Asserting that an entity has a MOC

[notjosh]

I'll save the next poor sucker the hassle of diagnosing this the long way.

(For those playing at home, in my case, when GCC_OPTIMIZATION_LEVEL == 0, it worked fine. I was only getting errors in prod builds. Don't be a fool like me, and keep a reference to your MOC so you can, you know, do work within it.)

[robb]

Thanks ✨

[jspahrsummers]

I think it's legal to have a managed object without a context. Especially for this use, where you just want to parse a MTLModel out of it, it seems reasonable to allow that.

[notjosh]

Actually, yeah, you're right. That's a very valid use case. However, without a valid context, the innards of performInContext() won't do a whole lot.

To cater for that use case, you'd have to check for nil and executing the block param directly to get something meaningful back. I wonder if that'd have solved my issue? I'm not sure if that'll have undesired side-effects though.

[robb]

Sorry, I'll revert the commit

[notjosh]

Actually, given that NSConfinementConcurrencyType is 0, the block will run despite context being nil. So you're right, this is probably better off without the assert for that one use case.

I still think it would make sense to address the problematic use case though. So, maybe instead have an assert that checks -[NSManagedObject isFault] as well as nil context? AFAIK, it will only ever fault if there's persisted data we need to access, in which case it needs a context.

[jspahrsummers]

👍 on isFault.

Let's also add explicit checks for context == nil with performInContext() too. I don't like depending on the value of NSConfinementConcurrencyType.