You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: gc_job_utils.go
    path of file: ./repos/cockroach/pkg/sql/gcjob
    
    the code of the file until where you have to start completion: // Copyright 2020 The Cockroach Authors.
//
// Use of this software is governed by the Business Source License
// included in the file licenses/BSL.txt.
//
// As of the Change Date specifie
    
func validateDetails(details *jobspb.SchemaChangeGCDetails) error {
	if details.Tenant != nil &&
		(len(details.Tables) > 0 || len(details.Indexes) > 0) {
		return errors.AssertionFailedf(
			"Either field Tenant is set or any of Tables or Indexes: %+v", *details,
		)
	}
	if len(details.Indexes) > 0 {
		if details.ParentID == descpb.InvalidID {
			return errors.Errorf("must provide a parentID when dropping an index")
		}
	}
	return nil
}