genesis_tree

The engine: a framework-agnostic, bare-VM Seed → Branch keyed-reconcile tree — Flutter's element/reconciliation model extracted to pure Dart, with no dart:ui and no Flutter dependency.

genesis_tree is the shared substrate the rest of genesis is built on. It owns the spine and refuses everything else.

The spine

Type	Role
`Seed`	immutable configuration (the Widget analogue) — `createBranch()`, `key`, `canUpdate`
`Branch`	the mounted, persistent node (the Element analogue) — identity, lifecycle, keyed reconcile, dirtiness, one abstract `performRebuild` hook
`TreeContext`	a separate capability handle passed to `build()` — never the `Branch` itself, so a handle held across an async gap fails loudly instead of acting on a stale node
`TreeOwner`	the scheduler — drains the dirty set depth-ordered; `flush()` returns the branches it rebuilt

Reconciliation is by key/identity, not structural diff: whole-(sub)tree re-emission becomes an identity-preserving patch (matched keys keep their Branch instance and live state; an identical() seed prunes its subtree).

Composition layer (experimental)

A thin composition layer on the spine, experimental and subject to change before 1.0:

StatelessSeed / StatefulSeed + State — the build-a-child-Seed elements;
InheritedSeed — ambient values down the tree (dependOnInheritedSeedOfExactType);
Watch<T> — a stream → rebuild builder;
Sprout — a hooks-style stateful primitive (useState → StateCell, useStream, useEffect, useMemo): one class, state declared inline in build, no separate State class. Additive — State<T> and Watch stay.

Branch purity invariant

Branch stays exactly identity + keyed reconcile + dirtiness + one abstract rebuild hook. It refuses the accretion that bloated Flutter's Element — no rendering, gestures, addPostFrameCallback-shaped lifecycle callbacks, timers, or listeners on the base. Build, state, effects, and scheduling live in composition subclasses or domains. (Inherited-value propagation is the one sanctioned base exception — a structural tree-query, lazily allocated.)

Status

Pre-1.0. The spine (Seed/Branch/TreeContext/TreeOwner/keyed reconcile) is stable in shape; the composition layer is experimental and may change.

License

BSD-3-Clause.