OS_OBJECT_USE_OBJC is disabled for all Cocoapods

[rsanchezsaez]

Since iOS 6.0+ and OS X 10.8+, GDC queues are full ObjC objects, and hence they are managed by ARC. This is denoted by the OS_OBJECT_USE_OBJC preprocessor constant having a non-zero value, as seen here.

We are using a project with the Base SDK set to iOS 8.0 and the Deployment Target set to iOS 7.0.

This is the first line of our Podfile:

platform :ios, '7.0'

so all of our Pods project targets have a iOS 7.0 Deployment target as well.

Using this code

#if OS_OBJECT_USE_OBJC
    NSLog(@"OS_OBJECT_USE_OBJC=1")
#else
    NSLog(@"OS_OBJECT_USE_OBJC=0");
#endif

from our AppDelegate correctly prints OS_OBJECT_USE_OBJC=1. Using that code from within any source file on the Pods project seems to print OS_OBJECT_USE_OBJC=0.

I read somewhere that using of GDC queues as objects can be opted-out, but I cannot find any related setting on Xcode's Build Settings. I think this is a Cocoapods bug and that OS_OBJECT_USE_OBJC should be enabled by default within the Pods when the Deployment target is iOS 6.0+ or OS X 10.8+.

See this SO question for additional info.

[segiddins]

@rsanchezsaez where does the OS_OBJECT_USE_OBJC definition usually come from? A system header that must be imported?

[rsanchezsaez]

It comes from libdispatch's os/object.h, which is in turn imported by <dispatch/dispatch.h> (docs). According to the code, it should be 1 when the deployment target is OS X 10.8+ or OS X 6.0+.

#ifndef OS_OBJECT_HAVE_OBJC_SUPPORT
#if defined(__OBJC2__) && !defined(__OBJC_GC__) && ( \
    __MAC_OS_X_VERSION_MIN_REQUIRED >= __MAC_10_8 || \
    __IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_6_0)
    #define OS_OBJECT_HAVE_OBJC_SUPPORT 1
#else
    #define OS_OBJECT_HAVE_OBJC_SUPPORT 0
#endif
#endif

#if OS_OBJECT_HAVE_OBJC_SUPPORT
    #ifndef OS_OBJECT_USE_OBJC
        #define OS_OBJECT_USE_OBJC 1
    #endif
#elif defined(OS_OBJECT_USE_OBJC) && OS_OBJECT_USE_OBJC
    /* Unsupported platform for OS_OBJECT_USE_OBJC=1 */
    #undef OS_OBJECT_USE_OBJC
    #define OS_OBJECT_USE_OBJC 0
#else
    #define OS_OBJECT_USE_OBJC 0
#endif

I'm not sure where the problem is coming from. Adding #import <dispatch/dispatch.h> to the relevant files makes no difference, the printed result from the Pods seems to always be OS_OBJECT_USE_OBJC=0 (and yet it works from the main project's AppDelegate).

[alloy]

This is not a CocoaPods bug. Please see the documentation about the deployment target of a podspec http://guides.cocoapods.org/syntax/podspec.html#deployment_target

And a quick search of the tickets yielded at least:

• Applying -DOS_OBJECT_USE_OBJC=0 doesn't take into account developer integrations #1001
• -DOS_OBJECT_USE_OBJC set to 0 for specs that specify deployment target 5.0, but perform additional checks themselves, leading to leaks #1419

In the future, please read the CONTRIBUTING file before posting new tickets.

[rsanchezsaez]

My bad, sorry about that. Thanks for the clarification! Makes perfect sense.