Keep a walk's withheld modules on its record, name every machine a stopped send reached, and list the stop's store tests (review of #232)

cmd/mesh-controller/batches.go

@@ -768,6 +768,7 @@ func planBatch(ctx context.Context, open *stores, batch *inventory.Plan, carry [
 	}
 	sort.Strings(also)
 	ordered := groupOrderEdges(members, entries, read, edges)
+	var withheld []string
 	plan := planOfMoves(moved, append(append([]inventory.Edge{}, edges...), ordered...))
 	// **Withheld, a stopped merge's modules** (novox/hq ADR 0299): a module is built at its branch, which holds the
 	// merge a stop left out of the walk these merges were walked again from — built here only as a dependent, it
@@ -775,6 +776,7 @@ func planBatch(ctx context.Context, open *stores, batch *inventory.Plan, carry [
 	// and the stop named it.
 	if batch.Delivery != nil && batch.Delivery.Batch != nil {
 		if out := withhold(&plan, batch.Delivery.Batch.Withheld, moved); len(out) > 0 {
+			withheld = out
 			fmt.Printf("  withheld, a stopped merge's modules built only as dependents: %s\n", strings.Join(out, ", "))
 		}
 	}
@@ -788,6 +790,7 @@ func planBatch(ctx context.Context, open *stores, batch *inventory.Plan, carry [
 	}
 	plan.Delivery.Merges = named
 	plan.Delivery.Alone = batch.Delivery != nil && batch.Delivery.Alone
+	plan.Delivery.Withheld = withheld
 	// **Its moments and its class** (novox/hq ADR 0282 decision 6): measured, never acted on.
 	plan.Times = walkTimesAtCut(*batch, plan, entries, now)
 	if len(moved) == 0 {

cmd/mesh-controller/delivery.go

@@ -191,7 +191,15 @@ func stopWalkWithout(ctx context.Context, inv *inventory.Inventory, id, by, why
 	if batch {
 		return p, said, stopInBatch(ctx, inv, &p, merges, again, &said, stopped, now)
 	}
-	said.Kept = keptOf(p, movesOf(again))
+	entries, err := inv.Catalogued(ctx)
+	if err != nil {
+		return p, said, err
+	}
+	running := map[string][]string{}
+	for _, e := range entries {
+		running[e.Manifest.Module] = e.On
+	}
+	said.Kept = keptOf(p, movesOf(again), running)
 	stopped(&p)
 	p.Delivery.Kept = said.Kept
 	if len(again) == 0 {
@@ -413,8 +421,10 @@ func movesOf(merges []inventory.BatchedMerge) []string {
 }
 
 // keptOf are the modules a stopped walk sent that no merge walked again moves, and the machines each reached:
-// those keep running the stopped walk's build.
-func keptOf(p inventory.Plan, walkedAgain []string) []inventory.PlanKept {
+// those keep running the stopped walk's build. A module sent to its first machines reached those, and the rest it
+// was sent to after them; one sent with no first machine (its policy sends it to all together, or a later tier is
+// built by it) reached every machine running it.
+func keptOf(p inventory.Plan, walkedAgain []string, running map[string][]string) []inventory.PlanKept {
 	var out []inventory.PlanKept
 	for name, m := range p.Modules {
 		if m == nil || slices.Contains(walkedAgain, name) {
@@ -424,6 +434,9 @@ func keptOf(p inventory.Plan, walkedAgain []string) []inventory.PlanKept {
 		if m.FirstAt != nil || m.SentAt != nil {
 			machines = union(machines, m.First)
 		}
+		if m.SentAt != nil && len(m.First) == 0 {
+			machines = union(machines, running[name])
+		}
 		if m.Gate != nil && m.Gate.Since != nil {
 			machines = union(machines, m.Gate.Machines)
 		}

cmd/mesh-controller/issue459_test.go

@@ -391,3 +391,22 @@ func TestSavingPlansAndMovingMergesIsOneAct(t *testing.T) {
 		t.Fatalf("the merge moved to %q though the act was refused", m.Plan)
 	}
 }
+
+// What a stopped walk leaves on the machines names every machine its sends reached (review of #232): a module sent
+// with no first machine reached every machine running it; one sent first reached those, and the rest it was sent
+// to; a module a merge walked again moves is sent again, and is not named.
+func TestKeptNamesEveryMachineASendReached(t *testing.T) {
+	at := t0
+	p := inventory.Plan{Modules: map[string]*inventory.PlanModule{
+		"together": {SentAt: &at},
+		"first":    {First: []string{"anchor"}, FirstAt: &at, Rest: map[string]inventory.SentDeclaration{"laptop": {}}},
+		"again":    {SentAt: &at},
+		"unsent":   {},
+	}}
+	got := keptOf(p, []string{"again"}, map[string][]string{"together": {"laptop", "anchor"}, "again": {"anchor"}})
+	want := []inventory.PlanKept{{Module: "first", Machines: []string{"anchor", "laptop"}},
+		{Module: "together", Machines: []string{"anchor", "laptop"}}}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("kept %+v; want %+v", got, want)
+	}
+}