With a gate on the first machine and a rollback after it, a module's build rolls out by
default. The ones kept back say why: the network path a rollback could not cross, the
providers every consumer on a machine drops with, and the stores holding the photos.
A merge's deleted files are announced, so a module whose manifest went is forgotten
rather than asked to build (the public-acme plan failure).
With the poll the only announcer of a merge, its cost showed: every 30 s it
asked every repository for its pull requests, a pass outlasted the tick, and
passes piled up beside each other — a merge was announced four and a half
minutes late, and two passes at once could each announce it. A pass now asks
only repositories updated since a minute before the last look, and the next
pass starts when this one ends. hq issue 250.
jochen