"_Unwind_Resume" called upon dead simple fetch request

0

I'm trying to port over some Core Data code over from a test Mac OS application to an iPhone app. I set up a helper method to manage all of the code for the fetches, and everything works great on the Mac OS, but I get this error on the iPhone:

Detected an attempt to call a symbol in system libraries that is not present on the iPhone:
_Unwind_Resume called from function -[NSSQLAdapter _newSelectStatementWithFetchRequest:ignoreInheritance:] in image CoreData.

Here is the code that calls the helper method:

// get authors and title THIS WORKS

    NSArray *bookInfoFetchResults = [self getEntitiesByName:kOC_CD_ObjectKey_bookInfo 
                                        usingPredicateValue:@"contentRoot.bookInfo.bookAuthors > \"\"" 
                                  withSubstitutionVariables:[NSDictionary dictionaryWithObjectsAndKeys:nil] 
                                                    inModel:model 
                                                 andContext:context
                                            sortByAttribute:nil];
    int thisResult = 0;
    int lastResult = [bookInfoFetchResults count];
    for (thisResult = 0; thisResult < lastResult; thisResult++) {
        NSManagedObject *currentResult = [bookInfoFetchResults objectAtIndex:thisResult];
        NSLog(@"bookAuthors: %@", [currentResult valueForKey:kOC_CD_ObjectAttribute_bookAuthors]);
        NSLog(@"bookTitle: %@", [currentResult valueForKey:kOC_CD_ObjectAttribute_bookTitle]);
    }

    // get chapters THIS DOES NOT WORK

    NSArray *chapterFetchResults = [self getEntitiesByName:kOC_CD_ObjectKey_chapter
                                       usingPredicateValue:@"ALL contentRoot.chapters.title > \"\"" 
                                 withSubstitutionVariables:[NSDictionary dictionaryWithObjectsAndKeys:nil] 
                                                   inModel:model 
                                                andContext:context 
                                           sortByAttribute:kOC_CD_ObjectAttribute_key];

    int thisChapterResult = 0;
    int lastChapterResult = [chapterFetchResults count];
    for (thisChapterResult = 0; thisChapterResult < lastChapterResult; thisChapterResult++) {
        NSManagedObject *currentChapterResult = [chapterFetchResults objectAtIndex:thisChapterResult];
        NSLog(@"Chapter %@: %@", [currentChapterResult valueForKey:kOC_CD_ObjectAttribute_number], [currentChapterResult valueForKey:kOC_CD_ObjectAttribute_title]);
    }

The helper method (stripped of error-checking, though removing that didn't change the resulting error):

- (NSArray *) getEntitiesByName:(NSString *)entityName usingPredicateValue:(NSString *)predicateValue withSubstitutionVariables:(NSDictionary *)variablesDict inModel:(NSManagedObjectModel *)aModel andContext:(NSManagedObjectContext *)aContext sortByAttribute:(NSString *)sortingAttribute; {
    NSArray *fetchResults;

        NSString *fetchRequestTemplateName = [NSString stringWithFormat:@"get_%@", entityName];

        NSFetchRequest *fetchRequestTemplate = [[NSFetchRequest alloc] init];
        NSEntityDescription *targetEntityDescription;
        targetEntityDescription = [[aModel entitiesByName] objectForKey:entityName];
        [fetchRequestTemplate setEntity:targetEntityDescription];

        // need to find a way to catch an error here in case we give something that isn't right
        // NSInvalidArgumentException: Unable to parse the format string "MQaynH5bXs"
        NSPredicate *predicateTemplate = [NSPredicate predicateWithFormat:predicateValue]; 
        [fetchRequestTemplate setPredicate:predicateTemplate];
        [aModel setFetchRequestTemplate:fetchRequestTemplate forName:fetchRequestTemplateName];
        [fetchRequestTemplate release];

        if (variablesDict == nil) {
            variablesDict = [NSDictionary dictionaryWithObjectsAndKeys:nil];
            [variablesDict retain];
        }

        NSFetchRequest *fetchRequestToExecute = [aModel fetchRequestFromTemplateWithName:fetchRequestTemplateName substitutionVariables:variablesDict];

        NSError *fetchError;
        fetchResults = [aContext executeFetchRequest:fetchRequestToExecute error:&fetchError]; 

    if ((sortingAttribute != nil) && (fetchResults != nil)) {
        NSSortDescriptor *attributeSorter = [[NSSortDescriptor alloc] initWithKey:sortingAttribute ascending:YES];
        fetchResults = [fetchResults sortedArrayUsingDescriptors:[NSArray arrayWithObject:attributeSorter]];
        [attributeSorter release];
    }

    return fetchResults;

}

The point of failure in the helper method is:

fetchResults = [aContext executeFetchRequest:fetchRequestToExecute error:&fetchError];

Breaking out the code from the helper method doesn't work either.

I don't know if it would help, but after stripping out my error-handling code in my helper method, I get this:

2010-11-30 16:31:30.633 OC Flash Card Core 2[19306:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unsupported predicate (null)'
*** Call stack at first throw:
(
    0   CoreFoundation                      0x02655b99 __exceptionPreprocess + 185
    1   libobjc.A.dylib                     0x027a540e objc_exception_throw + 47
    2   CoreData                            0x02381e86 -[NSSQLGenerator generateSQLStatementForFetchRequest:ignoreInheritance:countOnly:] + 1254
    3   CoreData                            0x023816f0 -[NSSQLAdapter _newSelectStatementWithFetchRequest:ignoreInheritance:] + 480
    4   CoreData                            0x02381501 -[NSSQLAdapter newSelectStatementWithFetchRequest:] + 49
    5   CoreData                            0x023813ae -[NSSQLCore newRowsForFetchPlan:] + 430
    6   CoreData                            0x02380b09 -[NSSQLCore objectsForFetchRequest:inContext:] + 297
    7   CoreData                            0x023806fe -[NSSQLCore executeRequest:withContext:error:] + 206
    8   CoreData                            0x0242e91c -[NSPersistentStoreCoordinator executeRequest:withContext:error:] + 1084
    9   CoreData                            0x0237d897 -[NSManagedObjectContext executeFetchRequest:error:] + 359
    10  OC Flash Card Core 2                0x0000360e -[OCContentImporterObj getEntitiesByName:usingPredicateValue:withSubstitutionVariables:inModel:andContext:sortByAttribute:] + 481
    11  OC Flash Card Core 2                0x00002af7 -[OCContentImporterObj testCoreDataIntegrity] + 188
    12  OC Flash Card Core 2                0x00002864 -[OCContentImporterObj importContent] + 88
    13  OC Flash Card Core 2                0x0000252b -[AppDelegate_iPhone application:didFinishLaunchingWithOptions:] + 91
    14  UIKit                               0x002b4f27 -[UIApplication _callInitializationDelegatesForURL:payload:suspended:] + 1163
    15  UIKit                               0x002b73b0 -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 346
    16  UIKit                               0x002c13ec -[UIApplication handleEvent:withNewEvent:] + 1958
    17  UIKit                               0x002b9b3c -[UIApplication sendEvent:] + 71
    18  UIKit                               0x002be9bf _UIApplicationHandleEvent + 7672
    19  GraphicsServices                    0x02f35822 PurpleEventCallback + 1550
    20  CoreFoundation                      0x02636ff4 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 52
    21  CoreFoundation                      0x02597807 __CFRunLoopDoSource1 + 215
    22  CoreFoundation                      0x02594a93 __CFRunLoopRun + 979
    23  CoreFoundation                      0x02594350 CFRunLoopRunSpecific + 208
    24  CoreFoundation                      0x02594271 CFRunLoopRunInMode + 97
    25  UIKit                               0x002b6c6d -[UIApplication _run] + 625
    26  UIKit                               0x002c2af2 UIApplicationMain + 1160
    27  OC Flash Card Core 2                0x00001ce0 main + 102
    28  OC Flash Card Core 2                0x00001c71 start + 53
)
terminate called after throwing an instance of 'NSException'

But, again, all of this worked flawlessly in the Mac OS. I've tried searching for _Unwind_Resume but it seems to be a bug on Apple's part, and there are at least a dozen different ways to hit it and a dozen different ways to resolve it. The only differential that I can think of is that one attempt only has one instance in the CD store (intentionally so) and the second, the trouble one, can have many. Any ideas?

core-data
ios4
asked on Stack Overflow Nov 30, 2010 by Philip Regan • edited Dec 1, 2010 by Philip Regan

1 Answer

0

Figured out how to get around this: In the predicate used to search, the ALL keyword needs to be ANY.

What I don't understand is why this is the case. The error given seems to be fairly obscure, and the fact that it ends up with EXC_BAD_ACCESS is very troubling. I'm willing to accept the answer for anyone who can explain why there is such a difference between ANY and ALL.

answered on Stack Overflow Dec 1, 2010 by Philip Regan

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