One of the big changes between Lisp and Scheme was the move from "variables with dynamic extent" to “variables with lexical extent.” It seems like dynamic extent is making a comeback! In CoreData you have to kind of thread your ModelObjectContext through the graph of objects. In SwiftData, objects pick up their ModelContext through the environment. (This isn't a SwiftUI snippet!) Everything old is new again.

I can’t believe this, but it looks like — for the third time! — we’re going to raise a sparrow that was pushed out of its nest.

I didn't realize that you can right-click on a TimeMachine backup destination in Settings! The right-click menu lets you verify backups. If the backup fails verification, TimeMachine asks you if you want to erase and start over. (Unfortunately, "erase and start over" is something I've had to do often in the past couple of years. TimeMachine used to be reliable…)