Slackbot: ignore edits while initial response is in progress

[zzstoatzz]

Summary\n- Prevent duplicate responses when users edit their original mention mid-run\n- Cross-process dedupe via tiny sqlite status in _internal.thread_status (idempotency key = root thread_ts)\n- If an edit arrives while in progress, post a polite notice asking for follow-ups as new thread messages\n- Keep app logic lean: minimal changes to api.py; no changes to core DB class\n\nDesign\n- Adds _internal/thread_status.py with ensure_schema/try_acquire/get_status/mark_completed. Schema is created lazily.\n- api.py acquires per-thread key before processing; on conflict, checks status: in_progress => send edit-ignored message; completed => skip.\n- Uses the existing sqlite DB file from settings; no new service or dep.\n- Adds optional SlackEvent.subtype for future-proof edit detection; otherwise behavior is based on duplicate events regardless of subtype.\n\nNotes\n- Keeps example scope small and avoids sprawl into core.\n- Passes ruff and format hooks.\n- Happy to adjust the copy for the polite notice or extend dedupe keying if you want to incorporate client_msg_id.\n

[Copilot]

Pull Request Overview

This PR implements cross-process deduplication for Slack events to prevent duplicate responses when users edit their original messages while the bot is processing. The solution uses a lightweight SQLite table to track thread processing status.

• Add thread status tracking with in_progress/completed states stored in SQLite
• Implement cross-process acquire mechanism using atomic INSERT OR IGNORE operations
• Send polite notice to users when edits are detected during processing

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
examples/slackbot/src/slackbot/slack.py	Adds optional subtype field to SlackEvent model for future edit detection
examples/slackbot/src/slackbot/core.py	Adds comment explaining thread status is handled in api.py
examples/slackbot/src/slackbot/api.py	Integrates thread status checking and user notification logic into message handler
examples/slackbot/src/slackbot/_internal/thread_status.py	New module providing SQLite-backed thread status tracking functions

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[Copilot]

The type ignore comment is unnecessary. The return type annotation already handles the None case correctly, and mypy should understand that row[0] will be a Status when row is not None.

Suggested change

	return row[0] if row else None # type: ignore[return-value]
	return row[0] if row else None

[Copilot]

The assertion message should be more descriptive and actionable. Consider changing to 'Event channel cannot be None when posting notification message' or use proper error handling instead of assertion.

Suggested change

	assert event.channel is not None, (
	"Event channel is None when posting edit-ignored notice"
	)
	if event.channel is None:
	logger.error("Event channel is None when posting edit-ignored notice")
	return Completed(
	message="Cannot post edit-ignored notice: event channel is None",
	name="SKIPPED_NO_CHANNEL",
	data=dict(thread_ts=root_ts),
	)

[Copilot]

The warning message should include the specific error details for better debugging. Consider logging the exception: logger.warning('Failed to mark thread as completed', exc_info=True) or logger.warning('Failed to mark thread as completed: %s', e).

Suggested change

	logger.warning("Failed to mark thread as completed")
	logger.warning("Failed to mark thread as completed", exc_info=True)