Error on non existing relationship

[Ma-He]

I've got a 'Person' entity with a relationship to a 'Location' entity. But in some cases a 'Person' entity can exists without a 'Location' entity. That's why my JSON model doesn't provide a 'location' key for certain persons.

When I try to deserialize a JSON 'Person' into a ManagedObject without a given location relationship, I get the following error:

*** Assertion failure in -[FEMCache addExistingObject:usingMapping:], /.../FEMCache.m:185
2014-09-08 15:30:47.906 AppName[7866:3191678] 
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'No value for key (locationId) on object (<Location: 0x1782d8330> (entity: Location; id: 0x178826480 <x-coredata:///Location/t149B2931-DA62-4EFC-8C7D-3CFC8058F57A16> ; data: {
city = nil;
country = nil;
houseNumber = nil;
latitude = nil;
locationId = nil;
longitude = nil;
relatedParkingSlot = nil;
streetName = nil;
zipCode = nil;
})) found'

Any suggestions on this?

[dimazen]

@Ma-He
Hello there.

Can you share you mapping description and version?

I assume next case:
You've specified relationship at key "location" (let's assume")
Then Location entity get's created and passed to the cache. However, since there was no data in it - an empty Location is passed.

However, cache can't store objects without Primary Key.. so it crashes..

[Ma-He]

Hi,

yep, that's true. I've specified the location relationship as follows:

[mapping addRelationshipMapping:[self locationMapping]
                                                                   forProperty:PersonRelationships.location
                                                                       keyPath:PersonRelationships.location];

and my 'Location' mapping

+ (FEMManagedObjectMapping *)locationMapping
{
    return [FEMManagedObjectMapping mappingForEntityName:[Location entityName]
                                           configuration:^(FEMManagedObjectMapping *mapping) {
                                               [mapping addAttributeMappingDictionary:@{LocationAttributes.locationId : @"id",
                                                                                        LocationAttributes.houseNumber : @"streetNumber",
                                                                                        LocationAttributes.streetName : @"streetname"}];
                                               [mapping addAttributeMappingFromArray:@[LocationAttributes.city,
                                                                                       LocationAttributes.country,
                                                                                       LocationAttributes.latitude,
                                                                                       LocationAttributes.longitude,
                                                                                       LocationAttributes.zipCode]];

                                               mapping.primaryKey = LocationAttributes.locationId;
                                           }];
}

I'm using the current version 0.3.8

[dimazen]

Basically, we don't have to create relationship if this key not found or represented as Null
Looks like a bug :)

[Ma-He]

That's just what I was thinking :-) First, I've assumed I've done something wrong with my mapping, but after some tests and different JSON representations it looks like a bug to me.
Thanks @poteryaysya for your help ;-)

[dimazen]

@Ma-He
you can help me with pull request (if you'd like to!) ;)
i'll be ready closer to the end of the week

[EsSpectacularrr]

Having the same issue, had to add a null check.

[dimazen]

@JacquesPienaar, @Ma-He
Just get back from my vacation.
I'll take a look in a few days

[dimazen]

@Ma-He, @JacquesPienaar
Can you, guys, share JSON input for me?
Basically, it happens, when there is a mapping for some relationship, but no object presented in JSON, correct?

[EsSpectacularrr]

Correct

eg:

[mapping addToManyRelationshipMapping:[self promotion] forProperty:@"promotions" keyPath:@"promotions"];

json
"promotions": null

[dimazen]

@JacquesPienaar thanks for help!

[dimazen]

@JacquesPienaar
can reproduce it on to-one relationship, when key in JSON is missing.
it generate empty entity with nil fields. (which is obviously a bug)