Cache approved dynamic descriptors per operation

docs/roadmap/implementation.md

@@ -461,6 +461,13 @@ Focused check: `go test ./internal/engine -run 'History|Explain|Inheritance|Over
 Finding: **A05**; requires Stage 2.
 Owners: `internal/engine/value_operation.go`, projection/clone tests.
 
+Status: **complete** (A05). Prior completed commits: `2736ddf`, `deb9aa5`,
+`ae3408a`, `ea27f17`, `08a8c25`, `877c497`, `8aba43d`, `7bf2f0c`,
+`0f9ecf1`, `119b42c`, `247a12b`, `4fcff5f`, `12d350a`. Validation passed:
+`env GOTOOLCHAIN=local GOPROXY=off GOTELEMETRY=off go test ./internal/engine -run 'Dynamic|Projection|Clone|Resolution' -count=1`,
+`env GOTOOLCHAIN=local GOPROXY=off GOTELEMETRY=off go test ./internal/engine -count=1`,
+and `git diff --check`.
+
 Add an operation-local set of successfully approved concrete types/descriptors.
 After a completed descriptor build and a full successful secret-eligibility walk,
 record approval. Subsequent values of that type in the same `valueOperation` reuse

internal/engine/dynamic_descriptor_transaction_test.go

@@ -4,6 +4,8 @@ import (
 	"errors"
 	"reflect"
 	"testing"
+
+	"gitea.maximumdirect.net/eric/ConfigKit/internal/document"
 )
 
 type unsupportedDynamicRoot struct {
@@ -63,6 +65,9 @@ func TestDynamicDescriptorFailuresRollBackProvisionalTypes(t *testing.T) {
 	if _, issue := operation.dynamicDescriptor(reflect.TypeFor[unsupportedDynamicRoot](), Keys("failure")); issue == nil || issue.code != CodeSchemaDynamicType {
 		t.Fatalf("unsupported dynamic descriptor issue = %#v", issue)
 	}
+	if _, approved := operation.approvedDynamic[reflect.TypeFor[unsupportedDynamicRoot]()]; approved {
+		t.Fatal("unsupported dynamic descriptor was cached as eligible")
+	}
 	if schema.types[reflect.TypeFor[map[string]string]()] != prior {
 		t.Fatal("failed build removed a previously completed descriptor")
 	}
@@ -87,9 +92,69 @@ func TestDynamicDescriptorFailuresRollBackProvisionalTypes(t *testing.T) {
 	if _, issue := secretOperation.dynamicDescriptor(reflect.TypeFor[secretDynamicRoot](), Keys("secret")); issue == nil || issue.code != CodeSchemaDynamicType {
 		t.Fatalf("dynamic secret eligibility issue = %#v", issue)
 	}
+	if len(secretOperation.approvedDynamic) != 0 {
+		t.Fatalf("secret-bearing dynamic descriptor was cached as eligible: %#v", secretOperation.approvedDynamic)
+	}
 	for _, current := range []reflect.Type{reflect.TypeFor[secretDynamicRoot](), reflect.TypeFor[secretDynamicNested](), reflect.TypeFor[Secret]()} {
 		if _, exists := secretSchema.types[current]; exists {
 			t.Errorf("secret eligibility failure retained provisional descriptor for %v", current)
 		}
 	}
 }
+
+type wideDynamicEligibilityValue struct {
+	Alpha    string
+	Bravo    string
+	Charlie  string
+	Delta    string
+	Echo     string
+	Foxtrot  string
+	Golf     string
+	Hotel    string
+	India    string
+	Juliet   string
+	Kilo     string
+	Lima     string
+	Mike     string
+	November string
+	Oscar    string
+	Papa     string
+}
+
+type repeatedNilDynamicEligibilityConfig struct {
+	Values []any
+}
+
+func TestDynamicEligibilityIsReusedWithinProjectionOperation(t *testing.T) {
+	schema, schemaIssue := buildSchema(reflect.TypeFor[repeatedNilDynamicEligibilityConfig](), testSecretBinding())
+	if schemaIssue != nil {
+		t.Fatalf("schema issue = %#v", schemaIssue)
+	}
+	values := make([]any, 32)
+	for index := range values {
+		values[index] = (*wideDynamicEligibilityValue)(nil)
+	}
+	configuration := repeatedNilDynamicEligibilityConfig{Values: values}
+	operation := valueOperation{schema: schema, limits: defaultProjectionLimits(), active: make(map[valueVisit]bool)}
+	node, issue := operation.project(reflect.ValueOf(configuration), schema.root, Path{}, 0)
+	if issue != nil {
+		t.Fatalf("repeated typed-nil projection issue = %#v", issue)
+	}
+	if len(node.Mapping) != 1 || len(node.Mapping[0].Value.Sequence) != len(values) {
+		t.Fatalf("projected repeated values = %#v", node)
+	}
+	for index, child := range node.Mapping[0].Value.Sequence {
+		if child.Kind != document.Null {
+			t.Errorf("projected value %d kind = %v, want null", index, child.Kind)
+		}
+	}
+	current := reflect.TypeFor[*wideDynamicEligibilityValue]()
+	if len(operation.approvedDynamic) != 1 || operation.approvedDynamic[current] == nil ||
+		operation.approvedDynamic[current] != schema.types[current] {
+		t.Fatalf("operation eligibility cache = %#v", operation.approvedDynamic)
+	}
+	otherOperation := valueOperation{schema: schema, limits: defaultProjectionLimits(), active: make(map[valueVisit]bool)}
+	if len(otherOperation.approvedDynamic) != 0 {
+		t.Fatalf("dynamic eligibility leaked into another operation: %#v", otherOperation.approvedDynamic)
+	}
+}

internal/engine/value_operation.go

@@ -24,13 +24,14 @@ type valueVisit struct {
 	length int
 }
 
-// valueOperation owns one traversal's cycle and budget state and reuses the
+// valueOperation owns one traversal's cycle and budget state, and caches
-// current load's descriptor cache for dynamic values.
+// dynamic descriptors approved for that traversal.
 type valueOperation struct {
 	cloneMode       secretCloneMode
 	schema          *schemaDescriptor
 	limits          projectionLimits
 	active          map[valueVisit]bool
+	approvedDynamic map[reflect.Type]*typeDescriptor
 	nodes           int
 	nodeCredits     int
 }
@@ -39,6 +40,9 @@ func (o *valueOperation) dynamicDescriptor(current reflect.Type, path Path) (*ty
 	if o.schema.secrets.Type != nil && current == o.schema.secrets.Type {
 		return nil, &projectionIssue{code: CodeSchemaDynamicType, path: path.clone(), message: "dynamic configuration values cannot establish secret-reference semantics"}
 	}
+	if descriptor, approved := o.approvedDynamic[current]; approved {
+		return descriptor, nil
+	}
 	builder := schemaBuilder{cache: o.schema.types, building: make(map[reflect.Type]bool), secrets: o.schema.secrets}
 	descriptor, issue := builder.describe(current, path)
 	if issue != nil {
@@ -49,6 +53,10 @@ func (o *valueOperation) dynamicDescriptor(current reflect.Type, path Path) (*ty
 		builder.rollback()
 		return nil, &projectionIssue{code: CodeSchemaDynamicType, path: path.clone(), message: "dynamic configuration values cannot establish secret-reference semantics"}
 	}
+	if o.approvedDynamic == nil {
+		o.approvedDynamic = make(map[reflect.Type]*typeDescriptor)
+	}
+	o.approvedDynamic[current] = descriptor
 	return descriptor, nil
 }