DirectoryFileSource, SimpleStringDataSource and SimpleTextDataSource all failed to call super.getInstanceValues() and so missed some values when converted into marshalled provenances. This PR relaxes the check for existing protobufs (as the missing value is a constant) and fixes getInstanceValues for these classes so it is correctly marshalled in the future. It also properly serializes ClusterExemplars from v4.2 which may contain null values.
Motivation
Protobuf serialization will be the only supported form in v5.
Description
DirectoryFileSource,SimpleStringDataSourceandSimpleTextDataSourceall failed to callsuper.getInstanceValues()and so missed some values when converted into marshalled provenances. This PR relaxes the check for existing protobufs (as the missing value is a constant) and fixesgetInstanceValuesfor these classes so it is correctly marshalled in the future. It also properly serializesClusterExemplars from v4.2 which may contain null values.Motivation
Protobuf serialization will be the only supported form in v5.