There seems to be a crash coming from this log message. This is logged when the sync source resolver can't find an appropriate sync source. However, getSyncSource() requires that there be a valid sync source stored in the response object and that the return status is OK. As a result, this will always crash if we reach this log message.

The reason this hasn't happened too often is probably because this is only logged as part of primary catchup, and it seems less likely that we will become elected to primary, then be unable to find a sync source.