From dec3b83e66b4e591b51e4cbdff523addfeb1344f Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Fri, 23 Oct 2026 16:11:07 +0200
Subject: [PATCH] Test that the builder, a build module and the controller are
 taken from the builder's keys and nothing reaches node-build-agent (issue
 1851, C2 criterion)

---
 .../walk_from_keys_integration_test.go        | 53 +++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/cmd/mesh-controller/walk_from_keys_integration_test.go b/cmd/mesh-controller/walk_from_keys_integration_test.go
index bc8960c1..3705da9d 100644
--- a/cmd/mesh-controller/walk_from_keys_integration_test.go
+++ b/cmd/mesh-controller/walk_from_keys_integration_test.go
@@ -3,6 +3,7 @@
 package main
 
 import (
+	"github.com/nats-io/nats.go"
 	"reflect"
 	"strings"
 	"testing"
@@ -102,3 +103,55 @@ func TestAFailedKeyFailsTheWalkInTheBuildersWords(t *testing.T) {
 		t.Fatalf("A7: a failed walk sent %v", tm.sent)
 	}
 }
+
+// C2's criterion (issue 1851, R4g): a merge whose walk moves the builder, a build module and the controller takes every one
+// from the builder's referenced done key, and no ask reaches any subject of the seat node-build-agent. A fake builder writes
+// the keys on a real bus.
+func TestTheBuilderABuildModuleAndTheControllerAreTakenFromKeysAndNothingIsAskedOfBuildAgent(t *testing.T) {
+	names := []string{sdkdelivery.BuilderModule, "mesh-build-go", "mesh-controller"}
+	tm := aTierMesh(t, names...)
+	ctx := t.Context()
+	inv := tm.open.inventory
+	b := aBuilderOnTheBus(t)
+	asked := make(chan string, 16)
+	sub, err := b.js.Conn().Subscribe("mesh.seat.node-build-agent.>", func(m *nats.Msg) { asked <- m.Subject })
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = sub.Unsubscribe() })
+
+	p := tm.plan(t)
+	p.Commit = "c5c5c5c5c5c5c5c5"
+	for _, m := range names {
+		p.Modules[m] = &inventory.PlanModule{}
+	}
+	if err := inv.SavePlan(ctx, &p); err != nil {
+		t.Fatal(err)
+	}
+	for i, m := range names {
+		fp := fpOf(byte('a' + i))
+		manifest := b.indexed(t, m, "c5", "novox/mesh-catalog", "modules/"+m, p.Commit, fp)
+		b.built(t, m, "c5", fp, manifest, sdkdelivery.BuildDone)
+	}
+	becomes(t, 10*time.Second, "the three taken from their keys", func() bool {
+		advancePlans(ctx, tm.open)
+		q := tm.plan(t)
+		for _, m := range names {
+			if s := q.Modules[m]; s == nil || s.State != "built" {
+				return false
+			}
+		}
+		return true
+	})
+	p = tm.plan(t)
+	for _, m := range names {
+		if s := p.Modules[m]; !s.Key || !strings.HasPrefix(s.Build, "key-") || !strings.Contains(s.Made, "taken from the builder's key") {
+			t.Errorf("%s was not taken from the builder's referenced key: %+v", m, s)
+		}
+	}
+	select {
+	case subject := <-asked:
+		t.Fatalf("an ask reached the retired build seat: %s", subject)
+	case <-time.After(300 * time.Millisecond):
+	}
+}