I have an instance currently running on 2.9.0.beta4, and I needed to migrate it, so I did the basic backup/restore, but restore failed on the new instance. I decided then to try to update the original instance, but it failed also. Both failed, seemingly for the same reason, during the db:migrate command.
It is, and it’s worked in every other case we’ve seen.  isn’t a valid value, even in the old format, so this particular case is quite surprising. Maybe it’s left over from some manual work on the console, or a bad import
If we get more reports, we’ll be sure to add an automated fix for this case.
Ah. Right. Usually when I get that error, it’s becuase I messed up such that I was accessing the wrong variable or something. But maybe that was the state that it was left in after all of the other ones had been deleted. But, really, I wasn’t paying close enough attention.
Our ‘list’ settings are a thin UI over pipe-delimited strings, so in theory an empty list should be stored as an empty string. But you make a good point - maybe someone was trying to empty the list and did something like this by accident: