Review round 1 of the bus want: a removal keeps the bus server, the have says a server made anew runs the want's fingerprint, the old build is read before the first write, and an unanswered inspect fails the apply rather than replacing the server (ADR 0594 §2, §4)

cmd/mesh-host/nodeagent.go

@@ -123,8 +123,8 @@ func (h sessionHaves) Write(ctx context.Context, x agent.Have) {
 		Sealed: x.Sealed, Server: x.Server})
 }
 
-func (h sessionHaves) Removed(ctx context.Context, module string) {
-	h.session.NoteRemoved(ctx, module, "")
+func (h sessionHaves) Removed(ctx context.Context, module string, words ...string) {
+	h.session.NoteRemoved(ctx, module, "", words...)
 }
 
 // shorten keeps a have's detail within what a have value holds: its head, which says what failed, and its tail, which is
@@ -564,9 +564,9 @@ func nodeAgent(ctx context.Context, opts options, signer ed25519.PublicKey, trus
 				sayFacts(ctx, ag)
 				return res
 			},
-			Remove: func(ctx context.Context, module string, others []delivery.Composed) agent.Result {
+			Remove: func(ctx context.Context, module string, others []delivery.Composed, keep map[string]bool) agent.Result {
 				actx, done := applyContext(session.WithLink(ctx))
-				res := removeComposition(actx, opts, module, others, ag.Placed(module), sched, say)
+				res := removeComposition(actx, opts, module, others, ag.Placed(module), keep, sched, say)
 				done()
 				afterApply()
 				sayFacts(ctx, ag)
@@ -732,13 +732,13 @@ func applyComposition(ctx context.Context, opts options, c delivery.Composed, ot
 	if got.Probe != nil {
 		return failedWith(got.Probe.partial().Error())
 	}
-	return agent.Result{}
+	return agent.Result{Kept: got.Outcome.Kept}
 }
 
 // removeComposition removes one module's own resources and nothing of another's.
-func removeComposition(ctx context.Context, opts options, module string, others []delivery.Composed, placed map[string]bool,
+func removeComposition(ctx context.Context, opts options, module string, others []delivery.Composed, placed, keep map[string]bool,
 	sched *apply.Scheduler, say link.Announce) agent.Result {
-	scope := apply.Scope{Module: module, Others: resourcesOf(others), Placed: placed}
+	scope := apply.Scope{Module: module, Others: resourcesOf(others), Placed: placed, Keep: keep}
 	got := applyModuleHeld(ctx, opts, &declaration.Declaration{Version: declaration.Version}, &scope, sched, say)
 	switch {
 	case got.Refused != "":
@@ -746,7 +746,7 @@ func removeComposition(ctx context.Context, opts options, module string, others
 	case got.Err != nil:
 		return agent.Result{Failed: true, Detail: shorten(got.Err.Error())}
 	}
-	return agent.Result{}
+	return agent.Result{Kept: got.Outcome.Kept}
 }
 
 // busyModules are the modules whose last apply left a container running because it said busy.