autosavesInPlace causes New Document save to fail - objective-c

Question

I have a NSPersistentDocument based app which fails to save a new document when autosavesInPlace is set to return YES , return NO and the problem disappears.
I create a new document
Make some changes
Save it , thus running NSSaveAsOperation , the name of the document and the URL changes and all appears to be well but the next save will throw a very descriptive
NSPersistentStoreSaveError = 134030, // unclassified save error - something we depend on returned an error
This only happens when the document attempts to run a save after a NSSaveAsOperation. Any other save type will work fine as in changes to existing doc. Interesting effect is that if i dont change name or location i dont get this issue either.
Im getting an exception backtrace of
frame #0: 0x00007fff988143c5 libobjc.A.dylibobjc_exception_throw
frame #1: 0x00007fff94c5f5f9 CoreData-[NSPersistentStore(_NSInternalMethods) _preflightCrossCheck] + 697
frame #2: 0x00007fff94c3198b CoreData-[NSPersistentStoreCoordinator executeRequest:withContext:error:] + 603
frame #3: 0x00007fff94c5aa98 CoreData-[NSManagedObjectContext save:] + 456
frame #4: 0x00007fff91baa101 AppKit-[NSPersistentDocument writeToURL:ofType:forSaveOperation:originalContentsURL:error:] + 3743
frame #5: 0x0000000100002de7 ZZZZ-[ZZZZDocument writeToURL:ofType:forSaveOperation:originalContentsURL:error:] + 135 at ZZZZDocument.m:209
frame #6: 0x00007fff91baabc7 AppKit-[NSPersistentDocument writeSafelyToURL:ofType:forSaveOperation:error:] + 611
frame #7: 0x0000000100002ea3 ZZZZ-[ZZZZDocument writeSafelyToURL:ofType:forSaveOperation:error:] + 115 at ZZZZDocument.m:223
any ideas?

Answer 1

Its not possible for a un-wrappered core data file
In the event you attempt to trap NSSaveAsOperation and do a migrate on the persistent store for that enum the construction of the ...-journal file will fail to create as its outside the sandbox.
-(void)saveToURL:(NSURL *)url ofType:(NSString *)typeName forSaveOperation:(NSSaveOperationType)saveOperation completionHandler:(void (^)(NSError *))completionHandler
{
NSLog(#" save op = %ld to %# ",saveOperation,url);
NSURL *targeturl = url;
if(saveOperation == NSSaveAsOperation)
{
//migrate pstore
NSPersistentStore *store = [self.managedObjectContext.persistentStoreCoordinator.persistentStores lastObject];
if (store)
{
NSMutableDictionary *opts = [NSMutableDictionary dictionary];
[opts setValue:[NSNumber numberWithBool:YES] forKey:NSInferMappingModelAutomaticallyOption];
[opts setValue:[NSNumber numberWithBool:YES] forKey:NSMigratePersistentStoresAutomaticallyOption];
NSError *error = NULL;
NSPersistentStore *newstore = [self.managedObjectContext.persistentStoreCoordinator migratePersistentStore:store toURL:url options:opts withType:store.type error:&error];
if(newstore == nil)
{
NSLog(#"migration error %#",[error localizedDescription]);
}
self.fileURL = url;
}
}
[super saveToURL:targeturl ofType:typeName forSaveOperation:saveOperation completionHandler:completionHandler];
}
So we need to wrapper the file in a bundle/folder which is non-trivial using the NSPersistentDocument framework.
Heres waiting for NSManagedDocument (thats a wishing well API)