034: A box a thread is working on is released or stopped only when forced

Status: accepted, 1 October 2026. Partly supersedes 033: only a thread that is working stops a release or a stop, and a person can force one.

Context

Since #111 a child thread can run on a box, and with “New box” (033) a thread runs on a box of its own. Releasing or stopping the box ends that thread’s work. 033 had box_release and box_stop refuse while any live thread ran on the box’s machine. But a thread that has finished stays live until it is archived, so it would keep its box from being released for no reason.

Decision

A thread is working on a box when it runs on the box’s BB machine, is neither archived nor deleted, and is busy (active, starting, pending or stopping) or waiting on a question to the user.
box_release, box_stop and bb box release refuse while a thread is working on the box, and name the thread. The agent is told to leave the box, or to ask the user.
A person can force it. The panel asks “Release anyway?” or “Stop anyway?”, naming the threads, and acts only on that answer. bb box release --force and the RPC’s force act at once.
An idle thread does not stop a release or a stop. The answer names it as having lost its machine, and suggests archiving it.
bb-box finds the threads with threads.list({ hostId, archived: false }). A box that is not a BB machine has none.

Consequences

An agent cannot end another thread’s work by mistake. A person can, after one question.
An idle thread whose box was released has no machine. It stays in BB until someone archives it.
The sweep (019) still releases a box whose thread was archived or deleted, without asking.