CoreStore: iOS 10: Sectioned ListMonitor crashing with EXC_BAD_ACCESS

Since upgrading to CoreStore v2.1.0 and Xcode 8 I’m getting a repeatable crash whenever I try to display a view that is backed by a sectioned ListMonitor on the iOS 10 simulator (it’s fine on iOS 9):

If I change the monitor to a non-sectioned list it’s fine.

I’ve tried enabling Zombie Objects but nothing helpful is logged.

Also, why is CoreStore warning me that I’m overwriting a Where clause? Isn’t that the point of refetch() anyway?

I’m at a bit of a loss at how to fix this one, any help would be much appreciated.

About this issue

Original URL
State: closed
Created 8 years ago
Comments: 44 (21 by maintainers)

Commits related to this issue

workaround #100 (NSFetchRequest.affectedStores ARC bug) — committed to JohnEstropia/CoreStore by JohnEstropia 8 years ago
Revert workaround for iOS 10 NSFetchedResultsController (#100) — committed to JohnEstropia/CoreStore by JohnEstropia 5 years ago

Most upvoted comments

Yep, that fixes it. 👍

a13xb on Feb 28, 2019

Oh boy 😅 @a13xb Thanks for testing this out! I’ll try to get a fix up in the next update

JohnEstropia on Feb 28, 2019

My hunch was correct, but I hit a roadblock. First, using @jamesbebbington’s test project, go to CoreStoreFetchRequest.swift and comment out the override for affectedStores

// MARK: - CoreStoreFetchRequest

// Bugfix for NSFetchRequest messing up memory management for `affectedStores`
// http://stackoverflow.com/questions/14396375/nsfetchedresultscontroller-crashes-in-ios-6-if-affectedstores-is-specified
internal final class CoreStoreFetchRequest: NSFetchRequest {

//    @objc
//    override var affectedStores: [NSPersistentStore]? {
//        
//        get { return super.affectedStores }
//        set { super.affectedStores = newValue }
//    }
}

This fixed the crash for me. Here’s the problem: doing this breaks CoreStore’s unit tests and demo app. The difference I can think of is that the test project imports CoreStore as a Cocoapod, and CoreStore’s test cases and demo app imports it as a framework. There must be a Cocoapod compiler setting somewhere that somehow fixes the bug that override var affectedStores was trying to fix.

I’ll continue investigating this tomorrow, but if you find other hints please do share. In the meantime, you can try commenting out the code above.

JohnEstropia on Sep 23, 2016

I might have a hunch on why this is happening. Let me test for a while

JohnEstropia on Sep 23, 2016

Ok, I think I can reproduce the issue: In CountriesTableViewController change the monitorSectionedList part to:

    let countries: ListMonitor<Country> = CoreStore.monitorSectionedList(
        From(Country),
        SectionBy("continent.name"),
        OrderBy(.Ascending("continent.name")),
        Tweak { (fetchRequest) -> Void in
            fetchRequest.fetchBatchSize = 20
        }
    )

Crashes every time.

laeroah on Sep 23, 2016