Interactive UI creates duplicate messages on button press instead of editing in-place

[zhou-zhichao]

Problem

When interacting with interactive UIs (AskUserQuestion, ExitPlanMode, Permission Prompt, etc.) via Telegram inline keyboard buttons, each button press (Up/Down/Enter/Space/Tab) creates a new message instead of editing the existing one. This results in multiple interactive UI messages accumulating in the topic.

Root Cause

In src/ccbot/handlers/interactive_ui.py, the handle_interactive_ui function (line ~193-210) tries to edit the existing message, but catches all exceptions and falls through to sending a new message:

existing_msg_id = _interactive_msgs.get(ikey)
if existing_msg_id:
    try:
        await bot.edit_message_text(...)
        return True
    except Exception:
        # Edit failed — clears msg_id but does NOT delete the old message
        _interactive_msgs.pop(ikey, None)
        # Falls through to send a NEW message

Two issues here:

1. "Message is not modified" error: When the terminal content hasn't changed after a button press, Telegram raises BadRequest: Message is not modified. The broad except Exception catches this and creates a duplicate message unnecessarily.

2. Old message not deleted on other failures: When the edit genuinely fails (message deleted externally, etc.), the old message is not deleted before sending a new one, leaving a stale UI message in the chat.

Suggested Fix

existing_msg_id = _interactive_msgs.get(ikey)
if existing_msg_id:
    try:
        await bot.edit_message_text(...)
        _interactive_mode[ikey] = window_id
        return True
    except BadRequest as e:
        if "Message is not modified" in str(e):
            # Content unchanged — keep existing message, no action needed
            _interactive_mode[ikey] = window_id
            return True
        # Other edit failure — delete old message before sending new
        logger.debug("Edit failed for interactive msg %s: %s, sending new", existing_msg_id, e)
        _interactive_msgs.pop(ikey, None)
        try:
            await bot.delete_message(chat_id=chat_id, message_id=existing_msg_id)
        except Exception:
            pass
    except Exception:
        logger.debug("Edit failed for interactive msg %s, sending new", existing_msg_id)
        _interactive_msgs.pop(ikey, None)
        try:
            await bot.delete_message(chat_id=chat_id, message_id=existing_msg_id)
        except Exception:
            pass

This ensures only one interactive UI message exists at any time.

Expected Behavior

• Button presses should edit the existing interactive UI message in-place
• If content hasn't changed, keep the existing message (no duplicate)
• If edit fails for other reasons, delete the old message before sending a new one
• There should always be at most one interactive UI message per topic