Migrate NPC registry to shared resolver

internal/modules/dnd/npcs/registry/registry.go

@@ -7,9 +7,6 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
-	"mime"
-	"strings"
-	"sync"
 
 	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
 	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
@@ -17,6 +14,7 @@ import (
 	npccodec "gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/codec/npcs"
 	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/npcs/identity"
 	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/shared/diagnostics"
+	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/shared/registryresolver"
 )
 
 const (
@@ -37,39 +35,20 @@ type Registry struct {
 	lookupByKey      map[string]int
 }
 
-// Resolver retains only the validated construction-time registry and immutable
-// canonical registries keyed by their semantic digest. Operation references
-// are resolved on demand; caller-owned reference bytes are never retained.
+// Resolver selects and memoizes immutable NPC registry views.
 type Resolver struct {
-	seeded *Registry
-
-	mu       sync.Mutex
-	cache    map[string]*Registry
-	rawCache map[string]*Registry
+	resolver *registryresolver.Resolver[*Registry]
 }
 
 // NewResolver validates the optional construction-time NPC reference and
 // prepares the operation-time registry cache. A malformed static reference
 // therefore fails before any operation starts.
 func NewResolver(references contracts.ReferenceSet) (*Resolver, error) {
-	seeded, err := Resolve(constructionReferences(references))
+	resolver, err := registryresolver.New(registryResolverConfig(), references)
 	if err != nil {
 		return nil, err
 	}
-	return &Resolver{seeded: seeded, cache: make(map[string]*Registry), rawCache: make(map[string]*Registry)}, nil
-}
-
-func constructionReferences(references contracts.ReferenceSet) contracts.ReferenceSet {
-	slot, ok := references.Slots[ReferenceSlot]
-	if !ok || len(slot.Items) > 0 {
-		return references
-	}
-	cloned := contracts.ReferenceSet{Slots: make(map[string]contracts.ResolvedReferenceSlot, len(references.Slots))}
-	for name, value := range references.Slots {
-		cloned.Slots[name] = value
-	}
-	delete(cloned.Slots, ReferenceSlot)
-	return cloned
+	return &Resolver{resolver: resolver}, nil
 }
 
 // Seeded returns the immutable construction-time registry. Its accessors are
@@ -78,7 +57,7 @@ func (r *Resolver) Seeded() *Registry {
 	if r == nil {
 		return nil
 	}
-	return r.seeded
+	return r.resolver.Seeded()
 }
 
 // Resolve returns the effective registry for one operation. An operation
@@ -86,90 +65,57 @@ func (r *Resolver) Seeded() *Registry {
 // matching that registry reuses it; other canonical registries are cached by
 // digest for concurrent chunk operations.
 func (r *Resolver) Resolve(references contracts.ReferenceSet) (*Registry, error) {
-	if r == nil {
+	if r == nil || r.resolver == nil {
 		return Resolve(references)
 	}
-	if _, ok := references.Slots[ReferenceSlot]; !ok {
-		return r.seeded, nil
-	}
-
-	slot := references.Slots[ReferenceSlot]
-	rawKey := ""
-	if len(slot.Items) == 1 {
-		rawKey = strings.ToLower(strings.TrimSpace(slot.Items[0].MediaType)) + "\x00" + semanticDigest(slot.Items[0].Content)
-	}
-
-	r.mu.Lock()
-	defer r.mu.Unlock()
-	if rawKey != "" {
-		if cached, ok := r.rawCache[rawKey]; ok {
-			return cached, nil
-		}
-	}
-	resolved, err := Resolve(references)
-	if err != nil {
-		return nil, err
-	}
-	if sameRegistryIdentity(r.seeded, resolved) {
-		if rawKey != "" {
-			r.rawCache[rawKey] = r.seeded
-		}
-		return r.seeded, nil
-	}
-
-	if cached, ok := r.cache[resolved.Digest()]; ok {
-		if rawKey != "" {
-			r.rawCache[rawKey] = cached
-		}
-		return cached, nil
-	}
-	r.cache[resolved.Digest()] = resolved
-	if rawKey != "" {
-		r.rawCache[rawKey] = resolved
-	}
-	return resolved, nil
-}
-
-func sameRegistryIdentity(first, second *Registry) bool {
-	if first == nil || second == nil {
-		return first == second
-	}
-	return first.bound == second.bound && first.digest == second.digest
+	return r.resolver.Resolve(references)
 }
 
 // Resolve prepares the optional NPC registry reference. An absent slot
 // produces the exact empty prompt input and no semantic registry identity.
 func Resolve(references contracts.ReferenceSet) (*Registry, error) {
-	slot, ok := references.Slots[ReferenceSlot]
-	if !ok {
-		content := []byte(emptyPrompt)
-		projectionDigest := semanticDigest(content)
-		return &Registry{
-			list:             dnd.NPCList{NPCs: []dnd.NPC{}},
-			canonical:        append([]byte(nil), content...),
-			projectionDigest: projectionDigest,
-			promptInput:      contracts.NewLLMInputMaterial(ReferenceSlot, npccodec.MediaType, content, projectionDigest, ""),
-			lookupByKey:      map[string]int{},
-		}, nil
-	}
-	if len(slot.Items) != 1 {
-		return nil, fmt.Errorf("reference slot %q must contain exactly one item", ReferenceSlot)
-	}
-
-	item := slot.Items[0]
-	mediaType, _, err := mime.ParseMediaType(item.MediaType)
+	item, present, err := registryresolver.ResolveOptionalSingleItem(references, npcReferenceSpec())
 	if err != nil {
-		return nil, fmt.Errorf("reference slot %q item media type is invalid", ReferenceSlot)
+		return nil, err
 	}
-	if !strings.EqualFold(mediaType, npccodec.MediaType) {
-		return nil, fmt.Errorf("reference slot %q item media type must be %s", ReferenceSlot, npccodec.MediaType)
-	}
-	if len(item.Content) > MaxBytes {
-		return nil, fmt.Errorf("reference slot %q item is %d bytes, limit %d", ReferenceSlot, len(item.Content), MaxBytes)
+	if !present {
+		return emptyRegistry(), nil
 	}
+	return loadRegistry(item.Content)
+}
 
+func registryResolverConfig() registryresolver.Config[*Registry] {
+	return registryresolver.Config[*Registry]{
+		Reference: npcReferenceSpec(),
+		Absent: func() (*Registry, error) {
+			return emptyRegistry(), nil
+		},
+		Load: loadRegistry,
+		SemanticIdentity: func(registry *Registry) string {
+			return registry.Digest()
+		},
+	}
+}
+
+func npcReferenceSpec() registryresolver.ReferenceSpec {
+	return registryresolver.ReferenceSpec{SlotName: ReferenceSlot, AcceptedMediaType: npccodec.MediaType, MaxBytes: MaxBytes}
+}
+
+func emptyRegistry() *Registry {
+	content := []byte(emptyPrompt)
+	projectionDigest := semanticDigest(content)
+	return &Registry{
+		list:             dnd.NPCList{NPCs: []dnd.NPC{}},
+		canonical:        append([]byte(nil), content...),
+		projectionDigest: projectionDigest,
+		promptInput:      contracts.NewLLMInputMaterial(ReferenceSlot, npccodec.MediaType, content, projectionDigest, ""),
+		lookupByKey:      map[string]int{},
+	}
+}
+
+func loadRegistry(referenceContent []byte) (*Registry, error) {
 	codec := npccodec.New()
-	value, err := codec.Decode(item.Content)
+	value, err := codec.Decode(referenceContent)
 	if err != nil {
 		return nil, fmt.Errorf("decode NPC registry: invalid approved NPC JSON")
 	}

internal/modules/dnd/npcs/registry/registry_test.go

@@ -2,8 +2,10 @@ package registry
 
 import (
 	"bytes"
+	"fmt"
 	"reflect"
 	"strings"
+	"sync"
 	"testing"
 
 	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
@@ -122,6 +124,111 @@ func TestResolverReusesEquivalentCanonicalRegistries(t *testing.T) {
 	}
 }
 
+func TestResolverValidatesStaticAndOperationReferences(t *testing.T) {
+	placeholder, err := NewResolver(referenceSet())
+	if err != nil || placeholder.Seeded().Bound() {
+		t.Fatalf("generated placeholder = %#v, %v; want unbound seed", placeholder, err)
+	}
+
+	valid := listReferenceSet(t, registryFixture())
+	validContent := valid.Slots[ReferenceSlot].Items[0].Content
+	invalidSets := []contracts.ReferenceSet{
+		referenceSet(contracts.ReferenceItem{MediaType: npccodec.MediaType, Content: []byte(`{"npcs":[`)}),
+		referenceSet(contracts.ReferenceItem{MediaType: "text/plain", Content: validContent}),
+		referenceSet(contracts.ReferenceItem{MediaType: npccodec.MediaType, Content: make([]byte, MaxBytes+1)}),
+		referenceSet(
+			contracts.ReferenceItem{MediaType: npccodec.MediaType, Content: validContent},
+			contracts.ReferenceItem{MediaType: npccodec.MediaType, Content: validContent},
+		),
+	}
+	for index, references := range invalidSets {
+		if _, err := NewResolver(references); err == nil {
+			t.Fatalf("NewResolver(invalid %d) error = nil", index)
+		}
+		if _, err := placeholder.Resolve(references); err == nil {
+			t.Fatalf("Resolve(invalid %d) error = nil", index)
+		}
+	}
+
+	staticContent := append([]byte(nil), validContent...)
+	staticReferences := referenceSet(contracts.ReferenceItem{MediaType: npccodec.MediaType, Content: staticContent})
+	seeded, err := NewResolver(staticReferences)
+	if err != nil {
+		t.Fatal(err)
+	}
+	staticContent[0] = '['
+	delete(staticReferences.Slots, ReferenceSlot)
+	if seeded.Seeded().Count() != 2 || seeded.Seeded().CanonicalBytes()[0] != '{' {
+		t.Fatalf("seeded registry retained construction references: %#v", seeded.Seeded())
+	}
+}
+
+func TestResolverCachesEquivalentRegistriesConcurrentlyAndIgnoresCallerDigest(t *testing.T) {
+	resolver, err := NewResolver(referenceSet())
+	if err != nil {
+		t.Fatal(err)
+	}
+	content := listReferenceSet(t, registryFixture()).Slots[ReferenceSlot].Items[0].Content
+	references := referenceSet(contracts.ReferenceItem{MediaType: npccodec.MediaType, Content: content})
+	first, err := resolver.Resolve(references)
+	if err != nil {
+		t.Fatal(err)
+	}
+	second, err := resolver.Resolve(references)
+	if err != nil || second != first {
+		t.Fatalf("raw reuse = %p / %p, %v", first, second, err)
+	}
+	spaced := append([]byte("\n "), content...)
+	spaced = append(spaced, '\n')
+	equivalent, err := resolver.Resolve(referenceSet(contracts.ReferenceItem{MediaType: "APPLICATION/JSON; charset=utf-8", Content: spaced}))
+	if err != nil || equivalent != first {
+		t.Fatalf("semantic reuse = %p / %p, %v", first, equivalent, err)
+	}
+
+	const callers = 24
+	var group sync.WaitGroup
+	errors := make(chan error, callers)
+	for range callers {
+		group.Add(1)
+		go func() {
+			defer group.Done()
+			resolved, err := resolver.Resolve(references)
+			if err != nil || resolved != first {
+				errors <- fmt.Errorf("resolved %p, want %p: %w", resolved, first, err)
+			}
+		}()
+	}
+	group.Wait()
+	close(errors)
+	for err := range errors {
+		t.Error(err)
+	}
+
+	sharedDigest := "sha256:" + strings.Repeat("0", 64)
+	firstItem := contracts.ReferenceItem{MediaType: npccodec.MediaType, Content: content, Digest: sharedDigest}
+	otherList := registryFixture()
+	otherList.NPCs[0].Name = "The Greencloak"
+	otherList.NPCs[0].ID = identity.DeriveID(otherList.NPCs[0].Name)
+	otherContent := listReferenceSet(t, otherList).Slots[ReferenceSlot].Items[0].Content
+	otherItem := contracts.ReferenceItem{MediaType: npccodec.MediaType, Content: otherContent, Digest: sharedDigest}
+	byDigestFirst, err := resolver.Resolve(referenceSet(firstItem))
+	if err != nil {
+		t.Fatal(err)
+	}
+	byDigestOther, err := resolver.Resolve(referenceSet(otherItem))
+	if err != nil || byDigestFirst == byDigestOther || byDigestFirst.Digest() == byDigestOther.Digest() {
+		t.Fatalf("caller digest aliased different registries: %p / %p, %v", byDigestFirst, byDigestOther, err)
+	}
+
+	content[0] = '['
+	if npc, ok := first.Lookup("Mira Thorn"); !ok || npc.Name != "Mira Thorn" {
+		t.Fatalf("resolved registry retained operation bytes: %#v, %t", npc, ok)
+	}
+	if fallback, err := resolver.Resolve(contracts.ReferenceSet{}); err != nil || fallback != resolver.Seeded() || fallback.Bound() {
+		t.Fatalf("fallback = %#v, %v; want unbound seed", fallback, err)
+	}
+}
+
 func registryFixture() dnd.NPCList {
 	return dnd.NPCList{NPCs: []dnd.NPC{
 		{ID: identity.DeriveID("Mira Thorn"), Name: "Mira Thorn", SourceRefs: []source.SourceRef{{SourceID: "session-alpha", StartUnitID: 1, EndUnitID: 2}}},
@@ -147,8 +254,8 @@ func listReferenceSet(t *testing.T, list dnd.NPCList) contracts.ReferenceSet {
 	return referenceSet(contracts.ReferenceItem{SlotName: ReferenceSlot, MediaType: npccodec.MediaType, Content: content})
 }
 
-func referenceSet(item contracts.ReferenceItem) contracts.ReferenceSet {
-	return contracts.ReferenceSet{Slots: map[string]contracts.ResolvedReferenceSlot{ReferenceSlot: {Items: []contracts.ReferenceItem{item}}}}
+func referenceSet(items ...contracts.ReferenceItem) contracts.ReferenceSet {
+	return contracts.ReferenceSet{Slots: map[string]contracts.ResolvedReferenceSlot{ReferenceSlot: {Items: items}}}
 }
 
 func TestProjectionIsStableForEquivalentNormalizedRegistries(t *testing.T) {

internal/modules/dnd/shared/registryresolver/resolver.go

@@ -169,7 +169,7 @@ func (r *Resolver[V]) resolveUncached(references contracts.ReferenceSet) (prepar
 func (r *Resolver[V]) absent() (preparedView[V], error) {
 	value, err := r.config.Absent()
 	if err != nil {
-		return preparedView[V]{}, fmt.Errorf("prepare absent reference slot %q: %w", r.slotName, err)
+		return preparedView[V]{}, err
 	}
 	return preparedView[V]{value: value, identity: r.config.SemanticIdentity(value)}, nil
 }
@@ -177,7 +177,7 @@ func (r *Resolver[V]) absent() (preparedView[V], error) {
 func (r *Resolver[V]) load(content []byte) (preparedView[V], error) {
 	value, err := r.config.Load(content)
 	if err != nil {
-		return preparedView[V]{}, fmt.Errorf("load reference slot %q: %w", r.slotName, err)
+		return preparedView[V]{}, err
 	}
 	identity := strings.TrimSpace(r.config.SemanticIdentity(value))
 	if identity == "" {