Resolve nested inheritance in destination scopes

internal/engine/inheritance.go

@@ -40,6 +40,10 @@ type siblingFrame struct {
 // Nested instructions remain in the returned templates for destination-local
 // resolution. This private entry point does not participate in public loading.
 func expandSiblingDefinitions(scope *document.Node, scopePath Path) (*inheritanceScope, []Diagnostic) {
+	return expandSiblingDefinitionsWithLimits(scope, scopePath, defaultProjectionLimits())
+}
+
+func expandSiblingDefinitionsWithLimits(scope *document.Node, scopePath Path, limits projectionLimits) (*inheritanceScope, []Diagnostic) {
 	if scope == nil || scope.Kind != document.Mapping {
 		return nil, []Diagnostic{{
 			Code: CodeInheritanceInvalid, Severity: SeverityError, Path: scopePath,
@@ -58,6 +62,21 @@ func expandSiblingDefinitions(scope *document.Node, scopePath Path) (*inheritanc
 	resolved := make(map[string]*document.Node, len(byName))
 	state := make(map[string]uint8, len(byName))
 	result := &inheritanceScope{}
+	retained := 1 // scope mapping node
+	for _, entry := range scope.Mapping {
+		if entry.Value.Kind == document.Mapping {
+			continue
+		}
+		remaining := limits.nodes - retained - 1
+		if limits.nodes >= 0 && remaining < 0 {
+			return nil, []Diagnostic{inheritanceBudgetDiagnostic(scopePath.Key(entry.Key), entry.Value.Location)}
+		}
+		count, within := inheritanceLowerBoundCount(entry.Value, remaining)
+		if !within {
+			return nil, []Diagnostic{inheritanceBudgetDiagnostic(scopePath.Key(entry.Key), entry.Value.Location)}
+		}
+		retained += 1 + count // key and value subtree
+	}
 	for _, name := range names {
 		if byName[name].Value.Kind != document.Mapping || state[name] == 2 {
 			continue
@@ -109,6 +128,18 @@ func expandSiblingDefinitions(scope *document.Node, scopePath Path) (*inheritanc
 			}
 
 			payload := withoutInheritanceDirective(entry.Value)
+			if limits.nodes >= 0 {
+				remaining := limits.nodes - retained - 1 // the sibling key
+				within := false
+				if frame.hasParent {
+					within = inheritanceOverlayLowerBoundWithin(resolved[frame.parent], payload, remaining)
+				} else {
+					within = inheritanceLowerBoundWithin(payload, remaining)
+				}
+				if !within {
+					return nil, []Diagnostic{inheritanceBudgetDiagnostic(path, entry.Value.Location)}
+				}
+			}
 			if frame.hasParent {
 				parent := resolved[frame.parent]
 				merged := document.Clone(parent)
@@ -124,6 +155,8 @@ func expandSiblingDefinitions(scope *document.Node, scopePath Path) (*inheritanc
 			} else {
 				resolved[frame.name] = document.Clone(payload)
 			}
+			count, _ := inheritanceLowerBoundCount(resolved[frame.name], limits.nodes)
+			retained += 1 + count
 			state[frame.name] = 2
 			stack = stack[:len(stack)-1]
 		}
@@ -140,6 +173,9 @@ func expandSiblingDefinitions(scope *document.Node, scopePath Path) (*inheritanc
 		}
 	}
 	result.root = &root
+	if !inheritanceLowerBoundWithin(result.root, limits.nodes) {
+		return nil, []Diagnostic{inheritanceBudgetDiagnostic(scopePath, scope.Location)}
+	}
 	return result, nil
 }