From e14b02991e8052649486ec2997029d72a589c1e0 Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Sat, 26 Sep 2026 23:40:04 +0200
Subject: [PATCH] The controller marks a deliberately-empty declaration
 owns_nothing (hq 127)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The host refuses an empty body unless told the emptiness is meant
(mesh-host#29). When a node's declaration composes to no resources —
which #77 now sends rather than skips — Body() sets owns_nothing, so
the node applies it and drops what it last held. A declaration with
resources never carries the marker. One test.
---
 cmd/mesh-controller/sendable.go      |  6 ++++++
 cmd/mesh-controller/sendable_test.go | 22 ++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/cmd/mesh-controller/sendable.go b/cmd/mesh-controller/sendable.go
index 8c282ac..fdebf7e 100644
--- a/cmd/mesh-controller/sendable.go
+++ b/cmd/mesh-controller/sendable.go
@@ -38,6 +38,12 @@ func (s sendable) Body() ([]byte, error) {
 	if s.Adoption != nil {
 		envelope["adoption"] = s.Adoption
 	}
+	// An empty declaration is deliberate here — the node owns nothing the mesh put there
+	// (novox/hq issue 127) — and the host refuses an empty body unless it is told the emptiness
+	// is meant, so a truncated or mis-composed body is never mistaken for "own nothing".
+	if len(s.Resources) == 0 {
+		envelope["owns_nothing"] = true
+	}
 	return json.Marshal(envelope)
 }
 
diff --git a/cmd/mesh-controller/sendable_test.go b/cmd/mesh-controller/sendable_test.go
index f831e34..73ce86c 100644
--- a/cmd/mesh-controller/sendable_test.go
+++ b/cmd/mesh-controller/sendable_test.go
@@ -355,3 +355,25 @@ func TestTheMachineSideOfAMappingIsMovedEverywhereTheNumberIsUsed(t *testing.T)
 		t.Fatalf("the consumer is told the forge answers on %v", told)
 	}
 }
+
+func TestAnEmptyDeclarationSaysOwnsNothing(t *testing.T) {
+	// The host refuses an empty body unless told the emptiness is meant (novox/hq issue 127).
+	body, err := sendable{}.Body()
+	if err != nil {
+		t.Fatal(err)
+	}
+	var env map[string]any
+	if err := json.Unmarshal(body, &env); err != nil {
+		t.Fatal(err)
+	}
+	if env["owns_nothing"] != true {
+		t.Fatalf("an empty declaration must mark owns_nothing; got %v", env)
+	}
+	// A declaration with resources does not carry the marker.
+	body, _ = sendable{Resources: []map[string]any{{"id": "x"}}}.Body()
+	var env2 map[string]any
+	_ = json.Unmarshal(body, &env2)
+	if _, present := env2["owns_nothing"]; present {
+		t.Fatalf("a non-empty declaration must not mark owns_nothing; got %v", env)
+	}
+}