SentBuilds answers from the keys of the node's assignments that name a commit, known when the node was sent anything and no key says its commit unknown. A send that names its builds writes the commit, build and rollout on each carried module's key (a module nothing assigns gets a standing key marked pulled-in, never a state) and clears what every other key of the node named; a send by hand writes sent-unknown, a time, on every key and clears their commits. A failed write of these fails the record of the send. node.sent_builds is no longer written. The plan pass ends a pulled-in key only when no send carries it.
A wait for a build is the value of <node>.<module> with state pending and a pending object (id p-<unix nanoseconds>, a string), so every reader that skips a value with a state skips it, and the controller's own lists skip it through Stands. The transitions are compare-and-set on the key's revision (claim, release, settle, repoint, mark); assigning over a wait carries it into the value that stands, applied when it was waiting; a plan pass never overwrites it; one open wait per machine and module, and a key that holds the module refuses a new one. The table is no longer read or written, ForgetEndedPending is gone (no key is removed), and a wait of a machine the store dropped is none. Callers change type only; their conditions are the next issue.
jschoubben