Problem (live 2026-05-26 screenshot): player drops a block in front of
the bot mid-path. mineflayer-pathfinder computes the path once when
goto() is called and never recomputes for world changes. Bot pushes
forward against the new block until the 30–60 s goto timeout fires,
visible as the bot just standing there pressing W.
Fix — runtime/pathfinder-watchdog.js: per-bot poll loop (2 s tick) that
runs while bot.pathfinder.goal is non-null. Tracks horizontal position.
If movement < 0.5 blocks for > 6 s after an initial 1.5 s grace,
forces a replan: setGoal(null) + setGoal(<same goal>) on a 250 ms
delay. That makes the planner rebuild the path against the current
world, so it routes around the new block — or, with canDig=true in our
profiles, digs through it. Capped at 3 replans per goal so a genuinely
unreachable target still bubbles up to the caller's timeout.
Side benefit: catches mineflayer-pathfinder issue #222 ("path hangs
on unreachable goal") much earlier than our 45 s goto wrappers.
Wired into bot.js on the "spawn" event and stopped on gracefulExit.
7 new unit tests cover the polling math + replan cap. 197/197 green.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
