SMLBuildSettings

Using the merged xcconfig file.

Settings up scheme scripts

Open the schemes editor. (cmd + <) Add a new run script action to the Pre-actions under Build.

Merge partial xcconfig files

ruby "${SRCROOT}/SMLBuildSettings/configurations.rb" --reset "${SRCROOT}/SMLBuildSettings"
ruby "${SRCROOT}/SMLBuildSettings/configurations.rb" --merge Config-1.xcconfig Config-2.xcconfig "${SRCROOT}/Configurations"

Example Output

Config-1.xcconfig

GCC_PREPROCESSOR_DEFINITIONS = CONFIG_FLAG_A=1 $(inherited)

Config-2.xcconfig

GCC_PREPROCESSOR_DEFINITIONS = CONFIG_FLAG_B=1 $(inherited)

Config-Merged.xcconfig (after merge)

//
// **** Added By Configurations.rb ****
// **** Path: Config-1.xcconfig ****
//

Config1xcconfigGCC_PREPROCESSOR_DEFINITIONS = CONFIG_FLAG_A=1 $(inherited)
//
// **** Added By Configurations.rb ****
// **** Path: Config-2.xcconfig ****
//

Config2xcconfigGCC_PREPROCESSOR_DEFINITIONS = CONFIG_FLAG_B=1 $(inherited)
//
// **** Added By Configurations.rb ****
//

GCC_PREPROCESSOR_DEFINITIONS = $(Config1xcconfigGCC_PREPROCESSOR_DEFINITIONS) $(Config2xcconfigGCC_PREPROCESSOR_DEFINITIONS)
GCC_PREPROCESSOR_DEFINITIONS = $(Config1xcconfigGCC_PREPROCESSOR_DEFINITIONS) $(Config2xcconfigGCC_PREPROCESSOR_DEFINITIONS)

Results

Tips & Tricks

• Create multiple schemes to setup unique build configurations composed of xcconfig partials.

• Use environment variables and shell scripts to take conditional builds a step further.

• Always include $(inherited) in your partials, or some settings may be ignored

• Use OTHER_LDFLAGS to conditionally link libraries

    OTHER_LDFLAGS = $(inherited) -l PonyDebugger
    GCC_PREPROCESSOR_DEFINITIONS = $(inherited) ENABLE_PONY_DEBUGGER=1
  

Complaints

Config-Merged.xconfig should be committed to your repo to keep Xcode's build configuration/xcconfig setup from complaining, this often means you'll have to be mindful to not commit the merged version of it. This can be mitigated by using the reset flag of configurations.rb in a post build action.