Juno.@enter exits with error when running PyPlot.plot()

[zhopan77]

I have a very simple script as shown below:

ENV["MPLBACKEND"] = "qt4agg";
using PyPlot

function main()
x = LinRange(0, 3, 10);
y = sin.(x);
plot(x, y);
end

main();

This script runs fine in Juno IDE. Note I have to set up environmental variable MPLBACKEND to "qt4agg" for my Anaconda Python 2.7 matplotlib to work with Julia properly.

However, if I start debugging it by executing
Juno.@Enter main()

I can step until I reach "plot(x, y)", upon executing which the plot shows up (I'm not using Juno plot plane so it's a standalone window), then the debugger exits with the following error message:

julia> Juno.@Enter main()
debug> ERROR: sigatomic_end called in non-sigatomic region
Stacktrace:
[1] #evaluate_call_recurse!#37(::Bool, ::Function, ::Any, ::JuliaInterpreter.Frame, ::Expr) at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\interpret.jl:209
[2] evaluate_call_recurse! at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\interpret.jl:198 [inlined]
[3] eval_rhs(::Any, ::JuliaInterpreter.Frame, ::Expr) at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\interpret.jl:364
[4] step_expr!(::Any, ::JuliaInterpreter.Frame, ::Any, ::Bool) at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\interpret.jl:497
[5] step_expr!(::Any, ::JuliaInterpreter.Frame, ::Bool) at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\interpret.jl:536
[6] finish!(::Any, ::JuliaInterpreter.Frame, ::Bool) at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\commands.jl:14
[7] finish_and_return! at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\commands.jl:29 [inlined]
[8] #evaluate_call_recurse!#37(::Bool, ::Function, ::Any, ::JuliaInterpreter.Frame, ::Expr) at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\interpret.jl:235
... (the last 7 lines are repeated 5 more times)
[44] evaluate_call_recurse! at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\interpret.jl:198 [inlined]
[45] eval_rhs(::Any, ::JuliaInterpreter.Frame, ::Expr) at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\interpret.jl:364
[46] step_expr!(::Any, ::JuliaInterpreter.Frame, ::Any, ::Bool) at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\interpret.jl:492
[47] step_expr!(::Any, ::JuliaInterpreter.Frame, ::Bool) at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\interpret.jl:536
[48] next_line!(::Any, ::JuliaInterpreter.Frame, ::Bool) at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\commands.jl:217
[49] debug_command(::Any, ::JuliaInterpreter.Frame, ::Symbol, ::Bool) at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\commands.jl:424
[50] debug_command at C:\Users\zpan.julia\packages\JuliaInterpreter\8bMSs\src\commands.jl:477 [inlined]
[51] (::getfield(Atom.JunoDebugger, Symbol("##45#47")){Bool})() at C:\Users\zpan.julia\packages\Atom\mngyX\src\debugger\stepper.jl:81
[52] evalscope(::getfield(Atom.JunoDebugger, Symbol("##45#47")){Bool}) at C:\Users\zpan.julia\packages\Atom\mngyX\src\debugger\stepper.jl:315
[53] startdebugging(::JuliaInterpreter.Frame, ::Bool) at C:\Users\zpan.julia\packages\Atom\mngyX\src\debugger\stepper.jl:55

[baggepinnen]

I'm seeing the same thing with a call to OpenAIGym

[timholy]

Best workaround would be to temporarily uncomment these lines so you know what's being attempted. Then push! the sigatomic method to JuliaInterpreter.compiled_methods. Some examples are here. You can see a reference to sigatomic Base methods there, but obviously packages that use it can't so easily be guarded.

[tkf]

It looks like push!(JuliaInterpreter.compiled_modules, PyCall) works: https://discourse.julialang.org/t/debugger-fails-on-pycall/23560/6

[KristofferC]

"Fixed" upstream in JuliaPy/PyCall.jl#684.