Open Radar

 
Summary:
While investigating the issue that is now filed as rdar:20924980, I tried creating a fetch request whose predicate was "ALL manyRelateds == nil" in an attempt to find all instances of an entity without any objects related via the manyRelateds property.

Steps to Reproduce:
A sample project is attached which demonstrates this if you select the 3rd cell labeled, "Unattached As via ALL (crash)"

STR separately:
1. Create a Core Data model with A<<->>B many-to-many related entities, whose relationships are A.manyBs and B.manyAs.
2. Create a fetch request for entity A whose predicate is "ALL manyBs == nil".
3. Attempt to execute the fetch request.

Expected Results:
This would be translated into a SQL query which could retrieve all A entities without any related B objects.

Actual Results:
'NSInvalidArgumentException' is thrown, reason: 'Unsupported predicate ALL manyRelateds == nil'

Version:
Xcode 6.3.1 (6D1002), iOS 8.3 (12F69)

Notes:
Workaround: Using an inverted predicate of "NONE manyBs != nil" works, but arriving at it as non-intuitive. "ALL manyBs == nil" seems to be the logical way one would express this, but I am not allowed to.

Configuration:
Any, Simulator or iOS device.

Attachments:
'ManyAToManyB.zip' was successfully uploaded.
(project at <https://github.com/pgor/ManyAToManyB>)