdatedAt = useStore(s => s.recentSessionUpdatedAt)
-  const recentSessionUpdatedAt = useStore(s => s.recentSessionUpdatedAt ?? EMPTY_RECENT_SESSION_UPDATED_AT)
   // The query outlives the tree and the input (both wide-only) so collapsing
   // does not silently drop an in-progress filter.
   const [query, setQuery] = useState('')
@@ -958,7 +959,7 @@ export function WorkspaceBrowser({
               <FlatList
                 useSessions={useSessions} open={open} forkSession={forkSession}
                 onSessionRename={onSessionRename} onSessionArchive={onSessionArchive}
-                archivedSessionIds={archivedSessionIds} orderBy={effectiveOrderBy} t={t}
+                archivedSessionIds={archivedSessionIds} t={t}
               />
             )
             : (

packages/client/ui-workspace/src/client/tree.ts

@@ -208,8 +208,8 @@ function sessionNode(
 /**
  * Derive the workspace browser groups with every session as a top-level row.
  *
- * Every group shows; sessions populate under expanded groups, preserving
+ * Every group shows; sessions populate under expanded groups in the selected
- * Host account order. Blank sessions are excluded except for the selected
+ * local order. Blank sessions are excluded except for the selected
  * provisional New Session row; archived sessions are excluded everywhere.
  * Content search lives outside this derivation
  * (see {@link deriveSearchResults}).
@@ -217,6 +217,7 @@ function sessionNode(
  * @param workspaces - real workspaces in stable Host order.
  * @param archivedSessionIds - registry-global archive set.
  * @param view - local expansion arrays.
+ * @param orderBy - local session ordering mode.
  * @returns group sections in render order.
  */
 export function deriveGroups(
@@ -263,7 +264,6 @@ export function deriveGroups(
 export function deriveFlat(
   list: SessionListState,
   archivedSessionIds: readonly SessionId[],
-  orderBy: SessionOrderBy = 'updated',
 ): SessionNode[] {
   const archived = new Set(archivedSessionIds)
   const descendants = indexSubagentDescendants(list.byId)
@@ -273,7 +273,7 @@ export function deriveFlat(
     if (s === undefined || !sessionVisible(s, list.current, archived)) continue
     rows.push(s)
   }
-  sortSessions(rows, orderBy === 'manual' ? 'updated' : orderBy)
+  sortSessions(rows)
   return rows.map(session => sessionNode(session, descendants))
 }