coyote replay --break does not wait for debugger to attach

[thepalbi]

Hi Coyote team!

I'm playing around with the Coyote toolset with the HelloWorldTasks example. I want to try the coyote replay tool. I'm trying the following:

1- Run coyote test ./obj/Release/netcoreapp3.1/osx-x64/HelloWorldTasks.dll --iterations 100 to generate the faulty trace
2- Run coyote replay ./obj/Release/netcoreapp3.1/osx-x64/HelloWorldTasks.dll ./obj/Release/netcoreapp3.1/osx-x64/Output/HelloWorldTasks.dll/CoyoteOutput/HelloWorldTasks_0_1.schedule --break to replay the program with that trace
3- Expect that the coyote runtime will wait for a debugger to attach until it starts reproducing it. Not sure of this, that's my assumption of how it sould work

Any advice on how to use it? (I'm working with MacOS if it help in some way)

[akashlal]

I just tried this on my windows machine and I get a prompt to attach the debugger. Perhaps mac requires a different API to launch (or enable) the debugger? @lovettchris any ideas?

[akashlal]

You can try a workaround. You can go edit the source code of HelloWorldTasks and insert a breakpoint yourself at the beginning of the test (I usually do Debugger.Launch). Then you can rebuild and try coyote replay with the same schedule file. There is no need to rerun coyote test because the same schedule would still work for the test.

[thepalbi]

Thanks for answering @akashlal . Just tried what you suggested and is also not working. I asked in the dotnet issues section to check if it's supported. dotnet/runtime#41029

[akashlal]

Ok, the issue then is to figure out how to attach the debugger from dotnet on mac. If you find out the answer, let us know so we can implement the same in coyote.

[lovettchris]

Looks like from the runtime thread Debugger.Launch is not supported, so what you can do instead is "start" coyote replay in your debugger. I have not use VS on the Mac, but on Windows I can create any random console app and change the "Debug" tab to tell the debugger to launch something else instead, namely, dotnet.dll, with the command line arguments of coyote replay ./obj/Release/netcoreapp3.1/osx-x64/HelloWorldTasks.dll ./obj/Release/netcoreapp3.1/osx-x64/Output/HelloWorldTasks.dll/CoyoteOutput/HelloWorldTasks_0_1.schedule and then you should be able to put a breakpoint in your early code and continue on debugging into the replay that way.

[thepalbi]

Thanks @lovettchris . The approach on launching coyote from VS worked.
In case anyone is interested:
1- Create a new Run Configuration
2- Execute the coyote binary, which is in /Users/thepalbi/.dotnet/tools/coyote in MacOS
3- Add the arguments replay ./obj/Release/netcoreapp3.1/osx-x64/HelloWorldTasks.dll ./obj/Release/netcoreapp3.1/osx-x64/Output/HelloWorldTasks.dll/CoyoteOutput/HelloWorldTasks_0_1.schedule
4- Insert the breakpoints where needed

There's no support for Debugger.Launch in either MacOS or Linux.