Settle candidates only through verified atomic binding-plus-receipt commits

.github/reviews/trusted-settlement.receipt.json

@@ -0,0 +1,4 @@
+{
+  "reviewed_tree": "a76b668137a154fe54cbf0d3cf5398ebda7387ff",
+  "program_fingerprint": "3ca3397ff275d89bdb6d5c934b86b51d3cbdfab0ee628c47fe94d1d4f5767155"
+}

boatstack/kernel/conformance/conformance.go

@@ -114,7 +114,10 @@ func (suite KernelConformance) objectiveBinding(t *testing.T) {
 	if after.State.ObjectiveBinding == nil || !after.State.ObjectiveBinding.Matches(fixture.Scenario.Objective) {
 		t.Fatal("control-law objective-binding: apply did not bind the exact objective")
 	}
-	if after.CommitCount != before.CommitCount+1 || len(after.Receipts) != len(before.Receipts)+1 || receipt.ObjectiveBinding == nil {
+	if after.CommitCount != before.CommitCount+1 || len(after.Receipts) != len(before.Receipts)+1 ||
+		receipt.PriorObjectiveBinding != nil ||
+		receipt.RequestedObjectiveBinding == nil || !receipt.RequestedObjectiveBinding.Matches(fixture.Scenario.Objective) ||
+		receipt.ResultObjectiveBinding == nil || !receipt.ResultObjectiveBinding.Matches(fixture.Scenario.Objective) {
 		t.Fatalf("control-law objective-binding: commit/receipt evidence is incomplete: %#v", after)
 	}
 }
@@ -127,6 +130,10 @@ func (suite KernelConformance) objectiveAbsence(t *testing.T) {
 	if before.State.ObjectiveBinding != nil || after.State.ObjectiveBinding != nil {
 		t.Fatal("control-law objective-absence: maintenance synthesized an objective binding")
 	}
+	receipt := after.Receipts[len(after.Receipts)-1]
+	if receipt.PriorObjectiveBinding != nil || receipt.RequestedObjectiveBinding != nil || receipt.ResultObjectiveBinding != nil {
+		t.Fatalf("control-law objective-absence: maintenance receipt synthesized objective lineage: %#v", receipt)
+	}
 }
 
 func (suite KernelConformance) maintenancePreservesExactBinding(t *testing.T) {
@@ -137,6 +144,12 @@ func (suite KernelConformance) maintenancePreservesExactBinding(t *testing.T) {
 	if before.State.ObjectiveBinding == nil || after.State.ObjectiveBinding == nil || *after.State.ObjectiveBinding != *before.State.ObjectiveBinding {
 		t.Fatal("control-law objective-preservation: maintenance changed the exact binding")
 	}
+	receipt := after.Receipts[len(after.Receipts)-1]
+	if !reflect.DeepEqual(receipt.PriorObjectiveBinding, before.State.ObjectiveBinding) ||
+		receipt.RequestedObjectiveBinding != nil ||
+		!reflect.DeepEqual(receipt.ResultObjectiveBinding, after.State.ObjectiveBinding) {
+		t.Fatalf("control-law objective-preservation: receipt lineage differs from preserved binding: %#v", receipt)
+	}
 }
 
 func (suite KernelConformance) objectiveRevisionInvalidatesPrescription(t *testing.T) {
@@ -811,7 +824,12 @@ func committedOutcomeError(program kernel.Program, scenario Scenario, before, af
 	if !ok {
 		return fmt.Errorf("returned receipt transition is absent from program")
 	}
-	if after.State.InstanceID != returned.InstanceID || after.State.Program != returned.Program || after.State.Revision != returned.ResultStateRevision || after.State.Mode != transition.TargetMode || after.State.Recovery != nil || !reflect.DeepEqual(after.State.ObjectiveBinding, returned.ObjectiveBinding) {
+	if !reflect.DeepEqual(returned.PriorObjectiveBinding, before.State.ObjectiveBinding) ||
+		!reflect.DeepEqual(returned.RequestedObjectiveBinding, prescription.RequestedObjectiveBinding) ||
+		!reflect.DeepEqual(returned.ResultObjectiveBinding, after.State.ObjectiveBinding) {
+		return fmt.Errorf("receipt objective lineage differs from prior, requested, or resulting state")
+	}
+	if after.State.InstanceID != returned.InstanceID || after.State.Program != returned.Program || after.State.Revision != returned.ResultStateRevision || after.State.Mode != transition.TargetMode || after.State.Recovery != nil {
 		return fmt.Errorf("durable state differs from winning receipt outcome")
 	}
 	if err := exactEffectDelta(before.Effects, after.Effects, returned.TransitionID, 1); err != nil {

boatstack/kernel/conformance/conformance_test.go

@@ -229,6 +229,49 @@ func TestCommittedOutcomeRejectsFalsePriorObservation(t *testing.T) {
 	}
 }
 
+func TestCommittedOutcomeRejectsObjectiveLineageSubstitution(t *testing.T) {
+	for name, mutate := range map[string]func(*kernel.Receipt, *kernel.ObjectiveBinding){
+		"prior": func(receipt *kernel.Receipt, other *kernel.ObjectiveBinding) {
+			receipt.PriorObjectiveBinding = other
+		},
+		"requested": func(receipt *kernel.Receipt, other *kernel.ObjectiveBinding) {
+			receipt.RequestedObjectiveBinding = other
+		},
+		"result": func(receipt *kernel.Receipt, other *kernel.ObjectiveBinding) {
+			receipt.ResultObjectiveBinding = other
+		},
+	} {
+		t.Run(name, func(t *testing.T) {
+			fixture := newIntegerFixture(SetupUnbound)
+			runtime := mustRuntime(t, fixture)
+			request, prescription := resolve(t, runtime, fixture.Scenario, fixture.Scenario.BindTransition, &fixture.Scenario.Objective, fixture.Scenario.Authority)
+			before := fixture.Scenario.Snapshot()
+			returned, err := runtime.Apply(context.Background(), kernel.ApplyRequest{ResolveRequest: request, Prescription: prescription})
+			if err != nil {
+				t.Fatal(err)
+			}
+			other, err := kernel.BindObjective(fixture.Scenario.ConflictingObjective)
+			if err != nil {
+				t.Fatal(err)
+			}
+			mutate(&returned, &other)
+			returned.ID = ""
+			digest, err := kernel.Fingerprint(returned)
+			if err != nil {
+				t.Fatal(err)
+			}
+			returned.ID = "rcp-" + digest
+			receipts := fixture.Store.(*MemoryStateStore).receipts
+			receipts.mu.Lock()
+			receipts.values[len(receipts.values)-1] = returned
+			receipts.mu.Unlock()
+			if err := committedOutcomeError(fixture.Program, fixture.Scenario, before, fixture.Scenario.Snapshot(), prescription, returned); err == nil {
+				t.Fatalf("content-rehashed %s objective lineage substitution was accepted", name)
+			}
+		})
+	}
+}
+
 func TestCommittedOutcomeRejectsNoOpAcceptedByDomainVerifier(t *testing.T) {
 	fixture := newIntegerFixture(SetupBound)
 	domain := fixture.Domain.(*IntegerDomain)