Support for @sum on relationship in NSPredicate

[darronschall]

The collection operators used on relationships within NSPredicate are not currently working. I am trying to use a sum operation but am getting an error. This works in my existing Magical Record / Core Data application, but fails when I switch to EncryptedStore.

I'll describe my problem in terms of the FailedBankCD data model. Perform the following changes:

1. Add a new FailedBankCustomer entity with a 'balance' Integer 32
2. Create a to-many relationship on FailedBankInfo: 'customers' to FailedBankCustomer

// Find only the failed banks where the total balance across all customers > 100
NSPredicate *totalBalancePredicate = [NSPredicate predicateWithFormat:@"customers.@sum.balance > 100"];

[FailedBankInfo MR_fetchAllSortedBy:@"name" ascending:YES withPredicate:totalBalancePredicate groupBy:nil delegate:self];

The follow is the error I'm running into:

+[MagicalRecord(ErrorHandling) defaultErrorHandler:](0x2ec308) Error: no such column: customers.@sum.balance

The following is the generated query that triggers the above error:

SELECT FailedBankInfo.ID FROM FailedBankInfo JOIN FailedBankCustomer AS [customers] ON FailedBankInfo.customers_id = [customers].ID WHERE ([customers.@sum].balance > ?) ORDER BY FailedBankInfo.name ASC;

[gavin-black]

Was able to recreate the issue, thanks for the sample code. Assigning it to myself, but not sure when I'll have free time to get to it.

[gavin-black]

This should be fixed now by commit 4ee23af, at least for the simpler comparison cases (i.e. foo.@sum.bar > faz and @sum.bar > faz). Closing this issue, but let me know if you encounter any more cases where the sum predicate is broken. Thanks again for finding this issue.