name: Debug Data Loss description: DEBUG mysteriously disappearing tasks using the taskDisappearanceLogger. Use when tasks vanish without user deletion, data seems to be lost, or you need to track what's modifying the task array. Provides comprehensive logging of all task array operations.

Debug Data Loss

When to Use This Skill

Activate this skill when:

• Tasks are mysteriously disappearing without user deletion
• Data loss is suspected but can't be reproduced
• You need to track what code paths are modifying tasks.value
• Cross-tab sync or undo/redo is suspected of causing data loss

Task Disappearance Logger

Location: src/utils/taskDisappearanceLogger.ts

The logger tracks all modifications to the task array and identifies when tasks disappear without explicit user deletion.

Current Status

The logger is auto-enabled on app startup (added for BUG-020 investigation).

• Auto-enable code: src/main.ts (lines 74-79)
• Periodic snapshots every 30 seconds when enabled
• Persists logs to localStorage

Browser Console API

// Enable/Disable monitoring
window.taskLogger.enable()
window.taskLogger.disable()

// Check for disappeared tasks (most important!)
window.taskLogger.getDisappearedTasks()

// Get summary of all logging
window.taskLogger.printSummary()

// Search for a specific task in history
window.taskLogger.findTaskInHistory("task title or id")

// Get all logs
window.taskLogger.getLogs()

// Get all snapshots
window.taskLogger.getSnapshots()

// Export logs for analysis
window.taskLogger.exportLogs()

// Clear all history
window.taskLogger.clearHistory()

What Gets Logged

The logger wraps all tasks.value = assignments in these files:

Log Sources

Each log entry includes a source field identifying where the change occurred:

Analyzing Disappearances

When a task disappears, the logger records:

interface DisappearedTask {
  task: { id, title, status, projectId }
  disappearedAt: number      // Timestamp when it vanished
  lastSeenAt: number         // Timestamp of last snapshot containing it
  lastSeenSource: string     // What operation was happening
  disappearedDuring: string  // What operation caused disappearance
  stackTrace?: string        // JavaScript stack trace
  wasUserDeletion: boolean   // false = suspicious disappearance
}

Debugging Workflow

1. Enable logging (auto-enabled for BUG-020):

   window.taskLogger.enable()
   

2. Use the app normally - reproduce the issue if possible

3. Check for disappeared tasks:

   const disappeared = window.taskLogger.getDisappearedTasks()
   console.log(disappeared)
   

4. Analyze the source:

   • Look at disappearedDuring to see what operation caused it
   • Check stackTrace to see the exact code path
   • Compare lastSeenSource vs disappearedDuring

5. Export for detailed analysis:

   const logs = window.taskLogger.exportLogs()
   // Copy/paste to a file for analysis
   

Removing Auto-Enable

Once BUG-020 is resolved, remove auto-enable from src/main.ts:

// DELETE these lines (around lines 74-79):
setTimeout(() => {
  taskDisappearanceLogger.enable()
  console.log('%c[TASK-LOGGER] Auto-enabled for BUG-020 investigation', 'color: #4CAF50; font-weight: bold')
}, 2000)

Related

• BUG-020: Tasks randomly disappearing without user deletion
• TASK-022: Task Disappearance Logger & Investigation
• TASK-024: Review Task Disappearance Logs (scheduled review)
• Skill: dev-fix-task-store - General task store debugging