The building-id counter was the last piece of factory data living on Simulation
behind a callback: every construction site, every building, and every tile a
station entity claims took its id from a std::function BuildingSystem held, which
the arena and three test fixtures each had to supply.
It moves into FactoryState as nextBuildingId, handed out by
allocateBuildingId(state) in FactoryQueries beside the other operations over the
state. BuildingSystem's callback is gone; so are Simulation::allocateBuildingId
and ArenaSimulation::allocateBuildingId, whose remaining callers now allocate
from the state directly.
Checksum order is untouched: Simulation folds the counter where it always did.
What is left on BuildingSystem is the config, the belts, the RNG, and two
callbacks that reach genuinely outside the factory -- spawning a finished ship
into the entity model, and testing an output group against the unlock state.
Neither is factory data, so this is where the migration stops.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ne3mejABZoLWKLh8fgpM3x
forEachEmergingItem and forEachIncomingItem took a const FactoryState& and
touched no member of BuildingSystem: they read the state and the free geometry
helpers and nothing else. They are queries wearing a system's uniform, and their
one caller -- the renderer -- reached through getBuildings() to call them,
passing the state back in as an argument.
They move to FactoryQueries beside the rest of the read surface, and the renderer
calls them directly. With that, BuildingSystem answers no queries at all: its
const accessor on Simulation and on ArenaSimulation had no other user, so both
are gone. Nothing outside the command path can now reach the system.
No behaviour changes; the bodies move verbatim apart from two arrows in comments
that were non-ASCII.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ne3mejABZoLWKLh8fgpM3x
