Cleanup Patterns

When Cleanup Is Needed

Blocks that use:

• •Timers
• •Media players
• •UI windows
• •File handles
• •Network connections
• •Cached data

BlockProcessor.cleanup()

Override in BlockProcessor. Called when:

• •Block is removed
• •Project is unloaded

def cleanup(self, block: Block) -> None:
    """Clean up resources for this block."""
    if hasattr(self, '_timer') and self._timer:
        self._timer.stop()
        self._timer.deleteLater()
        self._timer = None
    if hasattr(self, '_player') and self._player:
        self._player.stop()
        self._player.deleteLater()
        self._player = None

Qt Objects

Use deleteLater() for Qt objects - never delete directly:

widget.deleteLater()
timer.deleteLater()

Pattern: Capture Then Clear

def cleanup(self, block: Block) -> None:
    timer = getattr(self, '_timer', None)
    if timer:
        timer.stop()
        timer.deleteLater()
        delattr(self, '_timer')

Common Resources

Checklist

• • Identify all resources in block
• • Implement cleanup() override
• • Call stop/close before deleteLater for Qt
• • Clear references to prevent leaks
• • Test: add block, remove block, verify no leaks

Reference

• •SUMMARY: AgentAssets/modules/commands/cleanup/SUMMARY.md
• •Block implementation: echozero-block-implementation skill