[action][spm] add simulator flag for swift compiler

fastlane/lib/fastlane/actions/spm.rb

@@ -11,11 +11,14 @@ def self.run(params)
         cmd << "--disable-sandbox" if params[:disable_sandbox]
         cmd << "--verbose" if params[:verbose]
         if params[:simulator]
+          _simulator_platform = simulator_platform(simulator: params[:simulator], simulator_arch: params[:simulator_arch])
+          _simulator_sdk = simulator_sdk(simulator: params[:simulator])
+          _simulator_sdk_suffix = simulator_sdk_suffix(simulator: params[:simulator])
           simulator_flags = [
             "-Xswiftc", "-sdk",
             "-Xswiftc", "$(xcrun --sdk #{params[:simulator]} --show-sdk-path)",
             "-Xswiftc", "-target",
-            "-Xswiftc", "#{params[:simulator_arch] || "arm64"}-apple-#{params[:simulator] == "iphonesimulator" ? 'ios' : 'macosx'}$(xcrun --sdk #{params[:simulator]} --show-sdk-version | cut -d '.' -f 1)#{"-simulator" if params[:simulator] == "iphonesimulator"}"
+            "-Xswiftc", "#{_simulator_platform}#{_simulator_sdk}#{_simulator_sdk_suffix}"
           ]
           cmd += simulator_flags
         end
@@ -113,11 +116,12 @@ def self.available_options
                                        end),
           FastlaneCore::ConfigItem.new(key: :simulator_arch,
                                        env_name: "FL_SPM_SIMULATOR_ARCH",
-                                       description: "Specifies the architecture of the simulator to pass for Swift Compiler (one of: #{valid_architectures.join(', ')}), requires simulator to be specified also",
+                                       description: "Specifies the architecture of the simulator to pass for Swift Compiler (one of: #{valid_architectures.join(', ')}). Requires the simulator option to be specified also, otherwise, it's ignored",
                                        type: String,
-                                       optional: true,
+                                       optional: false,
+                                       default_value: "arm64",
                                        verify_block: proc do |value|
-                                         UI.user_error!("Please pass a valid simulator architecrure. Use one of the following: #{valid_architectures.join(', ')}") unless valid_architectures.include?(value)
+                                         UI.user_error!("Please pass a valid simulator architecture. Use one of the following: #{valid_architectures.join(', ')}") unless valid_architectures.include?(value)
                                        end)
         ]
       end
@@ -141,6 +145,13 @@ def self.example_code
           'spm(
             command: "generate-xcodeproj",
             xcconfig: "Package.xcconfig"
+          )',
+          'spm(
+            simulator: "iphonesimulator"
+          )',
+          'spm(
+            simulator: "macosx",
+            simulator_arch: "arm64"
           )'
         ]
       end
@@ -172,6 +183,20 @@ def self.valid_simulators
       def self.valid_architectures
         %w(x86_64 arm64)
       end
+
+      def self.simulator_platform(params)
+        platform_suffix = "#{params[:simulator] == "iphonesimulator" ? 'ios' : 'macosx'}"
+        "#{params[:simulator_arch]}-apple-#{platform_suffix}"
+      end
+
+      def self.simulator_sdk(params)
+        "$(xcrun --sdk #{params[:simulator]} --show-sdk-version | cut -d '.' -f 1)"
+      end
+
+      def self.simulator_sdk_suffix(params)
+        return "" unless params[:simulator] == "iphonesimulator"
+        "-simulator"
+      end
     end
   end
 end