[flutter_tools] catch ProcessException and throw ToolExit during upgrade (#55759)

packages/flutter_tools/lib/src/commands/upgrade.dart

@@ -137,7 +137,7 @@ class UpgradeCommandRunner {
     }
     recordState(flutterVersion);
     await upgradeChannel(flutterVersion);
-    await attemptReset(flutterVersion, upstreamRevision);
+    await attemptReset(upstreamRevision);
     if (!testFlow) {
       await flutterUpgradeContinue();
     }
@@ -243,14 +243,15 @@ class UpgradeCommandRunner {
   /// This is a reset instead of fast forward because if we are on a release
   /// branch with cherry picks, there may not be a direct fast-forward route
   /// to the next release.
-  Future<void> attemptReset(FlutterVersion oldFlutterVersion, String newRevision) async {
-    final RunResult result = await processUtils.run(
-      <String>['git', 'reset', '--hard', newRevision],
-      throwOnError: true,
-      workingDirectory: workingDirectory,
-    );
-    if (result.exitCode != 0) {
-      throwToolExit(null, exitCode: result.exitCode);
+  Future<void> attemptReset(String newRevision) async {
+    try {
+      await processUtils.run(
+        <String>['git', 'reset', '--hard', newRevision],
+        throwOnError: true,
+        workingDirectory: workingDirectory,
+      );
+    } on ProcessException catch (e) {
+      throwToolExit(e.message, exitCode: e.errorCode);
     }
   }
 

packages/flutter_tools/test/commands.shard/permeable/upgrade_test.dart

@@ -186,6 +186,26 @@ void main() {
       Platform: () => fakePlatform,
     });
 
+    testUsingContext('git exception during attemptReset throwsToolExit', () async {
+      const String revision = 'abc123';
+      const String errorMessage = 'fatal: Could not parse object ´$revision´';
+      when(processManager.run(
+        <String>['git', 'reset', '--hard', revision]
+      )).thenThrow(const ProcessException(
+        'git',
+        <String>['reset', '--hard', revision],
+        errorMessage,
+      ));
+
+      expect(
+        () async => await realCommandRunner.attemptReset(revision),
+        throwsToolExit(message: errorMessage),
+      );
+    }, overrides: <Type, Generator>{
+      ProcessManager: () => processManager,
+      Platform: () => fakePlatform,
+    });
+
     testUsingContext('flutterUpgradeContinue passes env variables to child process', () async {
       await realCommandRunner.flutterUpgradeContinue();
 
@@ -315,7 +335,7 @@ class FakeUpgradeCommandRunner extends UpgradeCommandRunner {
   Future<void> upgradeChannel(FlutterVersion flutterVersion) async {}
 
   @override
-  Future<bool> attemptReset(FlutterVersion flutterVersion, String newRevision) async => alreadyUpToDate;
+  Future<void> attemptReset(String newRevision) async {}
 
   @override
   Future<void> precacheArtifacts() async {}