showBuildSettings does not require to call clean

fastlane_core/lib/fastlane_core/helper.rb

@@ -213,6 +213,13 @@ def self.keychain_path(name)
       keychain_path
     end
 
+    # @return true if XCode version is higher than 8.3
+    def self.xcode_at_least?(version)
+      FastlaneCore::UI.user_error!("Unable to locate Xcode. Please make sure to have Xcode installed on your machine") if xcode_version.nil?
+      v = xcode_version
+      Gem::Version.new(v) >= Gem::Version.new(version)
+    end
+
     # @return the full path to the iTMSTransporter executable
     def self.itms_path
       return ENV["FASTLANE_ITUNES_TRANSPORTER_PATH"] if FastlaneCore::Env.truthy?("FASTLANE_ITUNES_TRANSPORTER_PATH")

fastlane_core/lib/fastlane_core/project.rb

@@ -279,9 +279,14 @@ def xcodebuild_parameters
     def build_xcodebuild_showbuildsettings_command
       # We also need to pass the workspace and scheme to this command.
       #
-      # The 'clean' portion of this command is a workaround for an xcodebuild bug with Core Data projects.
+      # The 'clean' portion of this command was a workaround for an xcodebuild bug with Core Data projects.
+      # This xcodebuild bug is fixed in Xcode 8.3 so 'clean' it's not necessary anymore
       # See: https://github.com/fastlane/fastlane/pull/5626
-      command = "xcodebuild clean -showBuildSettings #{xcodebuild_parameters.join(' ')}"
+      if FastlaneCore::Helper.xcode_at_least?('8.3')
+        command = "xcodebuild -showBuildSettings #{xcodebuild_parameters.join(' ')}"
+      else
+        command = "xcodebuild clean -showBuildSettings #{xcodebuild_parameters.join(' ')}"
+      end
       command += " 2> /dev/null" if xcodebuild_suppress_stderr
       command
     end

fastlane_core/spec/project_spec.rb

@@ -296,10 +296,21 @@ def within_a_temp_dir
     end
 
     describe "build_settings() can handle empty lines" do
-      it "SUPPORTED_PLATFORMS should be iphonesimulator iphoneos" do
+      it "SUPPORTED_PLATFORMS should be iphonesimulator iphoneos on Xcode >= 8.3" do
         options = { project: "./fastlane_core/spec/fixtures/projects/Example.xcodeproj" }
         @project = FastlaneCore::Project.new(options, xcodebuild_list_silent: true, xcodebuild_suppress_stderr: true)
-        expect(FastlaneCore::Project).to receive(:run_command).with("xcodebuild clean -showBuildSettings -project ./fastlane_core/spec/fixtures/projects/Example.xcodeproj 2> /dev/null", { timeout: 10, retries: 3, print: false }).and_return(File.read("./fastlane_core/spec/fixtures/projects/build_settings_with_toolchains"))
+        expect(FastlaneCore::Helper).to receive(:xcode_at_least?).and_return(true)
+        command = "xcodebuild -showBuildSettings -project ./fastlane_core/spec/fixtures/projects/Example.xcodeproj 2> /dev/null"
+        expect(FastlaneCore::Project).to receive(:run_command).with(command.to_s, { timeout: 10, retries: 3, print: false }).and_return(File.read("./fastlane_core/spec/fixtures/projects/build_settings_with_toolchains"))
+        expect(@project.build_settings(key: "SUPPORTED_PLATFORMS")).to eq("iphonesimulator iphoneos")
+      end
+
+      it "SUPPORTED_PLATFORMS should be iphonesimulator iphoneos on Xcode < 8.3" do
+        options = { project: "./fastlane_core/spec/fixtures/projects/Example.xcodeproj" }
+        @project = FastlaneCore::Project.new(options, xcodebuild_list_silent: true, xcodebuild_suppress_stderr: true)
+        expect(FastlaneCore::Helper).to receive(:xcode_at_least?).and_return(false)
+        command = "xcodebuild clean -showBuildSettings -project ./fastlane_core/spec/fixtures/projects/Example.xcodeproj 2> /dev/null"
+        expect(FastlaneCore::Project).to receive(:run_command).with(command.to_s, { timeout: 10, retries: 3, print: false }).and_return(File.read("./fastlane_core/spec/fixtures/projects/build_settings_with_toolchains"))
         expect(@project.build_settings(key: "SUPPORTED_PLATFORMS")).to eq("iphonesimulator iphoneos")
       end
     end

gym/lib/gym/xcode.rb

@@ -18,9 +18,7 @@ def pre_7?
       end
 
       def legacy_api_deprecated?
-        UI.user_error!("Unable to locate Xcode. Please make sure to have Xcode installed on your machine") if xcode_version.nil?
-        v = xcode_version
-        Gem::Version.new(v) >= Gem::Version.new('8.3.0')
+        FastlaneCore::Helper.xcode_at_least?('8.3')
       end
     end
   end