Ref T1191. Currently if a developer forgot to specify a column type, storage adjust aborts explosively mid-stream. Instead:
- Make this a formal error with an unambiugous name/description instead of something you sort of infer by seeing "<unknown>".
- Make this error prevent generation of adjustment warnings, so we don't try to ALTER TABLE t CHANGE COLUMN c <unknown>, which is nonsense.
- When schemata errors exist, surface them prominiently in storage adjust.
- Once storage upgrade runs storage adjust automatically (soon), this will make it relatively difficult to miss these errors.
- Letting these errors slip through no longer escalates into a more severe issue.