On Windows, Julia warnings don't show

[edwardlavender]

On Windows, Julia warnings from @warn don't show. This issue has been replicated with Julia v1.9.4 and 1.10.5 on Windows 10. Here is a reprex:

library(JuliaCall)
julia_command('@warn "This is a warning"')

On MacOS, this returns

┌ Warning: This is a warning
└ @ Main none:1

But on Windows nothing is returned.

[edwardlavender]

The issue remains if you use a custom warning struct:

julia_code(
    '
    struct JuliaWarning
      msg::String
    end
    
    function warning_convergence(w::JuliaWarning)
      println("Warning: ", w.msg)
    end
   '
)

We run the warning with

julia_command('warning_convergence(JuliaWarning("The particle filter failed to converge."))')

On MacOS, this returns

Warning: The particle filter failed to converge.

But on Windows nothing is returned.

[edwardlavender]

See also JuliaInterop/JuliaCall#76