Hot reload fails on incremental kernel file due to redirecting factory

[aam]

#redirecting_factory declaration below seems to be invalid(invalid-expression)

  abstract class GlobalKey<T extends fra2::State<fra2::StatefulWidget>> extends fra2::Key {
...
    static factory •<T extends fra2::State<fra2::StatefulWidget>>({core::String debugLabel}) → fra2::GlobalKey<fra2::GlobalKey::•::T>
      let dynamic #redirecting_factory = fra2::LabeledGlobalKey::_ in invalid-expression;

generated from https://github.com/flutter/flutter/blob/master/packages/flutter/lib/src/widgets/framework.dart#L178

abstract class GlobalKey<T extends State<StatefulWidget>> extends Key {
  factory GlobalKey({ String debugLabel }) = LabeledGlobalKey<T>._;
  const GlobalKey.constructor() : super._();

fails during hot reload in StreamingFlowGraphBuilder#BuildVariableDeclaration on #redirecting_factory.

[   +3 ms] I/DartVM  ( 3956): BuildGraphOfFunction dart_function: Function 'RecipeGridPage.': constructor const.
[        ] I/DartVM  ( 3956): BuildGraphOfFunction dart_function: Function 'createState':.
[        ] I/DartVM  ( 3956): BuildGraphOfFunction dart_function: Function '_RecipeGridPageState@349046805.': constructor.
[        ] I/DartVM  ( 3956): BuildGraphOfFunction dart_function: Function 'GlobalKey.': static factory.
[        ] I/DartVM  ( 3956): BuildVariableDeclaration name=#redirecting_factory
[        ] I/DartVM  ( 3956): BuildStaticGet unimplemented with target=_@39042623, function=Function: null
[        ] E/DartVM  ( 3956): ../../dart/runtime/vm/compiler/frontend/kernel_binary_flowgraph.cc: 5501: error: unimplemented code
[        ] E/DartVM  ( 3956): Dumping native stack trace for thread fac
[        ] E/DartVM  ( 3956):   [0xd74730dd] Unknown symbol
[        ] E/DartVM  ( 3956):   [0xd74730dd] Unknown symbol
[        ] E/DartVM  ( 3956):   [0xd770a529] Unknown symbol
[        ] E/DartVM  ( 3956):   [0xd758dc7f] Unknown symbol
[        ] E/DartVM  ( 3956):   [0xd7589c3d] Unknown symbol
[        ] E/DartVM  ( 3956):   [0xd7593e87] Unknown symbol
[   +1 ms] E/DartVM  ( 3956):   [0xd7589ef3] Unknown symbol
[        ] E/DartVM  ( 3956):   [0xd758cae5] Unknown symbol
[        ] E/DartVM  ( 3956):   [0xd758c3f5] Unknown symbol
[        ] E/DartVM  ( 3956):   [0xd758cded] Unknown symbol
[        ] E/DartVM  ( 3956):   [0xd759f7d5] Unknown symbol
[        ] E/DartVM  ( 3956):   [0xd75bb625] Unknown symbol
[        ] E/DartVM  ( 3956):   [0xd75bdefd] Unknown symbol
[   +1 ms] E/DartVM  ( 3956):   [0xd75bf63b] Unknown symbol
[        ] E/DartVM  ( 3956):   [0xd75bf101] Unknown symbol
[        ] E/DartVM  ( 3956):   [0xd75bba49] Unknown symbol
[        ] E/DartVM  ( 3956): -- End of DumpStackTrace
[   +5 ms] F/libc    ( 3956): Fatal signal 6 (SIGABRT), code -

There seem to be no errors/warning produced for that Dart code

 $FH/engine/src/out/host_debug_unopt/dart-sdk/bin/dart $FH/engine/src/out/host_debug_unopt/gen/frontend_server.dart.snapshot --sdk-root $FH/engine/src/out/android_debug_unopt/flutter_patched_sdk --incremental $FH/flutter/examples/flutter_gallery/lib/main.dart                                                                                        
result 47b9fb8b-f2b6-4cfc-87f7-339ba117b0fe
Warning: line 1, column 11276 of ../../packages/flutter/lib/src/rendering/binding.dart: Superclass has no method named 'hitTest'.
Nit: line 1, column 229 of lib/demo/material/date_and_time_picker_demo.dart: Import of 'TextDirection' (from 'package:intl/intl.dart') hides import from 'dart:ui'.
Nit: line 1, column 271 of lib/demo/material/full_screen_dialog_demo.dart: Import of 'TextDirection' (from 'package:intl/intl.dart') hides import from 'dart:ui'.
Nit: line 1, column 235 of lib/gallery/item.dart: Import of 'Flow' (from 'package:flutter/src/widgets/basic.dart') hides import from 'dart:developer'.
47b9fb8b-f2b6-4cfc-87f7-339ba117b0fe flutter/flutter/examples/flutter_gallery/lib/main.dart.dill

[aam]

@peter-ahe-google @sigmundch

[aam]

@rmacnak-google

[rmacnak-google]

I wouldn't expect us to build a flow graph for a redirecting factory at all. Perhaps something neglected to follow the redirection.

[aam]

https://github.com/flutter/flutter/blob/master/examples/flutter_gallery/lib/demo/pesto_demo.dart#L75 is the redirecting constructor invocation, which is invoked from RecipeGridPage::createState at https://github.com/flutter/flutter/blob/master/examples/flutter_gallery/lib/demo/pesto_demo.dart#L71.

[aam]

@jensjoha

[aam]

Just remembered that let dynamic #redirecting_factory = fra2::LabeledGlobalKey::_ in invalid-expression; is a valid way to represent redirecting factory constructors in Kernel and the question is why GlobalKey constructor was invoked as it was supposed to be redirected to invocation of LabeledGlobalKey constructor.

[aam]

The issue seems to be with kernel file produced by incremental compilation. Instead of having invocation of target constructor(LabeledGlobalKey) produced in kernel file, it has invocation of redirecting constructor(GlobalKey):

full kernel file:

  class _RecipeGridPageState extends fra::State<pes::RecipeGridPage> {
    final field fra::GlobalKey<sca2::ScaffoldState> scaffoldKey = new fra::LabeledGlobalKey::_<sca2::ScaffoldState>();
    default constructor •() → void
      : super fra::State::•()
      ;
    @core::override

incremental kernel file:

class _RecipeGridPageState extends fra::State<pes::RecipeGridPage> {
    final field fra::GlobalKey<sca::ScaffoldState> scaffoldKey = fra::GlobalKey::•<sca::ScaffoldState>();
    default constructor •() → void
      : super fra::State::•()
      ;

@scheglov

[scheglov]

https://dart-review.googlesource.com/#/c/sdk/+/8381

[a-siva]

Can this be closed?

[aam]

Yes, all good now.