fix(mothership): stabilize task sidebar ordering on selection

[waleedlatif1]

Summary

• drop keepPreviousData from useTasks — was on a static key, caused stale-then-snap reorders on invalidation
• remove list invalidation from useMarkTaskRead/useMarkTaskUnread — server only flips lastSeenAt, optimistic update is sufficient
• validate SSE task_status payload before invalidating the task list — drop bogus events instead of triggering a refetch
• use selectTaskOnly in sidebar click handler so non-shift clicks match the rest of the selection model (clears workflow/folder selections, populates selectedTasks)

Type of Change

• Bug fix

Testing

Tested manually. 8/8 unit tests pass (hooks/queries/tasks.test.ts, hooks/use-task-events.test.ts).

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
docs	Skipped		Apr 27, 2026 7:27pm

[cursor]

PR Summary

Medium Risk
Touches task list caching/invalidation and SSE-driven refresh behavior, which can impact sidebar freshness and ordering if assumptions about server updates or event payloads are wrong. Changes are localized but affect core navigation UX.

Overview
Stabilizes the task sidebar by reducing unnecessary task-list refetches and aligning selection behavior.

useTasks no longer uses keepPreviousData, and useMarkTaskRead/useMarkTaskUnread now rely solely on optimistic updates (no list invalidation) to avoid refetch-driven reordering. handleTaskStatusEvent now validates/parses SSE payloads before invalidating the tasks list, and the sidebar’s normal click path uses useFolderStore.selectTaskOnly instead of manually resetting selection state.

^{Reviewed by Cursor Bugbot for commit f15f34b. Configure here.}

[greptile-apps]

Greptile Summary

Four targeted fixes that eliminate sidebar task-ordering jitter: drop keepPreviousData from the static-key useTasks query (per sim-queries.md), remove onSettled invalidation from the mark-read/unread mutations (optimistic update is provably equivalent to server state since only lastSeenAt is mutated), guard SSE task_status invalidation behind payload validation, and switch the sidebar single-click handler from a raw setState that cleared selectedTasks to selectTaskOnly which correctly adds the clicked task to the set and clears cross-entity selections.

Confidence Score: 5/5

Safe to merge — all changes are narrow, well-justified, and covered by existing tests.

No P0 or P1 findings. All four changes address a clear root cause with no observed regressions. The only remark is a P2 test-description nit.

No files require special attention.

Important Files Changed

Filename	Overview
apps/sim/app/workspace/[workspaceId]/w/components/sidebar/sidebar.tsx	Replaces raw setState (which set selectedTasks to an empty Set) with selectTaskOnly, correctly populating selectedTasks and clearing cross-selection state.
apps/sim/hooks/queries/tasks.ts	Removes keepPreviousData from static-key useTasks query (aligned with sim-queries.md) and drops onSettled invalidation from mark-read/unread mutations; both changes are well-justified in PR and thread.
apps/sim/hooks/use-task-events.ts	Moves invalidateQueries to after payload validation so malformed SSE events no longer trigger spurious list refetches.
apps/sim/hooks/use-task-events.test.ts	Tests updated to reflect new guard-before-invalidate behaviour; one test description is misleading about type-based branching that doesn't exist in the implementation.

Sequence Diagram

sequenceDiagram
    participant User
    participant Sidebar
    participant FolderStore
    participant SSE as SSE (task_status)
    participant TQ as TanStack Query
    participant Server

    User->>Sidebar: click task (no shift/meta)
    Sidebar->>FolderStore: selectTaskOnly(taskId)
    FolderStore-->>FolderStore: selectedTasks={taskId}, clear workflows/folders

    User->>Sidebar: mark task read
    Sidebar->>TQ: cancelQueries(taskList)
    TQ-->>TQ: optimistic update isUnread=false
    Sidebar->>Server: PATCH lastSeenAt
    Server-->>Sidebar: 200 OK
    Note over TQ: no invalidation — optimistic update is equivalent to server state

    SSE-->>Sidebar: task_status event
    Sidebar->>Sidebar: parseTaskStatusEventPayload(data)
    alt valid payload
        Sidebar->>TQ: invalidateQueries(taskList)
        TQ->>Server: refetch task list
    else invalid payload
        Sidebar->>Sidebar: log warn, return early
    end

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_{Reviews (2): Last reviewed commit: "fix(mothership): stabilize task sidebar ..." | Re-trigger Greptile}

[waleedlatif1]

@greptile

[waleedlatif1]

@cursor review

[cursor]

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^{Reviewed by Cursor Bugbot for commit f15f34b. Configure here.}