Revert "[flutter_tools] Dump backtrace on ios app startup timeout (#101610)" (#101761)

This reverts commit 2978b59.

Author: christopherfujino

packages/flutter_tools/lib/src/ios/devices.dart

@@ -434,7 +434,6 @@ class IOSDevice extends Device {
       _logger.printTrace('Application launched on the device. Waiting for observatory url.');
       final Timer timer = Timer(discoveryTimeout ?? const Duration(seconds: 30), () {
         _logger.printError('iOS Observatory not discovered after 30 seconds. This is taking much longer than expected...');
-        iosDeployDebugger?.pauseDumpBacktraceResume();
       });
       final Uri? localUri = await observatoryDiscovery?.uri;
       timer.cancel();

packages/flutter_tools/lib/src/ios/ios_deploy.dart

@@ -296,23 +296,12 @@ class IOSDeployDebugger {
   // (lldb) Process 6152 detached
   static final RegExp _lldbProcessDetached = RegExp(r'Process \d* detached');
 
-  // (lldb) Process 6152 resuming
-  static final RegExp _lldbProcessResuming = RegExp(r'Process \d+ resuming');
-
   // Send signal to stop (pause) the app. Used before a backtrace dump.
   static const String _signalStop = 'process signal SIGSTOP';
 
-  static const String _processResume = 'process continue';
-  static const String _processInterrupt = 'process interrupt';
-
   // Print backtrace for all threads while app is stopped.
   static const String _backTraceAll = 'thread backtrace all';
 
-  /// If this is non-null, then the app process is paused and awaiting backtrace logging.
-  ///
-  /// The future should be completed once the backtraces are logged.
-  Completer<void>? _processResumeCompleter;
-
   /// Launch the app on the device, and attach the debugger.
   ///
   /// Returns whether or not the debugger successfully attached.
@@ -330,6 +319,7 @@ class IOSDeployDebugger {
           .transform<String>(const LineSplitter())
           .listen((String line) {
         _monitorIOSDeployFailure(line, _logger);
+
         // (lldb)     run
         // success
         // 2020-09-15 13:42:25.185474-0700 Runner[477:181141] flutter: The Dart VM service is listening on http://127.0.0.1:57782/
@@ -360,26 +350,16 @@ class IOSDeployDebugger {
           // Even though we're not "detached", just stopped, mark as detached so the backtrace
           // is only show in verbose.
           _debuggerState = _IOSDeployDebuggerState.detached;
-
-          // If we paused the app and are waiting to resume it, complete the completer
-          final Completer<void>? processResumeCompleter = _processResumeCompleter;
-          if (processResumeCompleter != null) {
-            _processResumeCompleter = null;
-            processResumeCompleter.complete();
-          }
           return;
         }
 
         if (line.contains('PROCESS_STOPPED') || _lldbProcessStopped.hasMatch(line)) {
           // The app has been stopped. Dump the backtrace, and detach.
           _logger.printTrace(line);
           _iosDeployProcess?.stdin.writeln(_backTraceAll);
-          if (_processResumeCompleter == null) {
-            detach();
-          }
+          detach();
           return;
         }
-
         if (line.contains('PROCESS_EXITED') || _lldbProcessExit.hasMatch(line)) {
           // The app exited or crashed, so exit. Continue passing debugging
           // messages to the log reader until it exits to capture crash dumps.
@@ -394,13 +374,6 @@ class IOSDeployDebugger {
           return;
         }
 
-        if (_lldbProcessResuming.hasMatch(line)) {
-          _logger.printTrace(line);
-          // we marked this detached when we received [_backTraceAll]
-          _debuggerState = _IOSDeployDebuggerState.attached;
-          return;
-        }
-
         if (_debuggerState != _IOSDeployDebuggerState.attached) {
           _logger.printTrace(line);
           return;
@@ -460,28 +433,11 @@ class IOSDeployDebugger {
     return success;
   }
 
-  /// Pause app, dump backtrace for debugging, and resume.
-  Future<void> pauseDumpBacktraceResume() async {
-    if (!debuggerAttached) {
-      return;
-    }
-    final Completer<void> completer = Completer<void>();
-    _processResumeCompleter = completer;
-    try {
-      // Stop the app, which will prompt the backtrace to be printed for all threads in the stdoutSubscription handler.
-      _iosDeployProcess?.stdin.writeln(_processInterrupt);
-    } on SocketException catch (error) {
-      _logger.printTrace('Could not stop app from debugger: $error');
-    }
-    // wait for backtrace to be dumped
-    await completer.future;
-    _iosDeployProcess?.stdin.writeln(_processResume);
-  }
-
   Future<void> stopAndDumpBacktrace() async {
     if (!debuggerAttached) {
       return;
     }
+
     try {
       // Stop the app, which will prompt the backtrace to be printed for all threads in the stdoutSubscription handler.
       _iosDeployProcess?.stdin.writeln(_signalStop);

packages/flutter_tools/test/general.shard/ios/ios_deploy_test.dart

@@ -330,71 +330,6 @@ void main () {
         'process detach',
       ]);
     });
-
-    testWithoutContext('pause with backtrace', () async {
-      final StreamController<List<int>> stdin = StreamController<List<int>>();
-      final Stream<String> stdinStream = stdin.stream.transform<String>(const Utf8Decoder());
-      const String stdout = '''
-(lldb)     run
-success
-Log on attach
-(lldb) Process 6156 stopped
-* thread #1, stop reason = Assertion failed:
-thread backtrace all
-process continue
-* thread #1, stop reason = signal SIGSTOP
-  * frame #0: 0x0000000102eaee80 dyld`dyld3::MachOFile::read_uleb128(Diagnostics&, unsigned char const*&, unsigned char const*) + 36
-    frame #1: 0x0000000102eabbd4 dyld`dyld3::MachOLoaded::trieWalk(Diagnostics&, unsigned char const*, unsigned char const*, char const*) + 332
-    frame #2: 0x0000000102eaa078 dyld`DyldSharedCache::hasImagePath(char const*, unsigned int&) const + 144
-    frame #3: 0x0000000102eaa13c dyld`DyldSharedCache::hasNonOverridablePath(char const*) const + 44
-    frame #4: 0x0000000102ebc404 dyld`dyld3::closure::ClosureBuilder::findImage(char const*, dyld3::closure::ClosureBuilder::LoadedImageChain const&, dyld3::closure::ClosureBuilder::BuilderLoadedImage*&, dyld3::closure::ClosureBuilder::LinkageType, unsigned int, bool) +
-
-    frame #5: 0x0000000102ebd974 dyld`invocation function for block in dyld3::closure::ClosureBuilder::recursiveLoadDependents(dyld3::closure::ClosureBuilder::LoadedImageChain&, bool) + 136
-    frame #6: 0x0000000102eae1b0 dyld`invocation function for block in dyld3::MachOFile::forEachDependentDylib(void (char const*, bool, bool, bool, unsigned int, unsigned int, bool&) block_pointer) const + 136
-    frame #7: 0x0000000102eadc38 dyld`dyld3::MachOFile::forEachLoadCommand(Diagnostics&, void (load_command const*, bool&) block_pointer) const + 168
-    frame #8: 0x0000000102eae108 dyld`dyld3::MachOFile::forEachDependentDylib(void (char const*, bool, bool, bool, unsigned int, unsigned int, bool&) block_pointer) const + 116
-    frame #9: 0x0000000102ebd80c dyld`dyld3::closure::ClosureBuilder::recursiveLoadDependents(dyld3::closure::ClosureBuilder::LoadedImageChain&, bool) + 164
-    frame #10: 0x0000000102ebd8a8 dyld`dyld3::closure::ClosureBuilder::recursiveLoadDependents(dyld3::closure::ClosureBuilder::LoadedImageChain&, bool) + 320
-    frame #11: 0x0000000102ebd8a8 dyld`dyld3::closure::ClosureBuilder::recursiveLoadDependents(dyld3::closure::ClosureBuilder::LoadedImageChain&, bool) + 320
-    frame #12: 0x0000000102ebd8a8 dyld`dyld3::closure::ClosureBuilder::recursiveLoadDependents(dyld3::closure::ClosureBuilder::LoadedImageChain&, bool) + 320
-    frame #13: 0x0000000102ebd8a8 dyld`dyld3::closure::ClosureBuilder::recursiveLoadDependents(dyld3::closure::ClosureBuilder::LoadedImageChain&, bool) + 320
-    frame #14: 0x0000000102ebd8a8 dyld`dyld3::closure::ClosureBuilder::recursiveLoadDependents(dyld3::closure::ClosureBuilder::LoadedImageChain&, bool) + 320
-    frame #15: 0x0000000102ebd8a8 dyld`dyld3::closure::ClosureBuilder::recursiveLoadDependents(dyld3::closure::ClosureBuilder::LoadedImageChain&, bool) + 320
-    frame #16: 0x0000000102ec7638 dyld`dyld3::closure::ClosureBuilder::makeLaunchClosure(dyld3::closure::LoadedFileInfo const&, bool) + 752
-    frame #17: 0x0000000102e8fcf0 dyld`dyld::buildLaunchClosure(unsigned char const*, dyld3::closure::LoadedFileInfo const&, char const**) + 344
-    frame #18: 0x0000000102e8e938 dyld`dyld::_main(macho_header const*, unsigned long, int, char const**, char const**, char const**, unsigned long*) + 2876
-    frame #19: 0x0000000102e8922c dyld`dyldbootstrap::start(dyld3::MachOLoaded const*, int, char const**, dyld3::MachOLoaded const*, unsigned long*) + 432
-    frame #20: 0x0000000102e89038 dyld`_dyld_start + 56
-''';
-      final BufferLogger logger = BufferLogger.test();
-      final FakeProcessManager processManager = FakeProcessManager.list(<FakeCommand>[
-        FakeCommand(
-          command: const <String>[
-            'ios-deploy',
-          ],
-          stdout: stdout,
-          stdin: IOSink(stdin.sink),
-        ),
-      ]);
-      final IOSDeployDebugger iosDeployDebugger = IOSDeployDebugger.test(
-        processManager: processManager,
-        logger: logger,
-      );
-      await iosDeployDebugger.launchAndAttach();
-      await iosDeployDebugger.pauseDumpBacktraceResume();
-      // verify stacktrace was logged to trace
-      expect(
-        logger.traceText,
-        contains(
-          'frame #0: 0x0000000102eaee80 dyld`dyld3::MachOFile::read_uleb128(Diagnostics&, unsigned char const*&, unsigned char const*) + 36',
-        ),
-      );
-      expect(await stdinStream.take(3).toList(), <String>[
-        'thread backtrace all',
-        '\n',
-        'process detach',
-      ]);
-    });
   });
 
   group('IOSDeploy.uninstallApp', () {

packages/flutter_tools/test/general.shard/ios/ios_device_start_prebuilt_test.dart

@@ -5,12 +5,10 @@
 // @dart = 2.8
 
 import 'dart:async';
-import 'dart:convert';
 
 import 'package:file/memory.dart';
 import 'package:flutter_tools/src/artifacts.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
-import 'package:flutter_tools/src/base/io.dart';
 import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/build_info.dart';
@@ -66,35 +64,26 @@ const FakeCommand kLaunchDebugCommand = FakeCommand(command: <String>[
 });
 
 // The command used to actually launch the app and attach the debugger with args in debug.
-FakeCommand attachDebuggerCommand({
-  IOSink stdin,
-  Completer<void>/*?*/ completer,
-}) {
-  return FakeCommand(
-    command: const <String>[
-      'script',
-      '-t',
-      '0',
-      '/dev/null',
-      'HostArtifact.iosDeploy',
-      '--id',
-      '123',
-      '--bundle',
-      '/',
-      '--debug',
-      '--no-wifi',
-      '--args',
-      '--enable-dart-profiling --disable-service-auth-codes --enable-checked-mode --verify-entry-points',
-    ],
-    completer: completer,
-    environment: const <String, String>{
-      'PATH': '/usr/bin:null',
-      'DYLD_LIBRARY_PATH': '/path/to/libraries',
-    },
-    stdout: '(lldb)     run\nsuccess',
-    stdin: stdin,
-  );
-}
+const FakeCommand kAttachDebuggerCommand = FakeCommand(command: <String>[
+  'script',
+  '-t',
+  '0',
+  '/dev/null',
+  'HostArtifact.iosDeploy',
+  '--id',
+  '123',
+  '--bundle',
+  '/',
+  '--debug',
+  '--no-wifi',
+  '--args',
+  '--enable-dart-profiling --disable-service-auth-codes --enable-checked-mode --verify-entry-points'
+], environment: <String, String>{
+  'PATH': '/usr/bin:null',
+  'DYLD_LIBRARY_PATH': '/path/to/libraries',
+},
+stdout: '(lldb)     run\nsuccess',
+);
 
 void main() {
   testWithoutContext('disposing device disposes the portForwarder and logReader', () async {
@@ -119,7 +108,7 @@ void main() {
   testWithoutContext('IOSDevice.startApp attaches in debug mode via log reading on iOS 13+', () async {
     final FileSystem fileSystem = MemoryFileSystem.test();
     final FakeProcessManager processManager = FakeProcessManager.list(<FakeCommand>[
-      attachDebuggerCommand(),
+      kAttachDebuggerCommand,
     ]);
     final IOSDevice device = setUpIOSDevice(
       processManager: processManager,
@@ -194,10 +183,8 @@ void main() {
   testWithoutContext('IOSDevice.startApp prints warning message if discovery takes longer than configured timeout', () async {
     final FileSystem fileSystem = MemoryFileSystem.test();
     final BufferLogger logger = BufferLogger.test();
-    final CompleterIOSink stdin = CompleterIOSink();
-    final Completer<void> completer = Completer<void>();
     final FakeProcessManager processManager = FakeProcessManager.list(<FakeCommand>[
-      attachDebuggerCommand(stdin: stdin, completer: completer),
+      kAttachDebuggerCommand,
     ]);
     final IOSDevice device = setUpIOSDevice(
       processManager: processManager,
@@ -216,8 +203,11 @@ void main() {
     device.setLogReader(iosApp, deviceLogReader);
 
     // Start writing messages to the log reader.
-    deviceLogReader.addLine('Foo');
-    deviceLogReader.addLine('The Dart VM service is listening on http://127.0.0.1:456');
+    Timer.run(() async {
+      await Future<void>.delayed(const Duration(milliseconds: 1));
+      deviceLogReader.addLine('Foo');
+      deviceLogReader.addLine('The Dart VM service is listening on http://127.0.0.1:456');
+    });
 
     final LaunchResult launchResult = await device.startApp(iosApp,
       prebuiltApplication: true,
@@ -230,9 +220,6 @@ void main() {
     expect(launchResult.hasObservatory, true);
     expect(await device.stopApp(iosApp), false);
     expect(logger.errorText, contains('iOS Observatory not discovered after 30 seconds. This is taking much longer than expected...'));
-    expect(utf8.decoder.convert(stdin.writes.first), contains('process interrupt'));
-    completer.complete();
-    expect(processManager, hasNoRemainingExpectations);
   });
 
   testWithoutContext('IOSDevice.startApp succeeds in release mode', () async {