mesh-wants upgrade reads through mesh-sdk's watched reader, keeping no mirror of its own

One helper serves every part that reads whole states (ADR 0580 clause 3): the assigner's own watched mirror goes, its
compare reads the large states from stdio.WatchedStates and each manifest once per digest. mesh-sdk pinned at 8311ecb.

Claude-Session: https://claude.ai/code/session_01NcbgfJ9Gum47zkFKWRaovL

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

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"reflect"
 	"slices"
 	"strings"
 	"testing"
@@ -15,6 +16,7 @@ import (
 	"git.novox.be/novox/mesh-sdk/go/buscompose"
 	"git.novox.be/novox/mesh-sdk/go/catalogue"
 	"git.novox.be/novox/mesh-sdk/go/delivery"
+	"git.novox.be/novox/mesh-sdk/go/health"
 	"git.novox.be/novox/mesh-sdk/go/provisions"
 	"github.com/nats-io/nats.go/jetstream"
 
@@ -400,6 +402,47 @@ func wantsVerbs(t *testing.T) {
 	if splits := out.(map[string]any)["splits"].([]assign.Split); len(splits) != 1 || splits[0].Module != "web" || out.(map[string]any)["findings"] == nil {
 		t.Errorf("splits = %+v", splits)
 	}
+	// Read by watch (issue 1953 L5f): the same answer, each watched state started once, and no get per key of the
+	// large states (the modules, their manifests, the composed record).
+	watches := map[string]int{}
+	byWatch := newWantsTools(st, nil, nil)
+	byWatch.watched = stdio.WatchedStatesOver(func(state string, handle func(stdio.StateChange) error) error {
+		watches[state]++
+		for k, v := range st[state].values {
+			_ = handle(stdio.StateChange{Key: k, Op: stdio.OpPut, Value: v, Current: true})
+		}
+		return nil
+	}, func(state, key string) ([]byte, bool, error) {
+		watches[state+" by key"]++
+		v, ok := st[state].values[key]
+		return v, ok, nil
+	})
+	for range 2 {
+		wout, werr := byWatch.doUpgrade(map[string]any{"compare": "true"}, "op")
+		if werr != nil {
+			t.Fatal(werr)
+		}
+		if ws := wout.(map[string]any)["splits"].([]assign.Split); len(ws) != 1 || ws[0].Module != "web" {
+			t.Errorf("splits by watch = %+v", ws)
+		}
+	}
+	if n := watches[manifestsState+" by key"]; n == 0 || n > len(st[manifestsState].values) {
+		t.Errorf("the manifests were read by key %d times, want each once", n)
+	}
+	for _, state := range []string{modulesState, composedState, health.FindingsState} {
+		if watches[state] != 1 {
+			t.Errorf("%s was watched %d times, want once", state, watches[state])
+		}
+	}
+	// ADR 0580 clause 3: the compare reads through mesh-sdk's watched reader and the seat keeps no mirror of its own.
+	for f := range reflect.TypeFor[wantsTools]().Fields() {
+		if f.Type.Kind() == reflect.Map || (f.Type.Kind() == reflect.Pointer && f.Type.Elem().Kind() == reflect.Map) {
+			t.Errorf("wantsTools keeps %s, a copy of its own beside the watched reader", f.Name)
+		}
+	}
+	if watches[policiesState] != 0 {
+		t.Errorf("the seat's own small policies state was watched: %v", watches)
+	}
 	// The process says the split as its finding, and deletes it once they agree.
 	findings := map[string][]byte{}
 	p := &passer{w: newWorld(), logf: func(string, ...any) {}, findings: assign.Findings{

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

@@ -352,10 +352,12 @@ func serveTools() error {
 		}
 	}()
 	tools := append(s.tools(), newSeatTools(runtimeStore{}, stdio.Ask).tools()...)
-	tools = append(tools, newWantsTools(runtimeStore{}, stdio.Ask, func(e, id string, b any) error {
+	wants := newWantsTools(runtimeStore{}, stdio.Ask, func(e, id string, b any) error {
 		// The seat's event, said on the seat: a claimed seat's event is never the module's own.
 		return stdio.SeatPublish(wantsEventSubject(e), b, id)
-	}).tools()...)
+	})
+	wants.watched = stdio.NewWatchedStates() // the large states read whole from one watched copy (ADR 0580 clause 3)
+	tools = append(tools, wants.tools()...)
 	return stdio.Serve("", tools)
 }
 

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

@@ -41,6 +41,10 @@ type wantsTools struct {
 	ask  func(key string, body any) (json.RawMessage, error)
 	emit func(event, id string, body any) error
 	now  func() time.Time
+	// watched is the copy of the large states it reads whole, each by one watch started on its first read and kept by
+	// its changes after (mesh-sdk's WatchedStates, novox/hq ADR 0580 clause 3), never a get per key, which timed out on
+	// a large state (issue 1953 L5f). Nil reads key by key.
+	watched *stdio.WatchedStates
 }
 
 // wantsEventSubject is the subject of one of the seat's events.
@@ -59,8 +63,16 @@ func (s *wantsTools) leased() bool {
 	return away
 }
 
-// values reads every key of a state.
+// values reads every key of a state: from the watched copy when there is one, else key by key.
 func (s *wantsTools) values(state string) (map[string][]byte, error) {
+	if s.watched != nil {
+		return s.watched.Values(state)
+	}
+	return s.direct(state)
+}
+
+// direct reads a state key by key, for a small state of the seat's own.
+func (s *wantsTools) direct(state string) (map[string][]byte, error) {
 	keys, err := s.st.keys(state)
 	if err != nil {
 		return nil, fmt.Errorf("%s cannot be listed: %w", state, err)
@@ -78,6 +90,16 @@ func (s *wantsTools) values(state string) (map[string][]byte, error) {
 	return out, nil
 }
 
+// manifest reads a manifest by its digest: kept once read when there is a watched copy, a manifest never changing
+// under its digest.
+func (s *wantsTools) manifest(digest string) ([]byte, bool, error) {
+	if s.watched != nil {
+		return s.watched.Once(manifestsState, digest)
+	}
+	raw, _, found, err := s.st.get(manifestsState, digest)
+	return raw, found, err
+}
+
 // manifests is every module the indexer holds, with its trunk manifest and fingerprint.
 func (s *wantsTools) manifests() (map[string]catalogue.Manifest, map[string]delivery.Module, error) {
 	mods, err := s.values(modulesState)
@@ -94,7 +116,7 @@ func (s *wantsTools) manifests() (map[string]catalogue.Manifest, map[string]deli
 		if m.Manifest == "" {
 			continue
 		}
-		mraw, _, found, err := s.st.get(manifestsState, m.Manifest)
+		mraw, found, err := s.manifest(m.Manifest)
 		if err != nil || !found {
 			continue
 		}
@@ -126,7 +148,7 @@ func (s *wantsTools) doUpgrade(args map[string]any, by string) (any, error) {
 	if err != nil {
 		return nil, err
 	}
-	raw, err := s.values(policiesState)
+	raw, err := s.direct(policiesState) // the seat's own small state, read whole after its own writes
 	if err != nil {
 		return nil, err
 	}

modules/mesh-delivery-assigner/go.mod

@@ -3,7 +3,7 @@ module mesh-delivery-assigner
 go 1.26.0
 
 require (
-	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261101020750-62cddf4efc62
+	git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261101023317-8311ecb84911
 	github.com/nats-io/nats-server/v2 v2.11.17
 	github.com/nats-io/nats.go v1.54.0
 )

modules/mesh-delivery-assigner/go.sum

@@ -12,6 +12,10 @@ git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261101014310-19c204273bdc h1:kVq7sS4I
 git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261101014310-19c204273bdc/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
 git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261101020750-62cddf4efc62 h1:R5C8ICjiaDITHRFR/uIATwARPPXKxssUC70m0svstb0=
 git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261101020750-62cddf4efc62/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261101022905-ba8b8f28a364 h1:UUDPWfUjyerptar+wPwI891jTUAtbbuXori0j3phTE4=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261101022905-ba8b8f28a364/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261101023317-8311ecb84911 h1:+82ygf2hiY5Mhwfmc1xfCe9e/KY/5ObBuE2LecM37qI=
+git.novox.be/novox/mesh-sdk/go v0.1.14-0.20261101023317-8311ecb84911/go.mod h1:ouERNpZizzwZ0HLEtAypsY9FR20FyUgUYRni6J7kVCY=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op h1:Z/MZK75wC/NSrkgqeNIa7jexam9uWzhLmFTSCPI/kn0=
 github.com/antithesishq/antithesis-sdk-go v0.7.0-default-no-op/go.mod h1:FQyySiasQQM8735Ddel3MRojmy4dA1IqCeyJ5jmPMbI=
 github.com/google/go-tpm v0.9.8 h1:slArAR9Ft+1ybZu0lBwpSmpwhRXaa85hWtMinMyRAWo=