Provide option to look into xcconfigs for common build settings.

Author: dnkoutso

CHANGELOG.md

@@ -4,7 +4,9 @@
 
 ##### Enhancements
 
-* None.  
+* Provide option to look into xcconfigs for common build settings.
+  [Dimitris Koutsogiorgas](https://github.com/dnkoutso)
+  [#722](https://github.com/CocoaPods/Xcodeproj/pull/722)
 
 ##### Bug Fixes
 
@@ -27,7 +29,6 @@
 * Update PBXProject known_regions attribute to include 'Base'  
   [Liam Nichols](https://github.com/liamnichols)
   [#9187](https://github.com/CocoaPods/CocoaPods/issues/9187)
-  
 
 ##### Bug Fixes
 

lib/xcodeproj/project/object/native_target.rb

@@ -42,7 +42,7 @@ class AbstractTarget < AbstractObject
         #        the key of the build setting.
         #
         # @param [Bool] resolve_against_xcconfig
-        #        wether the resolved setting should take in consideration any
+        #        whether the resolved setting should take in consideration any
         #        configuration file present.
         #
         # @return [Hash{String => String}] The value of the build setting
@@ -74,6 +74,10 @@ def resolved_build_setting(key, resolve_against_xcconfig = false)
         # @param [String] key
         #        the key of the build setting.
         #
+        # @param [Boolean] resolve_against_xcconfig
+        #        whether the resolved setting should take in consideration any
+        #        configuration file present.
+        #
         # @raise  If the build setting has multiple values.
         #
         # @note   As it is common not to have a setting with no value for
@@ -83,8 +87,8 @@ def resolved_build_setting(key, resolve_against_xcconfig = false)
         #
         # @return [String] The value of the build setting.
         #
-        def common_resolved_build_setting(key)
-          values = resolved_build_setting(key).values.compact.uniq
+        def common_resolved_build_setting(key, resolve_against_xcconfig: false)
+          values = resolved_build_setting(key, resolve_against_xcconfig).values.compact.uniq
           if values.count <= 1
             values.first
           else

lib/xcodeproj/scheme/test_action.rb

@@ -58,7 +58,7 @@ def code_coverage_enabled?
         string_to_bool(@xml_element.attributes['codeCoverageEnabled'])
       end
 
-      # @rparam [Bool] flag
+      # @param [Bool] flag
       #         Set whether Clang Code Coverage is enabled ('Gather coverage data' turned ON)
       #
       def code_coverage_enabled=(flag)

spec/fixtures/target.xcconfig

@@ -13,3 +13,5 @@ TARGET_REFERENCE_XCCONFIG_PROJECT = $(USER_DEFINED_XCCONFIG_PROJECT)
 A_BUILD_SETTING_WITH_VALUE = Some value
 TARGET_REFERENCE_ENVIRONMENT =
 TARGET_REFERENCE_ENVIRONMENT_SUBSTITUTION = ${DEFINED_IN_ENVIRONMENT}
+
+APPLICATION_EXTENSION_API_ONLY = YES

spec/project/object/native_target_spec.rb

@@ -245,6 +245,13 @@ module ProjectSpecs
           @target.common_resolved_build_setting('ARCHS').should == 'VALID_ARCHS'
         end
 
+        it 'returns the common resolved build setting for the given key including xcconfig' do
+          target_xcconfig = @project.new_file(fixture_path('target.xcconfig'))
+          @target.build_configuration_list.build_configurations.each { |build_config| build_config.base_configuration_reference = target_xcconfig }
+          @target.common_resolved_build_setting('APPLICATION_EXTENSION_API_ONLY', :resolve_against_xcconfig => false).should.be.nil
+          @target.common_resolved_build_setting('APPLICATION_EXTENSION_API_ONLY', :resolve_against_xcconfig => true).should == 'YES'
+        end
+
         it 'raises if the build setting has multiple values across the build configurations' do
           @target.build_configuration_list.build_configurations.first.build_settings['ARCHS'] = 'arm64'
           @target.build_configuration_list.build_configurations.last.build_settings['ARCHS'] = 'VALID_ARCHS'