Protect paired history snapshots from disclosure

docs/roadmap/implementation.md

@@ -368,6 +368,8 @@ Stage 11 verifies the resulting disclosure through the safe rendering boundary.
 
 ## Stage 11 — Mask paired snapshots and preserve safe disclosure
 
+**Status:** Complete. Focused moved, removed, dynamic-tag, dependency, secret, and diff checks passed.
+
 **Scope:** snapshot rendering and inspection integration.
 
 1. Mask a moved explanation's before and after snapshots using their respective

internal/engine/resolution_compare_test.go

@@ -588,3 +588,90 @@ func TestRegisteredResolutionKeepsRemovedSensitivity(t *testing.T) {
 		t.Fatal("removed historical sensitivity lost")
 	}
 }
+
+func TestMovedAndRemovedSensitiveValuesStayHidden(t *testing.T) {
+	type item struct {
+		ID    string `yaml:"id"`
+		Value string `yaml:"value"`
+	}
+	type config struct {
+		Items   []item `yaml:"items"`
+		Derived string `yaml:"derived"`
+	}
+	for _, remove := range []bool{false, true} {
+		definition := DefinitionWithSequenceIdentityRegistrations(Definition[config]{
+			Secret: func(path Path) bool { return path.String() == "/items/1/value" },
+			Resolve: func(value *config, r *Resolution) error {
+				value.Items[0], value.Items[1] = value.Items[1], value.Items[0]
+				value.Derived = value.Items[1].Value
+				r.RecordNormalization(Keys("items").Index(1).Key("value"), "retain value", Keys("derived"))
+				if remove {
+					value.Items = value.Items[:1]
+				}
+				r.RecordNormalization(Keys("items"), "update records")
+				r.RecordNormalization(Keys("derived"), "derive", Keys("items").Index(1).Key("value"))
+				return nil
+			},
+		}, []SequenceIdentityRegistrationInput{{ExactPath: pathPointer(Keys("items")), IdentityFields: []string{"id"}}})
+		result, err := testLoad(Bytes("records", []byte("items: [{id: a, value: PRIVATE_CANARY}, {id: b, value: other}]\n")), Options[config]{Definition: definition})
+		if err != nil {
+			t.Fatal(err)
+		}
+		for _, path := range []Path{Keys("items"), Keys("items").Index(0), Keys("items").Index(1), Keys("derived")} {
+			explanation, ok := result.Inspection.Explain(path)
+			if !ok {
+				continue
+			}
+			if strings.Contains(explanation.Effective.YAML, "PRIVATE_CANARY") {
+				t.Fatalf("effective leaked at %s", path.String())
+			}
+			for _, change := range explanation.History {
+				if strings.Contains(change.Before.YAML, "PRIVATE_CANARY") || strings.Contains(change.After.YAML, "PRIVATE_CANARY") {
+					t.Fatalf("history leaked at %s: %#v", path.String(), change)
+				}
+			}
+		}
+		var output strings.Builder
+		if err := result.Inspection.WriteEffective(&output); err != nil || strings.Contains(output.String(), "PRIVATE_CANARY") {
+			t.Fatalf("effective output leaked: %q, %v", output.String(), err)
+		}
+	}
+}
+
+func TestMovedDynamicTaggedValueStaysHidden(t *testing.T) {
+	type sensitive struct {
+		ID    string `yaml:"id"`
+		Token string `yaml:"token" configkit:"secret"`
+	}
+	type config struct {
+		Items []any `yaml:"items"`
+	}
+	definition := DefinitionWithSequenceIdentityRegistrations(Definition[config]{
+		Defaults: func() config {
+			return config{Items: []any{sensitive{ID: "a", Token: "DYNAMIC_PRIVATE_CANARY"}, sensitive{ID: "b", Token: "other"}}}
+		},
+		Resolve: func(value *config, r *Resolution) error {
+			value.Items[0], value.Items[1] = value.Items[1], value.Items[0]
+			r.RecordNormalization(Keys("items"), "reorder")
+			return nil
+		},
+	}, []SequenceIdentityRegistrationInput{{ExactPath: pathPointer(Keys("items")), IdentityFields: []string{"id"}}})
+	result, err := testLoad(NoSource(), Options[config]{Definition: definition})
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, path := range []Path{Keys("items"), Keys("items").Index(1).Key("token")} {
+		explanation, ok := result.Inspection.Explain(path)
+		if !ok {
+			t.Fatalf("missing explanation %s", path.String())
+		}
+		if strings.Contains(explanation.Effective.YAML, "DYNAMIC_PRIVATE_CANARY") {
+			t.Fatal("effective value leaked")
+		}
+		for _, change := range explanation.History {
+			if strings.Contains(change.Before.YAML, "DYNAMIC_PRIVATE_CANARY") || strings.Contains(change.After.YAML, "DYNAMIC_PRIVATE_CANARY") {
+				t.Fatal("history leaked")
+			}
+		}
+	}
+}

internal/engine/secret.go

@@ -92,6 +92,9 @@ func classifySecretPathsWithEvidence(schema *schemaDescriptor, predicate func(Pa
 			if target, matched := model.resolutionPayload.correspondence.finalPath(path); matched {
 				projected[target.String()] = target
 			}
+			if prior, matched := model.resolutionPayload.correspondence.entryPath(path); matched {
+				projected[prior.String()] = prior
+			}
 		}
 		for pointer, path := range projected {
 			paths[pointer] = path