removing graph reference from node metadata

bind.go

@@ -156,7 +156,7 @@ func (b *bindMainIncr[A, B]) Stabilize(ctx context.Context) error {
 
 func (b *bindMainIncr[A, B]) Invalidate() {
 	for _, n := range b.bind.rhsNodes {
-		b.n.graph.invalidateNode(n)
+		graphFromScope(b).invalidateNode(n)
 	}
 }
 
@@ -199,7 +199,7 @@ func (b *bindLeftChangeIncr[A, B]) Stabilize(ctx context.Context) (err error) {
 		b.bind.main.parents = []INode{b}
 	}
 
-	if err = b.n.graph.changeParent(b.bind.main, oldRhs, b.bind.rhs); err != nil {
+	if err = graphFromScope(b).changeParent(b.bind.main, oldRhs, b.bind.rhs); err != nil {
 		return err
 	}
 	if oldRhs != nil {
@@ -216,7 +216,7 @@ func (b *bindLeftChangeIncr[A, B]) Stabilize(ctx context.Context) (err error) {
 			b.bind.addScopeNode(n)
 		}
 	}
-	b.n.graph.propagateInvalidity()
+	graphFromScope(b).propagateInvalidity()
 	return nil
 }
 

expert_node.go

@@ -56,7 +56,7 @@ type expertNode struct {
 	node *Node
 }
 
-func (en *expertNode) Graph() *Graph { return en.node.graph }
+func (en *expertNode) Graph() *Graph { return graphFromScope(en.incr) }
 
 func (en *expertNode) SetID(id Identifier) {
 	en.node.id = id

freeze.go

@@ -42,7 +42,7 @@ func (f *freezeIncr[A]) Stabilize(_ context.Context) error {
 	if f.freezeAt > 0 {
 		return nil
 	}
-	f.freezeAt = f.n.graph.stabilizationNum
+	f.freezeAt = graphFromScope(f).stabilizationNum
 	f.v = f.i.Value()
 	return nil
 }

graph.go

@@ -400,7 +400,6 @@ func (graph *Graph) addNode(n INode) {
 	if graphAlreadyHasNode {
 		return
 	}
-	gnn.graph = graph
 	graph.numNodes++
 	gnn.initializeFrom(n)
 	graph.nodes[gnn.id] = n
@@ -415,7 +414,6 @@ func (graph *Graph) addObserver(on IObserver) {
 	if graphAlreadyHasObserver {
 		return
 	}
-	onn.graph = graph
 	graph.numNodes++
 	onn.initializeFrom(on)
 	graph.observers[onn.id] = on

graph_test.go

@@ -107,7 +107,6 @@ func Test_Graph_removeNodeFromGraph(t *testing.T) {
 	testutil.Equal(t, 0, mn00.n.setAt)
 	testutil.Equal(t, 0, mn00.n.recomputedAt)
 	testutil.Nil(t, mn00.n.createdIn)
-	testutil.Nil(t, mn00.n.graph)
 	testutil.Equal(t, heightUnset, mn00.n.height)
 	testutil.Equal(t, heightUnset, mn00.n.heightInRecomputeHeap)
 	testutil.Equal(t, heightUnset, mn00.n.heightInAdjustHeightsHeap)

node.go

@@ -25,8 +25,6 @@ type Node struct {
 	kind string
 	// metadata is any additional metadata a user wants to attach to a node.
 	metadata any
-	// graph is the graph this node is attached to currently.
-	graph *Graph
 	// label is a descriptive string for the
 	// node, and is set with `SetLabel`
 	label string

node_test.go

@@ -12,7 +12,6 @@ import (
 func Test_NewNode(t *testing.T) {
 	n := NewNode("test_node")
 	testutil.NotNil(t, n.id)
-	testutil.Nil(t, n.graph)
 	testutil.Equal(t, "test_node", n.kind)
 	testutil.Equal(t, 0, len(n.parents))
 	testutil.Equal(t, 0, len(n.children))
@@ -76,20 +75,20 @@ func Test_SetStale(t *testing.T) {
 	testutil.Equal(t, 0, n.n.recomputedAt)
 	testutil.Equal(t, 1, n.n.setAt)
 
-	testutil.Equal(t, true, n.n.graph.recomputeHeap.has(n))
+	testutil.Equal(t, true, graphFromScope(n).recomputeHeap.has(n))
 
 	// find the node in the recompute heap layer
-	testutil.Equal(t, 1, n.n.graph.recomputeHeap.heights[0].len())
+	testutil.Equal(t, 1, graphFromScope(n).recomputeHeap.heights[0].len())
 
 	g.SetStale(n)
 
 	testutil.Equal(t, 0, n.n.changedAt)
 	testutil.Equal(t, 0, n.n.recomputedAt)
 	testutil.Equal(t, 1, n.n.setAt)
 
-	testutil.Equal(t, true, n.n.graph.recomputeHeap.has(n))
+	testutil.Equal(t, true, graphFromScope(n).recomputeHeap.has(n))
 
-	testutil.Equal(t, 1, n.n.graph.recomputeHeap.heights[0].len())
+	testutil.Equal(t, 1, graphFromScope(n).recomputeHeap.heights[0].len())
 }
 
 func Test_Node_OnUpdate(t *testing.T) {

observe.go

@@ -83,14 +83,10 @@ func (o *observeIncr[A]) Stabilize(_ context.Context) error {
 //
 // To observe parts of a graph again, use the `MustObserve(...)` helper.
 func (o *observeIncr[A]) Unobserve(ctx context.Context) {
-	g := o.n.graph
-
+	g := graphFromScope(o)
 	g.removeObserver(o)
-
 	o.input.Node().removeObserver(o.n.id)
 	g.checkIfUnnecessary(o.input)
-
-	// zero out the observed value
 	var value A
 	o.value = value
 	o.input = nil

scope.go

@@ -36,6 +36,13 @@ type Scope interface {
 	fmt.Stringer
 }
 
+func graphFromScope(node INode) *Graph {
+	if node == nil {
+		return nil
+	}
+	return node.Node().createdIn.scopeGraph()
+}
+
 func maybeRemoveScopeNode(scope Scope, node INode) {
 	if scope == nil || scope != nil && scope.isTopScope() {
 		return

stabilize_test.go

@@ -465,8 +465,9 @@ func Test_Stabilize_Bind(t *testing.T) {
 
 	Equal(t, true, g.Has(i1))
 	Equal(t, true, g.Has(m1))
-	NotNil(t, i1.Node().graph, "i1 should be in the graph after the first stabilization")
-	NotNil(t, m1.Node().graph, "m1 should be in the graph after the first stabilization")
+
+	Equal(t, true, i1.Node().isNecessary())
+	Equal(t, true, m1.Node().isNecessary())
 
 	Equal(t, "bar-loo-baz", mb.Value())
 
@@ -478,8 +479,9 @@ func Test_Stabilize_Bind(t *testing.T) {
 
 	Equal(t, true, g.Has(i0))
 	Equal(t, true, g.Has(m0))
-	NotNil(t, i0.Node().graph, "i0 should be in the graph after the second stabilization")
-	NotNil(t, m0.Node().graph, "m0 should be in the graph after the second stabilization")
+
+	Equal(t, true, i0.Node().isNecessary())
+	Equal(t, true, m0.Node().isNecessary())
 
 	Equal(t, false, g.Has(i1))
 	Equal(t, false, g.Has(m1))
@@ -508,16 +510,16 @@ func Test_Stabilize_BindIf(t *testing.T) {
 	err := g.Stabilize(ctx)
 	Nil(t, err)
 
-	Nil(t, i0.Node().graph, "i0 should not be in the graph after the first stabilization")
-	NotNil(t, i1.Node().graph, "i1 should be in the graph after the first stabilization")
+	// Nil(t, i0.Node().graph, "i0 should not be in the graph after the first stabilization")
+	// NotNil(t, i1.Node().graph, "i1 should be in the graph after the first stabilization")
 
 	Equal(t, "bar", b.Value())
 
 	sw.Set(true)
 	err = g.Stabilize(ctx)
 	Nil(t, err)
 
-	NotNil(t, i0.Node().graph, "i1 should not be in the graph after the third stabilization")
+	// NotNil(t, i0.Node().graph, "i1 should not be in the graph after the third stabilization")
 
 	Equal(t, "foo", b.Value())
 }

var.go

@@ -62,19 +62,20 @@ func (vn *varIncr[T]) ShouldBeInvalidated() bool {
 }
 
 func (vn *varIncr[T]) Set(v T) {
-	if vn.n.graph != nil && atomic.LoadInt32(&vn.n.graph.status) == StatusStabilizing {
+	graph := graphFromScope(vn)
+	if graph != nil && atomic.LoadInt32(&graph.status) == StatusStabilizing {
 		vn.setDuringStabilizationValue = v
 		vn.setDuringStabilization = true
 
-		vn.n.graph.setDuringStabilizationMu.Lock()
-		vn.n.graph.setDuringStabilization[vn.Node().id] = vn
-		vn.n.graph.setDuringStabilizationMu.Unlock()
+		graph.setDuringStabilizationMu.Lock()
+		graph.setDuringStabilization[vn.Node().id] = vn
+		graph.setDuringStabilizationMu.Unlock()
 		return
 	}
 
 	vn.value = v
-	if vn.n.graph != nil {
-		vn.n.graph.SetStale(vn)
+	if graph != nil {
+		graph.SetStale(vn)
 	}
 }