after upgrade to 0.56.0-rc.2 production build is crashing

[eshikerya]

• Review the documentation: https://facebook.github.io/react-native
• Search for existing issues: https://github.com/facebook/react-native/issues
• Use the latest React Native release: https://github.com/facebook/react-native/releases

Environment

React Native Environment Info:
    System:
      OS: macOS High Sierra 10.13.6
      CPU: x64 Intel(R) Core(TM) i5-5257U CPU @ 2.70GHz
      Memory: 881.80 MB / 16.00 GB
      Shell: 3.2.57 - /bin/bash
    Binaries:
      Node: 9.11.1 - ~/.nvm/versions/node/v9.11.1/bin/node
      Yarn: 1.7.0 - ~/.yarn/bin/yarn
      npm: 5.6.0 - ~/.nvm/versions/node/v9.11.1/bin/npm
      Watchman: 4.9.0 - /usr/local/bin/watchman
    SDKs:
      iOS SDK:
        Platforms: iOS 11.4, macOS 10.13, tvOS 11.4, watchOS 4.3
      Android SDK:
        Build Tools: 23.0.1, 25.0.2, 25.0.3, 26.0.1, 27.0.1, 27.0.3
        API Levels: 23, 24, 25, 26, 27
    IDEs:
      Android Studio: 3.1 AI-173.4720617
      Xcode: 9.4.1/9F2000 - /usr/bin/xcodebuild
    npmPackages:
      react: 16.3.2 => 16.3.2 
      react-native: 0.56.0-rc.2 => 0.56.0-rc.2 

Description

the project normally functioning on 0.55.4 after react-native-git-upgrade 0.56.0-rc.2working in simulator, but crashing on start on real device with production build. I removed everything, but none is helping, app name is CasualPM, here is crash report:

Details

Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Exception Note: EXC_CORPSE_NOTIFY Triggered by Thread: 0

Application Specific Information:
abort() called

Filtered syslog:
None found

Last Exception Backtrace:
0 CoreFoundation 0x1e4baf960 __exceptionPreprocess + 152
1 libobjc.A.dylib 0x1e3e6052c objc_exception_throw + 55
2 CasualPM 0x104926e88 hidden#1135 + 192136 (_hidden#2451:132)
3 CasualPM 0x104912d28 hidden#1136 + 109864 (_hidden#1437:854)
4 libdispatch.dylib 0x1e459a8a8 _dispatch_call_block_and_release + 23
5 libdispatch.dylib 0x1e459a85c _dispatch_client_callout + 15
6 libdispatch.dylib 0x1e45a8c28 _dispatch_main_queue_callback_4CF$VARIANT$mp + 1063
7 CoreFoundation 0x1e4b61748 CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE + 11
8 CoreFoundation 0x1e4b5f3e0 __CFRunLoopRun + 1975
9 CoreFoundation 0x1e4a98430 CFRunLoopRunSpecific + 435
10 Foundation 0x1e5519e84 -[NSRunLoop+ 32388 (NSRunLoop) runMode:beforeDate:] + 299
11 Foundation 0x1e5519cf4 -[NSRunLoop+ 31988 (NSRunLoop) runUntilDate:] + 87
12 CasualPM 0x104a203f4 hidden#14662 + 1213428 (_hidden#14672:30)
13 CasualPM 0x1048fc9a8 hidden#2 + 18856 (_hidden#18:51)
14 UIKitCore 0x2108cc350 -[UIApplication _handleDelegateCallbacksWithOptions:isSuspended:restoreState:] + 407
15 UIKitCore 0x2108cda8c -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 3339
16 UIKitCore 0x2108d33c8 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1775
17 UIKitCore 0x2110f200c __111-[__UICanvasLifecycleMonitor_Compatability _scheduleFirstCommitForScene:transition:firstActivation:completion:]_block_invoke + 783
18 UIKitCore 0x2110eec9c +[_UICanvas _enqueuePostSettingUpdateTransactionBlock:] + 159
19 UIKitCore 0x2110f1c88 -[__UICanvasLifecycleMonitor_Compatability _scheduleFirstCommitForScene:transition:firstActivation:completion:] + 239
20 UIKitCore 0x2110f24c8 -[__UICanvasLifecycleMonitor_Compatability activateEventsOnly:withContext:completion:] + 723
21 UIKitCore 0x2110b3084 __82-[_UIApplicationCanvas _transitionLifecycleStateWithTransitionContext:completion:]_block_invoke + 295
22 UIKitCore 0x2110b2f0c -[_UIApplicationCanvas _transitionLifecycleStateWithTransitionContext:completion:] + 431
23 UIKitCore 0x2110f3f8c __125-[_UICanvasLifecycleSettingsDiffAction performActionsForCanvas:withUpdatedScene:settingsDiff:fromSettings:transitionContext:]_block_invoke + 219
24 UIKitCore 0x2110f4a7c _performActionsWithDelayForTransitionContext + 111
25 UIKitCore 0x2110f3e44 -[_UICanvasLifecycleSettingsDiffAction performActionsForCanvas:withUpdatedScene:settingsDiff:fromSettings:transitionContext:] + 247
26 UIKitCore 0x2110ee348 -[_UICanvas scene:didUpdateWithDiff:transitionContext:completion:] + 367
27 UIKitCore 0x2108d1854 -[UIApplication workspace:didCreateScene:withTransitionContext:completion:] + 539
28 UIKitCore 0x210903704 -[UIApplicationSceneClientAgent scene:didInitializeWithEvent:completion:] + 363
29 FrontBoardServices 0x1e75fafa0 -[FBSSceneImpl _didCreateWithTransitionContext:completion:] + 443
30 FrontBoardServices 0x1e7605d6c __56-[FBSWorkspace client:handleCreateScene:withCompletion:]_block_invoke_2 + 259
31 FrontBoardServices 0x1e7605460 __40-[FBSWorkspace _performDelegateCallOut:]_block_invoke + 63
32 libdispatch.dylib 0x1e459a85c _dispatch_client_callout + 15
33 libdispatch.dylib 0x1e459fe90 _dispatch_block_invoke_direct$VARIANT$mp + 223
34 FrontBoardServices 0x1e7639a14 FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK + 39
35 FrontBoardServices 0x1e76396a0 -[FBSSerialQueue _performNext] + 415
36 FrontBoardServices 0x1e7639cbc -[FBSSerialQueue _performNextFromRunLoopSource] + 55
37 CoreFoundation 0x1e4b61b4c CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION + 23
38 CoreFoundation 0x1e4b61acc __CFRunLoopDoSource0 + 87
39 CoreFoundation 0x1e4b613a4 __CFRunLoopDoSources0 + 175
40 CoreFoundation 0x1e4b5f044 __CFRunLoopRun + 1051
41 CoreFoundation 0x1e4a98430 CFRunLoopRunSpecific + 435
42 GraphicsServices 0x1e6dc7548 GSEventRunModal + 99
43 UIKitCore 0x2108d51e0 UIApplicationMain + 211
44 CasualPM 0x1048fca68 main + 19048 (_hidden#21:14)
45 libdyld.dylib 0x1e460cfa8 start + 3

Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0 libsystem_kernel.dylib 0x00000001e475867c __pthread_kill + 8
1 libsystem_pthread.dylib 0x00000001e47d7520 pthread_kill$VARIANT$mp + 384
2 libsystem_c.dylib 0x00000001e46bab80 abort + 140
3 libc++abi.dylib 0x00000001e3e43ea8 abort_message + 132
4 libc++abi.dylib 0x00000001e3e4406c default_terminate_handler+ 8300 () + 316
5 libobjc.A.dylib 0x00000001e3e60940 _objc_terminate+ 35136 () + 124
6 CasualPM 0x0000000104a06fd8 hidden#13772 + 1109976 (_hidden#13780:179)
7 libc++abi.dylib 0x00000001e3e50ff0 std::__terminate(void (*)+ 61424 ()) + 16
8 libc++abi.dylib 0x00000001e3e51088 std::terminate+ 61576 () + 88
9 libdispatch.dylib 0x00000001e459a870 _dispatch_client_callout + 36
10 libdispatch.dylib 0x00000001e45a8c28 _dispatch_main_queue_callback_4CF$VARIANT$mp + 1064
11 CoreFoundation 0x00000001e4b61748 CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE + 12
12 CoreFoundation 0x00000001e4b5f3e0 __CFRunLoopRun + 1976
13 CoreFoundation 0x00000001e4a98430 CFRunLoopRunSpecific + 436
14 Foundation 0x00000001e5519e84 -[NSRunLoop+ 32388 (NSRunLoop) runMode:beforeDate:] + 300
15 Foundation 0x00000001e5519cf4 -[NSRunLoop+ 31988 (NSRunLoop) runUntilDate:] + 88
16 CasualPM 0x0000000104a203f4 hidden#14662 + 1213428 (_hidden#14672:30)
17 CasualPM 0x00000001048fc9a8 hidden#2 + 18856 (_hidden#18:55)
18 UIKitCore 0x00000002108cc350 -[UIApplication _handleDelegateCallbacksWithOptions:isSuspended:restoreState:] + 408
19 UIKitCore 0x00000002108cda8c -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 3340
20 UIKitCore 0x00000002108d33c8 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1776
21 UIKitCore 0x00000002110f200c __111-[__UICanvasLifecycleMonitor_Compatability _scheduleFirstCommitForScene:transition:firstActivation:completion:]_block_invoke + 784
22 UIKitCore 0x00000002110eec9c +[_UICanvas _enqueuePostSettingUpdateTransactionBlock:] + 160
23 UIKitCore 0x00000002110f1c88 -[__UICanvasLifecycleMonitor_Compatability _scheduleFirstCommitForScene:transition:firstActivation:completion:] + 240
24 UIKitCore 0x00000002110f24c8 -[__UICanvasLifecycleMonitor_Compatability activateEventsOnly:withContext:completion:] + 724
25 UIKitCore 0x00000002110b3084 __82-[_UIApplicationCanvas _transitionLifecycleStateWithTransitionContext:completion:]_block_invoke + 296
26 UIKitCore 0x00000002110b2f0c -[_UIApplicationCanvas _transitionLifecycleStateWithTransitionContext:completion:] + 432
27 UIKitCore 0x00000002110f3f8c __125-[_UICanvasLifecycleSettingsDiffAction performActionsForCanvas:withUpdatedScene:settingsDiff:fromSettings:transitionContext:]_block_invoke + 220
28 UIKitCore 0x00000002110f4a7c _performActionsWithDelayForTransitionContext + 112
29 UIKitCore 0x00000002110f3e44 -[_UICanvasLifecycleSettingsDiffAction performActionsForCanvas:withUpdatedScene:settingsDiff:fromSettings:transitionContext:] + 248
30 UIKitCore 0x00000002110ee348 -[_UICanvas scene:didUpdateWithDiff:transitionContext:completion:] + 368
31 UIKitCore 0x00000002108d1854 -[UIApplication workspace:didCreateScene:withTransitionContext:completion:] + 540
32 UIKitCore 0x0000000210903704 -[UIApplicationSceneClientAgent scene:didInitializeWithEvent:completion:] + 364
33 FrontBoardServices 0x00000001e75fafa0 -[FBSSceneImpl _didCreateWithTransitionContext:completion:] + 444
34 FrontBoardServices 0x00000001e7605d6c __56-[FBSWorkspace client:handleCreateScene:withCompletion:]_block_invoke_2 + 260
35 FrontBoardServices 0x00000001e7605460 __40-[FBSWorkspace _performDelegateCallOut:]_block_invoke + 64
36 libdispatch.dylib 0x00000001e459a85c _dispatch_client_callout + 16
37 libdispatch.dylib 0x00000001e459fe90 _dispatch_block_invoke_direct$VARIANT$mp + 224
38 FrontBoardServices 0x00000001e7639a14 FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK + 40
39 FrontBoardServices 0x00000001e76396a0 -[FBSSerialQueue _performNext] + 416
40 FrontBoardServices 0x00000001e7639cbc -[FBSSerialQueue _performNextFromRunLoopSource] + 56
41 CoreFoundation 0x00000001e4b61b4c CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION + 24
42 CoreFoundation 0x00000001e4b61acc __CFRunLoopDoSource0 + 88
43 CoreFoundation 0x00000001e4b613a4 __CFRunLoopDoSources0 + 176
44 CoreFoundation 0x00000001e4b5f044 __CFRunLoopRun + 1052
45 CoreFoundation 0x00000001e4a98430 CFRunLoopRunSpecific + 436
46 GraphicsServices 0x00000001e6dc7548 GSEventRunModal + 100
47 UIKitCore 0x00000002108d51e0 UIApplicationMain + 212
48 CasualPM 0x00000001048fca68 main + 19048 (_hidden#21:14)
49 libdyld.dylib 0x00000001e460cfa8 start + 4

Thread 1:
0 libsystem_pthread.dylib 0x00000001e47d5368 start_wqthread + 0

Thread 2:
0 libsystem_pthread.dylib 0x00000001e47d5368 start_wqthread + 0

Thread 3 name: Dispatch queue: Error API queue (QOS: UTILITY)
Thread 3:
0 libsystem_kernel.dylib 0x00000001e47589a0 __semwait_signal + 8
1 libsystem_c.dylib 0x00000001e4664c4c nanosleep + 212
2 Foundation 0x00000001e562a380 +[NSThread sleepForTimeInterval:] + 136
3 Foundation 0x00000001e5547468 -[__NSOperationInternal _start:] + 844
4 Foundation 0x00000001e5608fb4 __NSOQSchedule_f + 272
5 libdispatch.dylib 0x00000001e459a8a8 _dispatch_call_block_and_release + 24
6 libdispatch.dylib 0x00000001e459a85c _dispatch_client_callout + 16
7 libdispatch.dylib 0x00000001e459f8a0 _dispatch_continuation_pop$VARIANT$mp + 412
8 libdispatch.dylib 0x00000001e459ef54 _dispatch_async_redirect_invoke + 600
9 libdispatch.dylib 0x00000001e45abcd4 _dispatch_root_queue_drain + 372
10 libdispatch.dylib 0x00000001e45ac590 _dispatch_worker_thread2 + 128
11 libsystem_pthread.dylib 0x00000001e47d55c0 _pthread_wqthread + 480
12 libsystem_pthread.dylib 0x00000001e47d536c start_wqthread + 4

Thread 4:
0 libsystem_pthread.dylib 0x00000001e47d5368 start_wqthread + 0

Thread 5:
0 libsystem_pthread.dylib 0x00000001e47d5368 start_wqthread + 0

Thread 6 name: com.apple.uikit.eventfetch-thread
Thread 6:
0 libsystem_kernel.dylib 0x00000001e4736328 mach_msg_trap + 8
1 libsystem_kernel.dylib 0x00000001e47361a0 mach_msg + 72
2 CoreFoundation 0x00000001e4b61538 __CFRunLoopServiceMachPort + 236
3 CoreFoundation 0x00000001e4b5f1a8 __CFRunLoopRun + 1408
4 CoreFoundation 0x00000001e4a98430 CFRunLoopRunSpecific + 436
5 Foundation 0x00000001e5519e84 -[NSRunLoop+ 32388 (NSRunLoop) runMode:beforeDate:] + 300
6 Foundation 0x00000001e5519cf4 -[NSRunLoop+ 31988 (NSRunLoop) runUntilDate:] + 88
7 UIKitCore 0x000000021083274c -[UIEventFetcher threadMain] + 136
8 Foundation 0x00000001e562b064 NSThread__start + 1040
9 libsystem_pthread.dylib 0x00000001e47d65a4 _pthread_body + 132
10 libsystem_pthread.dylib 0x00000001e47d64f8 _pthread_start + 48
11 libsystem_pthread.dylib 0x00000001e47d5374 thread_start + 4

Thread 7 name: JavaScriptCore bmalloc scavenger
Thread 7:
0 libsystem_kernel.dylib 0x00000001e4758484 __psynch_cvwait + 8
1 libsystem_pthread.dylib 0x00000001e47d909c _pthread_cond_wait$VARIANT$mp + 636
2 libc++.1.dylib 0x00000001e3deef10 std::__1::condition_variable::__do_timed_wait+ 32528 (std::__1::unique_lockstd::__1::mutex&, std::__1::chrono::time_point<std::__1::chrono::system_clock, std::__1::chrono::duration<long long, std::__1::ratio<1l, 1000000000l> > >) + 96
3 JavaScriptCore 0x00000001ec84e28c std::__1::cv_status std::__1::condition_variable::wait_until<std::__1::chrono::steady_clock, std::__1::chrono::duration<long long, std::__1::ratio<1l, 1000000000l> > >+ 1565324 (std::__1::unique_lockstd::__1::mutex&, std::__1::chrono::time_point<std::__1::chrono::steady_clock, std::__1::chrono::duration<long long, std::__1::ratio<1l, 1000000000l> > > const&) + 124
4 JavaScriptCore 0x00000001ec84e130 std::__1::cv_status std::__1::condition_variable_any::wait_until<std::__1::unique_lockbmalloc::Mutex, std::__1::chrono::steady_clock, std::__1::chrono::duration<long long, std::__1::ratio<1l, 1000000000l> > >+ 1564976 (std::__1::unique_lockbmalloc::Mutex&, std::__1::chrono::time_point<std::__1::chrono::steady_clock, std::__1::chrono::duration<long long, std::__1::ratio<1l, 1000000000l> > > const&) + 112
5 JavaScriptCore 0x00000001ec84cda0 bmalloc::Scavenger::threadRunLoop+ 1559968 () + 296
6 JavaScriptCore 0x00000001ec84c458 bmalloc::Scavenger::threadEntryPoint+ 1557592 (bmalloc::Scavenger*) + 12
7 JavaScriptCore 0x00000001ec84df0c void* std::__1::__thread_proxy<std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_deletestd::__1::__thread_struct >, void ()(bmalloc::Scavenger), bmalloc::Scavenger*> >+ 1564428 (void*) + 44
8 libsystem_pthread.dylib 0x00000001e47d65a4 _pthread_body + 132
9 libsystem_pthread.dylib 0x00000001e47d64f8 _pthread_start + 48
10 libsystem_pthread.dylib 0x00000001e47d5374 thread_start + 4

Thread 8 name: WebThread
Thread 8:
0 libsystem_kernel.dylib 0x00000001e4736328 mach_msg_trap + 8
1 libsystem_kernel.dylib 0x00000001e47361a0 mach_msg + 72
2 CoreFoundation 0x00000001e4b61538 __CFRunLoopServiceMachPort + 236
3 CoreFoundation 0x00000001e4b5f1a8 __CFRunLoopRun + 1408
4 CoreFoundation 0x00000001e4a98430 CFRunLoopRunSpecific + 436
5 WebCore 0x00000001edd61f4c RunWebThread+ 274252 (void*) + 592
6 libsystem_pthread.dylib 0x00000001e47d65a4 _pthread_body + 132
7 libsystem_pthread.dylib 0x00000001e47d64f8 _pthread_start + 48
8 libsystem_pthread.dylib 0x00000001e47d5374 thread_start + 4

Thread 9 name: WTF::AutomaticThread
Thread 9:
0 libsystem_kernel.dylib 0x00000001e4758484 __psynch_cvwait + 8
1 libsystem_pthread.dylib 0x00000001e47d909c _pthread_cond_wait$VARIANT$mp + 636
2 JavaScriptCore 0x00000001ec83a88c WTF::ThreadCondition::timedWait+ 1484940 (WTF::Mutex&, WTF::WallTime) + 148
3 JavaScriptCore 0x00000001ec82698c WTF::ParkingLot::parkConditionallyImpl(void const*, WTF::ScopedLambda<bool ()> const&, WTF::ScopedLambda<void + 1403276 ()> const&, WTF::TimeWithDynamicClockType const&) + 2004
4 JavaScriptCore 0x00000001ec80b520 bool WTF::Condition::waitUntilWTF::Lock+ 1291552 (WTF::Lock&, WTF::TimeWithDynamicClockType const&) + 184
5 JavaScriptCore 0x00000001ec80b8c0 WTF::Function<void ()>::CallableWrapper<WTF::AutomaticThread::start(WTF::AbstractLocker const&)::$_0>::call+ 1292480 () + 216
6 JavaScriptCore 0x00000001ec838b3c WTF::Thread::entryPoint+ 1477436 (WTF::Thread::NewThreadContext*) + 256
7 JavaScriptCore 0x00000001ec6d9630 WTF::wtfThreadEntryPoint+ 38448 (void*) + 12
8 libsystem_pthread.dylib 0x00000001e47d65a4 _pthread_body + 132
9 libsystem_pthread.dylib 0x00000001e47d64f8 _pthread_start + 48
10 libsystem_pthread.dylib 0x00000001e47d5374 thread_start + 4

Thread 0 crashed with ARM Thread State (64-bit):
x0: 0x0000000000000000 x1: 0x0000000000000000 x2: 0x0000000000000000 x3: 0x0000000283d80137
x4: 0x00000001e3e54b41 x5: 0x000000016b503fa0 x6: 0x000000000000006e x7: 0xffffffffffffffec
x8: 0x0000000000000800 x9: 0x00000001e47dbe2c x10: 0x00000001e47d73a0 x11: 0x0000000000000003
x12: 0x0000000000000001 x13: 0x0000000000000000 x14: 0x0000000000000010 x15: 0x00000000000007fb
x16: 0x0000000000000148 x17: 0x0000000000000000 x18: 0x0000000000000000 x19: 0x0000000000000006
x20: 0x000000021cd310c0 x21: 0x000000016b503fa0 x22: 0x0000000000000303 x23: 0x000000021cd311a0
x24: 0x000000021cd311a0 x25: 0x0000000000000000 x26: 0x0000000044000000 x27: 0x00000002806c5240
x28: 0x0000000002ffffff fp: 0x000000016b503f00 lr: 0x00000001e47d7520
sp: 0x000000016b503ed0 pc: 0x00000001e475867c cpsr: 0x00000000

anybody could give me a clue of what could go wrong?

[francisco-sanchez-molina]

I think it's the same issue that #19806

[eshikerya]

confirmed. it is crashing with message:
Unhandled JS Exception: Can't find variable: regeneratorRuntime

[elicwhite]

Can you see if moving these two lines:

const ReactNativeVersionCheck = require('ReactNativeVersionCheck');
ReactNativeVersionCheck.checkVersions();

in InitializeCore

to be below the timerSetup fixes this crash?

[eshikerya]

@TheSavior moved down under line defineLazyTimer('cancelIdleCallback');still got same issue:
Unhandled JS Exception: Can't find variable: regeneratorRuntime

[elicwhite]

Try moving the polyfill block: polyfillGlobal('regeneratorRuntime', () => { above the polyfillGlobal('Promise', () => require('Promise')); line.

The reason I'm thinking we should be mucking around here is because I ran into this myself a while back and the issue was that something was crashing but the exception handler required regeneratorRuntime but it hadn't been polyfilled yet.

Do you have a stack trace from the exception?

Can you repro with a debugger statement and step around?

[eshikerya]

@TheSavior it doesn't help. here is what the file is looks like now:

// Set up regenerator.
polyfillGlobal('regeneratorRuntime', () => {
  // The require just sets up the global, so make sure when we first
  // invoke it the global does not exist
  delete global.regeneratorRuntime;
  /* $FlowFixMe(>=0.54.0 site=react_native_oss) This comment suppresses an
   * error found when Flow v0.54 was deployed. To see the error delete this
   * comment and run Flow. */
  require('regenerator-runtime/runtime');
  return global.regeneratorRuntime;
});

// Set up Promise
// The native Promise implementation throws the following error:
// ERROR: Event loop not supported.
polyfillGlobal('Promise', () => require('Promise'));

// Set up timers
const defineLazyTimer = name => {
  polyfillGlobal(name, () => require('JSTimers')[name]);
};
defineLazyTimer('setTimeout');
defineLazyTimer('setInterval');
defineLazyTimer('setImmediate');
defineLazyTimer('clearTimeout');
defineLazyTimer('clearInterval');
defineLazyTimer('clearImmediate');
defineLazyTimer('requestAnimationFrame');
defineLazyTimer('cancelAnimationFrame');
defineLazyTimer('requestIdleCallback');
defineLazyTimer('cancelIdleCallback');

// Check for compatibility between the JS and native code
const ReactNativeVersionCheck = require('ReactNativeVersionCheck');
ReactNativeVersionCheck.checkVersions();

exactly same issue: Unhandled JS Exception: Can't find variable: regeneratorRuntime (/Users/xxx/Library/Developer/CoreSimulator/Devices/25D07A35-FD85-44FA-AD03-18D47AF6F3DA/data/Containers/Bundle/Application/xxx/xxx/main.jsbundle:326)

PS: No stack trace, as far I can get this message from device log, there is no trace. even try-catch doesn't help. I can't debug as far it early initiation. could you suggest the way to debug?

[elicwhite]

Can you repro on a new project and provide easy repro steps for someone else to take a look?

[eshikerya]

@TheSavior
the funny thing: empty project (created by react-native init and upgraded to rc.2 - works ok. just verified. Also I tried to make production build for RNTesterproject, which also is fine.

I would try to add some portions of code from my project until it breaks...
will let you know my findings

[macrozone]

@eshikerya same issue here. Any updates on your side?

[eshikerya]

very strange is going on here. stable code under 55.4 looks wierd now. removed any imports and have just simple screen with fake text, then adding line by line until it breaks, then dig deeper. regular fetch is working, promise is working, redux is working. get stuck it level where im showing login/error screen. not crashing but show empty screen, works under debug build, but not under release. going deeper. will share my finding when i find something...

[macrozone]

@eshikerya on my app it even crashes on the device started on debug from xcode. It runs on the simulator however.

[eshikerya]

anything in console? which issue causing it? mine is Unhandled JS Exception: Can't find variable: regeneratorRuntime