Roll back failed dynamic descriptor builds

internal/engine/value_operation.go

@@ -40,9 +40,11 @@ func (o *valueOperation) dynamicDescriptor(current reflect.Type, path Path) (*ty
 	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 {
+		builder.rollback()
 		return nil, &projectionIssue{code: CodeSchemaDynamicType, path: path.clone(), message: "dynamic configuration value has an unsupported type"}
 	}
 	if descriptorContainsSecret(descriptor, make(map[*typeDescriptor]bool)) {
+		builder.rollback()
 		return nil, &projectionIssue{code: CodeSchemaDynamicType, path: path.clone(), message: "dynamic configuration values cannot establish secret-reference semantics"}
 	}
 	return descriptor, nil