Errors coming from `show` methods are not interactive?

[rafaqz]

When something is shown in the REPL and show throws an error, the stack trace is normal, not interactive.

[MichaelHatherly]

Thanks for reporting.

A reproducible error below. I assume this is what you're refering to, yes?

julia> struct T end

julia> Base.show(io::IO, ::T) = error("bad!")

julia> T()
Error showing value of type T:
ERROR: bad!
Stacktrace:
  [1] error(s::String)
    @ Base ./error.jl:33
  [2] show(io::IOContext{Base.TTY}, #unused#::T)
    @ Main ./REPL[2]:1
  [3] show(io::IOContext{Base.TTY}, #unused#::MIME{Symbol("text/plain")}, x::T)
    @ Base.Multimedia ./multimedia.jl:47
  [4] display(d::REPL.REPLDisplay{REPL.LineEditREPL}, mime::MIME{Symbol("text/plain")}, x::T)
    @ OhMyREPL ~/.julia/packages/OhMyREPL/07uNa/src/output_prompt_overwrite.jl:8
  [5] display(d::REPL.REPLDisplay, x::Any)
    @ REPL ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:225
  [6] display(x::Any)
    @ Base.Multimedia ./multimedia.jl:328
  [7] #invokelatest#2
    @ ./essentials.jl:708 [inlined]
  [8] invokelatest
    @ ./essentials.jl:706 [inlined]
  [9] print_response(errio::IO, response::Any, show_value::Bool, have_color::Bool, specialdisplay::Union{Nothing, AbstractDisplay})
    @ REPL ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:247
 [10] (::REPL.var"#40#41"{REPL.LineEditREPL, Pair{Any, Bool}, Bool, Bool})(io::Any)
    @ REPL ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:231
 [11] with_repl_linfo(f::Any, repl::REPL.LineEditREPL)
    @ REPL ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:462
 [12] print_response(repl::REPL.AbstractREPL, response::Any, show_value::Bool, have_color::Bool)
    @ REPL ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:229
 [13] (::REPL.var"#do_respond#61"{Bool, Bool, REPL.var"#72#82"{REPL.LineEditREPL, REPL.REPLHistoryProvider}, REPL.LineEditREPL, REPL.LineEdit.Prompt})(s::REPL.LineEdit.MIState, buf::Any, ok::Bool)
    @ REPL ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:798
 [14] #invokelatest#2
    @ ./essentials.jl:708 [inlined]
 [15] invokelatest
    @ ./essentials.jl:706 [inlined]
 [16] run_interface(terminal::REPL.Terminals.TextTerminal, m::REPL.LineEdit.ModalInterface, s::REPL.LineEdit.MIState)
    @ REPL.LineEdit ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/LineEdit.jl:2441
 [17] run_frontend(repl::REPL.LineEditREPL, backend::REPL.REPLBackendRef)
    @ REPL ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:1126
 [18] (::REPL.var"#44#49"{REPL.LineEditREPL, REPL.REPLBackendRef})()
    @ REPL ./task.jl:411

julia> toggle()
false

julia> T()
Error showing value of type T:
ERROR: bad!
Stacktrace:
  [1] error(s::String)
    @ Base ./error.jl:33
  [2] show(io::IOContext{Base.TTY}, #unused#::T)
    @ Main ./REPL[2]:1
  [3] show(io::IOContext{Base.TTY}, #unused#::MIME{Symbol("text/plain")}, x::T)
    @ Base.Multimedia ./multimedia.jl:47
  [4] display(d::REPL.REPLDisplay{REPL.LineEditREPL}, mime::MIME{Symbol("text/plain")}, x::T)
    @ OhMyREPL ~/.julia/packages/OhMyREPL/07uNa/src/output_prompt_overwrite.jl:8
  [5] display(d::REPL.REPLDisplay, x::Any)
    @ REPL ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:225
  [6] display(x::Any)
    @ Base.Multimedia ./multimedia.jl:328
  [7] #invokelatest#2
    @ ./essentials.jl:708 [inlined]
  [8] invokelatest
    @ ./essentials.jl:706 [inlined]
  [9] print_response(errio::IO, response::Any, show_value::Bool, have_color::Bool, specialdisplay::Union{Nothing, AbstractDisplay})
    @ REPL ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:247
 [10] (::REPL.var"#40#41"{REPL.LineEditREPL, Pair{Any, Bool}, Bool, Bool})(io::Any)
    @ REPL ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:231
 [11] with_repl_linfo(f::Any, repl::REPL.LineEditREPL)
    @ REPL ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:462
 [12] print_response(repl::REPL.AbstractREPL, response::Any, show_value::Bool, have_color::Bool)
    @ REPL ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:229
 [13] (::REPL.var"#do_respond#61"{Bool, Bool, REPL.var"#72#82"{REPL.LineEditREPL, REPL.REPLHistoryProvider}, REPL.LineEditREPL, REPL.LineEdit.Prompt})(s::REPL.LineEdit.MIState, buf::Any, ok::Bool)
    @ REPL ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:798
 [14] #invokelatest#2
    @ ./essentials.jl:708 [inlined]
 [15] invokelatest
    @ ./essentials.jl:706 [inlined]
 [16] run_interface(terminal::REPL.Terminals.TextTerminal, m::REPL.LineEdit.ModalInterface, s::REPL.LineEdit.MIState)
    @ REPL.LineEdit ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/LineEdit.jl:2441
 [17] run_frontend(repl::REPL.LineEditREPL, backend::REPL.REPLBackendRef)
    @ REPL ~/usr/julia/1.6/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:1126
 [18] (::REPL.var"#44#49"{REPL.LineEditREPL, REPL.REPLBackendRef})()
    @ REPL ./task.jl:411

Disabling interactive errors with toggle() doesn't appear to change the stack at all so it would appear that this isn't handled by the same code path as the rest of the error printing... You can also see that the stacktrace isn't cleaned up at all like it should, there's REPL internals printed. This may be something that's actually an upstream issue perhaps.

[rafaqz]

Yep, exactly. Somehow my attrempt at a MWE was throwing an unrelated problem with display.

[MichaelHatherly]

Even if this could be regarded as just an upstream issue, I'd like to fix it here anyway.