Frustrating iPhone Build Error

Question

I've been fighting this for a few hours now and I'm getting fed up. My project builds fine with a debug simulator build , release simulator build and a debug device build, but for some reason it won't build with a release device build. I have a static library containing my cocos2d code, and another static library containing a game engine I wrote.

Because the game engine contains categories, I had to use the all_load linker flag to get it to run. Without this flag, the code builds fine. However, I get an unrecognized selector sent to instance exception when I try to run the game.

Here's the first build error:

ld: duplicate symbol _OBJC_CLASS_$_FontLabel in /Users/helixed/Dropbox/Documents/Development/iPhone/Cocos2d/build/Release-iphoneos/libcocos2d.a(FontLabel.o) and /Users/helixed/Dropbox/Documents/Development/iPhone/Cocos2d/build/Release-iphoneos/libcocos2d.a(FontLabel.o)

Ld build/Shapeless.build/Release-iphoneos/Shapeless.build/Objects-normal/armv6/Shapeless normal armv6
cd /Users/helixed/Dropbox/Documents/Development/iPhone/Apps/Shapeless
setenv IPHONEOS_DEPLOYMENT_TARGET 4.0
setenv PATH "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-g++-4.2 -arch armv6 -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.0.sdk -L/Users/helixed/Dropbox/Documents/Development/iPhone/Apps/Shapeless/build/Release-iphoneos -F/Users/helixed/Dropbox/Documents/Development/iPhone/Apps/Shapeless/build/Release-iphoneos -filelist /Users/helixed/Dropbox/Documents/Development/iPhone/Apps/Shapeless/build/Shapeless.build/Release-iphoneos/Shapeless.build/Objects-normal/armv6/Shapeless.LinkFileList -dead_strip -ObjC -all_load -miphoneos-version-min=4.0 /Users/helixed/Dropbox/Documents/Development/iPhone/Cocos2d/build/Release-iphoneos/libChipmunk.a /Users/helixed/Dropbox/Documents/Development/iPhone/Cocos2d/build/Release-iphoneos/libcocos2d.a /Users/helixed/Dropbox/Documents/Development/iPhone/BlackHawk/build/Release-iphoneos/libBlackHawk.a -framework Foundation -framework UIKit -framework CoreGraphics -framework QuartzCore -framework OpenGLES -framework OpenAL -framework AVFoundation -framework AudioToolbox -lz -framework iAd -o /Users/helixed/Dropbox/Documents/Development/iPhone/Apps/Shapeless/build/Shapeless.build/Release-iphoneos/Shapeless.build/Objects-normal/armv6/Shapeless

ld: duplicate symbol _OBJC_CLASS_$_FontLabel in /Users/helixed/Dropbox/Documents/Development/iPhone/Cocos2d/build/Release-iphoneos/libcocos2d.a(FontLabel.o) and /Users/helixed/Dropbox/Documents/Development/iPhone/Cocos2d/build/Release-iphoneos/libcocos2d.a(FontLabel.o)
collect2: ld returned 1 exit status
Command /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-g++-4.2 failed with exit code 1

And here's the second:

Ld build/Shapeless.build/Release-iphoneos/Shapeless.build/Objects-normal/armv7/Shapeless normal armv7
cd /Users/helixed/Dropbox/Documents/Development/iPhone/Apps/Shapeless
setenv IPHONEOS_DEPLOYMENT_TARGET 4.0
setenv PATH "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-g++-4.2 -arch armv7 -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.0.sdk -L/Users/helixed/Dropbox/Documents/Development/iPhone/Apps/Shapeless/build/Release-iphoneos -F/Users/helixed/Dropbox/Documents/Development/iPhone/Apps/Shapeless/build/Release-iphoneos -filelist /Users/helixed/Dropbox/Documents/Development/iPhone/Apps/Shapeless/build/Shapeless.build/Release-iphoneos/Shapeless.build/Objects-normal/armv7/Shapeless.LinkFileList -dead_strip -ObjC -all_load -miphoneos-version-min=4.0 /Users/helixed/Dropbox/Documents/Development/iPhone/Cocos2d/build/Release-iphoneos/libChipmunk.a /Users/helixed/Dropbox/Documents/Development/iPhone/Cocos2d/build/Release-iphoneos/libcocos2d.a /Users/helixed/Dropbox/Documents/Development/iPhone/BlackHawk/build/Release-iphoneos/libBlackHawk.a -framework Foundation -framework UIKit -framework CoreGraphics -framework QuartzCore -framework OpenGLES -framework OpenAL -framework AVFoundation -framework AudioToolbox -lz -framework iAd -o /Users/helixed/Dropbox/Documents/Development/iPhone/Apps/Shapeless/build/Shapeless.build/Release-iphoneos/Shapeless.build/Objects-normal/armv7/Shapeless

ld: duplicate symbol _OBJC_CLASS_$_FontLabel in /Users/helixed/Dropbox/Documents/Development/iPhone/Cocos2d/build/Release-iphoneos/libcocos2d.a(FontLabel.o) and /Users/helixed/Dropbox/Documents/Development/iPhone/Cocos2d/build/Release-iphoneos/libcocos2d.a(FontLabel.o)
collect2: ld returned 1 exit status
Command /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-g++-4.2 failed with exit code 1

This is the only think keeping me from releasing, so I really appreciate the help.

Thanks.

Answer 1

I faced a similar problem, I had accidentally included (#import) the implementation file instead of the header file

When the compiler throws an error that 2 object files contain a duplicate symbol, check for how you have included (#import) the that duplicate symbol's class in the 2 implementation files.

Answer 2

I had this problem with adding both Facebook sdk and Dropbox sdk. The problem was both of the SDks are using having JSON lib so I removed one of them ans it works now.