Suppress upgrade message with --machine (#49408)

packages/flutter_tools/lib/src/runner/flutter_command_runner.dart

@@ -309,7 +309,8 @@ class FlutterCommandRunner extends CommandRunner<void> {
           globals.printError('Please ensure you have permissions in the artifact cache directory.');
           throwToolExit('Failed to write the version file');
         }
-        if (topLevelResults.command?.name != 'upgrade' && topLevelResults['version-check'] as bool) {
+        final bool machineFlag = topLevelResults['machine'] as bool;
+        if (topLevelResults.command?.name != 'upgrade' && topLevelResults['version-check'] as bool && !machineFlag) {
           await FlutterVersion.instance.checkFlutterVersionFreshness();
         }
 
@@ -323,7 +324,7 @@ class FlutterCommandRunner extends CommandRunner<void> {
         if (topLevelResults['version'] as bool) {
           flutterUsage.sendCommand('version');
           String status;
-          if (topLevelResults['machine'] as bool) {
+          if (machineFlag) {
             status = const JsonEncoder.withIndent('  ').convert(FlutterVersion.instance.toJson());
           } else {
             status = FlutterVersion.instance.toString();
@@ -332,7 +333,7 @@ class FlutterCommandRunner extends CommandRunner<void> {
           return;
         }
 
-        if (topLevelResults['machine'] as bool) {
+        if (machineFlag) {
           throwToolExit('The --machine flag is only valid with the --version flag.', exitCode: 2);
         }
         await super.runCommand(topLevelResults);

packages/flutter_tools/test/general.shard/runner/flutter_command_runner_test.dart

@@ -72,6 +72,22 @@ void main() {
         Platform: () => platform,
       }, initializeFlutterRoot: false);
 
+      testUsingContext('does not check that Flutter installation is up-to-date with --machine flag', () async {
+        final MockFlutterVersion version = FlutterVersion.instance as MockFlutterVersion;
+        bool versionChecked = false;
+        when(version.checkFlutterVersionFreshness()).thenAnswer((_) async {
+          versionChecked = true;
+        });
+
+        await runner.run(<String>['dummy', '--machine', '--version']);
+
+        expect(versionChecked, isFalse);
+      }, overrides: <Type, Generator>{
+        FileSystem: () => fs,
+        ProcessManager: () => FakeProcessManager.any(),
+        Platform: () => platform,
+      }, initializeFlutterRoot: false);
+
       testUsingContext('throw tool exit if the version file cannot be written', () async {
         final MockFlutterVersion version = FlutterVersion.instance as MockFlutterVersion;
         when(version.ensureVersionFile()).thenThrow(const FileSystemException());