Crash trying to compile a flutter app with macros

[jakemac53]

I am trying to test out macros in flutter but am getting a failure today for flutter run -d linux.

You can try my example by cloning https://github.com/jakemac53/macros_example/tree/flutter-app, and running flutter run --enable-experiment macros -d linux (or whichever device you have locally set up, it probably isn't linux specific as this is a kernel compilation failure).

I get the error below:

flutter run --enable-experiment macros -d linux
Launching lib/main.dart on Linux in debug mode...
Unhandled exception:
Crash when compiling:
Unsupported operation: Unexpected library member DynamicTypeDeclarationBuilder(dynamic) (DynamicTypeDeclarationBuilder)

#0      MacroApplications._computeSourceLibraryMacroApplicationData (package:front_end/src/fasta/kernel/macro/macro.dart:518)
#1      MacroApplications.computeLibrariesMacroApplicationData (package:front_end/src/fasta/kernel/macro/macro.dart:374)
#2      SourceLoader.computeMacroApplications (package:front_end/src/fasta/source/source_loader.dart:1719)
#3      KernelTarget.buildOutlines.<anonymous closure> (package:front_end/src/fasta/kernel/kernel_target.dart:436)
#4      withCrashReporting (package:front_end/src/fasta/crash.dart:133)
#5      KernelTarget.buildOutlines (package:front_end/src/fasta/kernel/kernel_target.dart:415)
#6      _buildInternal (package:front_end/src/kernel_generator_impl.dart:151)
#7      generateKernelInternal.<anonymous closure> (package:front_end/src/kernel_generator_impl.dart:119)
<asynchronous suspension>
#8      withCrashReporting (package:front_end/src/fasta/crash.dart:133)
<asynchronous suspension>
#9      kernelForProgramInternal.<anonymous closure> (package:front_end/src/api_prototype/kernel_generator.dart:65)
<asynchronous suspension>
#10     CompilerContext.clear (package:front_end/src/fasta/compiler_context.dart:139)
<asynchronous suspension>
#11     kernelForProgramInternal (package:front_end/src/api_prototype/kernel_generator.dart:64)
<asynchronous suspension>
#12     _compileMacros (package:front_end/src/kernel_generator_impl.dart:365)
<asynchronous suspension>
#13     precompileMacros (package:front_end/src/kernel_generator_impl.dart:314)
<asynchronous suspension>
#14     IncrementalCompiler.computeDelta.<anonymous closure> (package:front_end/src/fasta/incremental_compiler.dart:347)
<asynchronous suspension>
#15     CompilerContext.clear (package:front_end/src/fasta/compiler_context.dart:139)
<asynchronous suspension>
#16     IncrementalCompiler.compile (package:vm/incremental_compiler.dart:77)
<asynchronous suspension>
#17     FrontendCompiler.compile (package:frontend_server/frontend_server.dart:617)
<asynchronous suspension>
#18     listenAndCompile.<anonymous closure> (package:frontend_server/frontend_server.dart:1311)
<asynchronous suspension>
the Dart compiler exited unexpectedly.

[davidmorgan]

Started digging into this; it looks like a config issue, so, hopefully I can fix it :)

[davidmorgan]

Okay there's a bunch to unpack here, that I will dig into tomorrow :)

• Flutter platform dill is called product_strong.dill, not vm_product_strong.dill, so macro_target.dart picks the wrong file, that's an easy fix :)
• VmTarget doesn't work to compile the macro, FlutterTarget does ... needs some digging.
• frontend_server.dart calls writeDepfile in package:vm/kernel_front_end.dart, which chokes on the macro URI; we can probably just skip it, needs checking.

And this is enough to get a macro in the "hello world" app working for target "linux". (i.e. desktop).

[DanTup]

@davidmorgan do you have a branch or something where this is working? I'm interested in doing some testing with the Flutter debug adapter to see if everything "just works".. it's not important to me if everything works or is merged, but if I can rig it enough to run locally, it could give me a head-start on testing :-)

[davidmorgan]

Sure, just about :) ... happy to have more people trying it :)

"flutter run" with "-d linux" or "-d chrome" are working after

https://dart-review.googlesource.com/c/sdk/+/358443 -- which just merged
https://dart-review.googlesource.com/c/sdk/+/358700 -- running through CQ

--you'll need flutter set up to run with a locally built Dart SDK, until the change rolls into flutter properly.

Looking next at getting it running with emulators.

[DanTup]

@davidmorgan thanks! Is the Linux support specific to Linux, or would those fixes also apply to macOS or Windows desktop? (I don't currently have easy access to Linux).

Being able to use Web is very useful though, I haven't yet been able to test debugging web+macros at all! :)