From 8930e9b89218b6aec80d283c111f72d00a4ac456 Mon Sep 17 00:00:00 2001
From: Jenn Magder <magder@google.com>
Date: Fri, 8 Oct 2021 13:08:04 -0700
Subject: [PATCH] Catch FormatException parsing XCDevice._getAllDevices
 (#90967)

---
 packages/flutter_tools/lib/src/macos/xcdevice.dart  | 13 ++++++++++---
 .../test/general.shard/macos/xcode_test.dart        | 13 +++++++++++++
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/packages/flutter_tools/lib/src/macos/xcdevice.dart b/packages/flutter_tools/lib/src/macos/xcdevice.dart
index 884f3a78d97..00f8c67b3cc 100644
--- a/packages/flutter_tools/lib/src/macos/xcdevice.dart
+++ b/packages/flutter_tools/lib/src/macos/xcdevice.dart
@@ -112,9 +112,16 @@ class XCDevice {
         throwOnError: true,
       );
       if (result.exitCode == 0) {
-        final List<dynamic> listResults = json.decode(result.stdout) as List<dynamic>;
-        _cachedListResults = listResults;
-        return listResults;
+        final String listOutput = result.stdout;
+        try {
+          final List<dynamic> listResults = json.decode(listOutput) as List<dynamic>;
+          _cachedListResults = listResults;
+          return listResults;
+        } on FormatException {
+          // xcdevice logs errors and crashes to stdout.
+          _logger.printError('xcdevice returned non-JSON response: $listOutput');
+          return null;
+        }
       }
       _logger.printTrace('xcdevice returned an error:\n${result.stderr}');
     } on ProcessException catch (exception) {
diff --git a/packages/flutter_tools/test/general.shard/macos/xcode_test.dart b/packages/flutter_tools/test/general.shard/macos/xcode_test.dart
index 4b6506690da..430ac0709af 100644
--- a/packages/flutter_tools/test/general.shard/macos/xcode_test.dart
+++ b/packages/flutter_tools/test/general.shard/macos/xcode_test.dart
@@ -680,6 +680,19 @@ void main() {
         }, overrides: <Type, Generator>{
           Platform: () => macPlatform,
         });
+
+        testUsingContext('handles bad output',()  async {
+          fakeProcessManager.addCommand(const FakeCommand(
+            command: <String>['xcrun', 'xcdevice', 'list', '--timeout', '2'],
+            stdout: 'Something bad happened, not JSON',
+          ));
+
+          final List<IOSDevice> devices = await xcdevice.getAvailableIOSDevices();
+          expect(devices, isEmpty);
+          expect(logger.errorText, contains('xcdevice returned non-JSON response'));
+        }, overrides: <Type, Generator>{
+          Platform: () => macPlatform,
+        });
       });
 
       group('diagnostics', () {