internal/

Package candidates holds the per-replica bounded set of step candidates produced by the engine's refillers.

Package claimstracker records which steps a replica has a claim CAS in flight on, so a sibling worker that pops the same candidate can skip it instead of paying a round trip to lose the CAS.

Package database owns the engine's sharded SQL connections: it opens and migrates every shard, routes by 1-based shard index, fans an operation out over all shards, and closes them.

Package enginetest holds the engine test helpers that are shared across package boundaries - by the white-box tests that stay in package engine AND by the black-box tests in the fixtures package.

Package faninmap derives the fan-out -> fan-in convergence map of a workflow graph: which node a given fan-out source's branches converge on.

Package keys encodes and decodes the engine's composite flow and step keys.

Package latch parks callers on a key until something reports that key done.

Package lru provides a small thread-safe LRU cache with a per-entry TTL.

Package peers reports the fleet sharing one shard's database, from that shard's replica registry.

Package pipeline runs one shard's supply cycle: it looks at what is due, asks the planner what it may serve, fetches that, and pushes it to the candidate cache the workers drain.

Package piston supplies step candidates from one shard.

Package planner decides which work a shard may dispatch, given what every shard last reported.

Package staterefs stores a large carried state field once instead of copying it into every step that merely passes it along.

Package turnstile bounds how many callers may hold a resource at once AND decides which waiter is admitted next: the lowest priority band, and within a band the job that started earliest.

Package workers holds the demand side of dispatch: a CREW of goroutines that pop step candidates from the cache and hand each to one callback.