modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/pass_test.go

@@ -458,6 +458,13 @@ func putOfTheBus(t *testing.T) {
 	if got := step(); got.Step != puts.Released {
 		t.Fatalf("released, the put stands at %s", got.Step)
 	}
+	// A put that stands at an older version than the newest says so (issue 1966): it pins the node's want.
+	okey, _ := puts.Key("g14", "mesh-catalog")
+	older, _ := puts.Encode(puts.Put{FP: meshcatalogclient.SourcePrefix2 + strings.Repeat("b", 64), Why: "old"}.Said(now, puts.Wanted, "wanted"))
+	putsKV.values[okey] = older
+	if l, _ := s.doPuts(map[string]any{"module": "mesh-catalog"}); l.(map[string]any)["puts"].([]putAnswer)[0].Older != fp {
+		t.Errorf("a put older than the newest build says %+v", l)
+	}
 	listed, _ := s.doPuts(map[string]any{"module": "nats"})
 	if l := listed.(map[string]any)["puts"].([]putAnswer); len(l) != 1 || l[0].Step != puts.Released || len(l[0].Steps) < 6 {
 		t.Errorf("puts lists %+v", l)

modules/mesh-delivery-assigner/cmd/mesh-delivery-assigner/tools.go

@@ -130,6 +130,9 @@ type putAnswer struct {
 	Module string `json:"module"`
 	puts.Put
 	Follow string `json:"follow,omitempty"`
+	// Older says a put that has not ended stands at an older version than the newest build, and which that is: it pins the
+	// node's want until it ends or is released.
+	Older string `json:"older-than-newest,omitempty"`
 }
 
 // doPut is the tool assigner_put.
@@ -249,6 +252,8 @@ func (s *putTools) doPuts(args map[string]any) (any, error) {
 	}
 	sort.Strings(keys)
 	out := []putAnswer{}
+	newest := map[string]string{} // the indexer's newest fingerprint by module, asked once and only for a put that stands
+	asked := false
 	for _, key := range keys {
 		node, module, err := puts.ParseKey(key)
 		if err != nil || (arg(args, "node") != "" && node != arg(args, "node")) || (arg(args, "module") != "" && module != arg(args, "module")) {
@@ -262,7 +267,23 @@ func (s *putTools) doPuts(args map[string]any) (any, error) {
 		if err != nil {
 			continue
 		}
-		out = append(out, putAnswer{Node: node, Module: module, Put: p})
+		a := putAnswer{Node: node, Module: module, Put: p}
+		if !puts.Ended(p.Step) {
+			if !asked {
+				asked = true
+				if mods, err := indexerView(s.ask, indexerModules); err == nil {
+					for name, raw := range mods {
+						if m, err := meshcatalogclient.DecodeModule(raw); err == nil {
+							newest[name] = m.Fp2
+						}
+					}
+				}
+			}
+			if n := newest[module]; n != "" && n != p.FP {
+				a.Older = n
+			}
+		}
+		out = append(out, a)
 	}
 	return map[string]any{"puts": out}, nil
 }

modules/mesh-delivery-assigner/internal/assign/put.go

@@ -157,7 +157,15 @@ func StepPut(w PutWorld) PutNext {
 // applied is a wanted put once the node's have says how it went: holding or done when it runs the composition healthy.
 func applied(w PutWorld, p puts.Put) puts.Put {
 	h := w.Have
-	if h == nil || h.Fp != p.FP || h.Composed != p.Composed {
+	if h == nil || h.Fp != p.FP {
+		return p
+	}
+	// A put without a hold ends on the fingerprint alone: a node that composes its own digests no composition of the put's, and
+	// a put that waits for that one pins the module's want for good (issue 1966). A held put keeps its composition.
+	if !p.Hold && h.Phase == nodeengineclient.PhaseRunning && h.Health == nodeengineclient.HealthOK {
+		return p.Said(w.Now, puts.Done, fmt.Sprintf("%s runs %s at %s healthy; the rules write its want again", w.Node, w.Module, short(p.FP)))
+	}
+	if h.Composed != p.Composed {
 		return p
 	}
 	switch {

modules/mesh-delivery-assigner/internal/assign/wants_test.go

@@ -933,6 +933,21 @@ func stepsOfAPut(t *testing.T) {
 			w.Have = &nodeengine.HaveByNodeModuleValue{Fp: fNew, Composed: d.Digest, Phase: nodeengineclient.PhaseRunning, Health: nodeengineclient.HealthOK}
 			return w
 		}, puts.Done, "the rules write its want again", false, false, false},
+		{"wanted without hold, the node composes its own: done at the fingerprint", func() PutWorld {
+			w := bus()
+			w.Put.Hold = false
+			w.Put = w.Put.Said(now, puts.Wanted, "wanted")
+			w.Put.Composed = d.Digest
+			w.Have = &nodeengine.HaveByNodeModuleValue{Fp: fNew, Composed: dig(fOld), Phase: nodeengineclient.PhaseRunning, Health: nodeengineclient.HealthOK}
+			return w
+		}, puts.Done, "the rules write its want again", false, false, false},
+		{"wanted with hold, the node composes its own: stays wanted", func() PutWorld {
+			w := bus()
+			w.Put = w.Put.Said(now, puts.Wanted, "wanted")
+			w.Put.Composed = d.Digest
+			w.Have = &nodeengine.HaveByNodeModuleValue{Fp: fNew, Composed: dig(fOld), Phase: nodeengineclient.PhaseRunning, Health: nodeengineclient.HealthOK}
+			return w
+		}, puts.Wanted, "wanted", false, false, false},
 		{"released: nothing more", func() PutWorld { w := bus(); w.Put = w.Put.Said(now, puts.Released, "released"); return w }, puts.Released, "released", false, false, false},
 	}
 	for _, c := range cases {