Mogenerator and ARC in XCode 4.6

Question

I am just getting started with integrating mogenerator into an app project with Core Data, per recommendations as a best practice. I added the following build script, with a flag to support ARC.

mogenerator -m FavesDataModel.xcdatamodeld/FavesDataModel.xcdatamodel --template-var arc=true

The script successfully builds all the necessary classes and subclasses. At that time, I copied all the generated files into my project. Initially, I got a clean successful build. However, when trying another build (without making any changes), it fails with the following ARC error:

ARC forbids Objective-C objects in structs or unions

The errors occur in the files generated with an underscore. Interestingly, when the build script builds the files as follows:

extern const struct FavoriteAttributes {
    __unsafe_unretained NSString *maxCFS;
    __unsafe_unretained NSString *maxFeet;
    __unsafe_unretained NSString *minCFS;
    __unsafe_unretained NSString *minFeet;
    __unsafe_unretained NSString *stationIdentifier;
    __unsafe_unretained NSString *stationRealName;
    __unsafe_unretained NSString *stationState;
} FavoriteAttributes;

However, after a successful build, XCode removes the __unsafe_unretained attribute.

Are there known issues with using mogenerator with ARC turned on? Any ideas of a solution or workaround? Thanks! V

Answer 1

Try removing --template-var arc=true from your build script.

Then in XCode, Project Properties, Compile sources, set the problem files to have the following flag

fno-objc-arc

This will turn off ARC for only those files.