CTRL+C is even worse on 1.13

[denglerchr]

This is working on Julia 1.11, therefore I assume there is an issue in Julia (tested on Windows). Im using Juliaup to install Julia. The bug report includes usage of Oxygen (1.7.1), I posting here though as the bug only happens on Julia 1.12 .

First about my machine

julia> versioninfo()
Julia Version 1.12.0-beta4
Commit 600ac61d3d (2025-06-05 07:03 UTC)
Build Info:
  Official https://julialang.org release
Platform Info:
  OS: Windows (x86_64-w64-mingw32)
  CPU: 16 × 11th Gen Intel(R) Core(TM) i9-11900H @ 2.50GHz
  WORD_SIZE: 64
  LLVM: libLLVM-18.1.7 (ORCJIT, tigerlake)
  GC: Built with stock GC
Threads: 1 default, 1 interactive, 1 GC (on 16 virtual cores)

Minimal example:

julia> using Oxygen
julia> serve()

Then hit CTRL+C .

On Julia 1.12 this crashed the REPL with this error message.

julia> Unhandled Task ERROR: TaskFailedException
Stacktrace:
 [1] #wait#583
   @ .\task.jl:363 [inlined]
 [2] wait
   @ .\task.jl:360 [inlined]
 [3] fetch
   @ .\task.jl:525 [inlined]
 [4] prompt!(term::REPL.Terminals.TextTerminal, prompt::REPL.LineEdit.ModalInterface, s::REPL.LineEdit.MIState)
   @ REPL.LineEdit C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\LineEdit.jl:2983
 [5] run_interface(terminal::REPL.Terminals.TextTerminal, m::REPL.LineEdit.ModalInterface, s::REPL.LineEdit.MIState)
   @ REPL.LineEdit C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\LineEdit.jl:2849
 [6] run_frontend(repl::REPL.LineEditREPL, backend::REPL.REPLBackendRef)
   @ REPL C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\REPL.jl:1664
 [7] (::REPL.var"#61#62"{REPL.LineEditREPL, REPL.REPLBackendRef})()
   @ REPL C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\REPL.jl:651

    nested task error: InterruptException:
    Stacktrace:
     [1] yieldto(t::Task, x::Any)
       @ Base .\task.jl:1101
     [2] yieldto
       @ .\task.jl:1095 [inlined]
     [3] wait()
       @ Base .\task.jl:1213
     [4] wait(c::Base.GenericCondition{Base.Threads.SpinLock}; first::Bool)
       @ Base .\condition.jl:141
     [5] wait
       @ .\condition.jl:136 [inlined]
     [6] wait_readnb(x::Base.TTY, nb::Int64)
       @ Base .\stream.jl:416
     [7] eof(s::Base.TTY)
       @ Base .\stream.jl:106
     [8] eof(io::REPL.Terminals.TTYTerminal)
       @ Base .\io.jl:472
     [9] (::REPL.LineEdit.var"#prompt!##2#prompt!##3"{REPL.Terminals.TTYTerminal, REPL.LineEdit.ModalInterface, REPL.LineEdit.MIState, REPL.LineEdit.Prompt})()
       @ REPL.LineEdit C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\LineEdit.jl:2948
ERROR: TaskFailedException
Stacktrace:
  [1] try_yieldto(undo::typeof(Base.ensure_rescheduled))
    @ Base .\task.jl:1128
  [2] wait()
    @ Base .\task.jl:1225
  [3] wait(c::Base.GenericCondition{ReentrantLock}; first::Bool)
    @ Base .\condition.jl:141
  [4] wait
    @ .\condition.jl:136 [inlined]
  [5] take_buffered(c::Channel{Any})
    @ Base .\channels.jl:532
  [6] take!
    @ .\channels.jl:526 [inlined]
  [7] repl_backend_loop(backend::REPL.REPLBackend, get_module::Function)
    @ REPL C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\REPL.jl:438
  [8] start_repl_backend(backend::REPL.REPLBackend, consumer::Any; get_module::Function)
    @ REPL C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\REPL.jl:428
  [9] start_repl_backend
    @ C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\REPL.jl:425 [inlined]
 [10] run_repl(repl::REPL.AbstractREPL, consumer::Any; backend_on_current_task::Bool, backend::Any)
    @ REPL C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\REPL.jl:654
 [11] run_repl(repl::REPL.AbstractREPL, consumer::Any)
    @ REPL C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\REPL.jl:640
 [12] run_std_repl(REPL::Module, quiet::Bool, banner::Symbol, history_file::Bool)
    @ Base .\client.jl:482
 [13] run_main_repl(interactive::Bool, quiet::Bool, banner::Symbol, history_file::Bool)
    @ Base .\client.jl:503
 [14] repl_main
    @ .\client.jl:590 [inlined]
 [15] _start()
    @ Base .\client.jl:565

    nested task error: TaskFailedException
    Stacktrace:
     [1] #wait#583
       @ .\task.jl:363 [inlined]
     [2] wait
       @ .\task.jl:360 [inlined]
     [3] fetch
       @ .\task.jl:525 [inlined]
     [4] prompt!(term::REPL.Terminals.TextTerminal, prompt::REPL.LineEdit.ModalInterface, s::REPL.LineEdit.MIState)
       @ REPL.LineEdit C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\LineEdit.jl:2983
     [5] run_interface(terminal::REPL.Terminals.TextTerminal, m::REPL.LineEdit.ModalInterface, s::REPL.LineEdit.MIState)
       @ REPL.LineEdit C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\LineEdit.jl:2849
     [6] run_frontend(repl::REPL.LineEditREPL, backend::REPL.REPLBackendRef)
       @ REPL C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\REPL.jl:1664
     [7] (::REPL.var"#61#62"{REPL.LineEditREPL, REPL.REPLBackendRef})()
       @ REPL C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\REPL.jl:651

        nested task error: InterruptException:
        Stacktrace:
         [1] yieldto(t::Task, x::Any)
           @ Base .\task.jl:1101
         [2] yieldto
           @ .\task.jl:1095 [inlined]
         [3] wait()
           @ Base .\task.jl:1213
         [4] wait(c::Base.GenericCondition{Base.Threads.SpinLock}; first::Bool)
           @ Base .\condition.jl:141
         [5] wait
           @ .\condition.jl:136 [inlined]
         [6] wait_readnb(x::Base.TTY, nb::Int64)
           @ Base .\stream.jl:416
         [7] eof(s::Base.TTY)
           @ Base .\stream.jl:106
         [8] eof(io::REPL.Terminals.TTYTerminal)
           @ Base .\io.jl:472
         [9] (::REPL.LineEdit.var"#prompt!##2#prompt!##3"{REPL.Terminals.TTYTerminal, REPL.LineEdit.ModalInterface, REPL.LineEdit.MIState, REPL.LineEdit.Prompt})()
           @ REPL.LineEdit C:\Users\dengl\.julia\juliaup\julia-1.12.0-beta4+0.x64.w64.mingw32\share\julia\stdlib\v1.12\REPL\src\LineEdit.jl:2948

[gbaraldi]

That's unfortunately not weird. You sent an asynchronous exception to your program, which can and did cause the scheduler to get in a bad state. So not much that can be done. Not sure if we want to close this but there's around 15 other issues that observe this so I'll take this off the milestone. If someone wants to bisect this then maybe we can change this slightly

[denglerchr]

This was not an issue in previous Julia versions, why do you believe there is not much that can be done? I assume this is a bug and it needs fixing?

[gbaraldi]

This is a bug and should be fixed. But it's not release blocking. It's one of several issues with ctrl-c handling (just search for ctrl-c in the issue tracker). The fact that this used to work and doesn't doesn't mean that there wasn't an underlying bug before that's still there and is now exposed differently

[Keno]

This is caused by #57544 (comment) which is new in 1.12. This change basically makes 1.12 guaranteed to get corrupted by ^C, whereas before there was at least a chance this worked. I think this is bad enough that it needs to be on the milestone.

[vtjnash]

Do we not properly try/catch/restart that task?

[Keno]

We don't, but even if we did that, that would just result in us swallowing all InterruptExceptions.

[JamesWrigley]

IJulia is also affected by this, on 1.12 notebook() and jupyterlab() will completely crash Julia when hitting Ctrl + C to stop the notebook server. Relevant code is here: https://github.com/JuliaLang/IJulia.jl/blob/b4d91ee86972601c2082f0d5a14830000cf8c5f1/src/jupyter.jl#L61

[kpamnany]

@denglerchr and/or @JamesWrigley: could I ask you to try out this fix and let us know if it returns the old behavior?

[JamesWrigley]

Yep, I ran notebook() a few times and it seems to work:

julia> versioninfo()
Julia Version 1.13.0-DEV.751
Commit b4e747c5396* (2025-06-17 18:54 UTC)
Platform Info:
  OS: Linux (x86_64-redhat-linux)
  CPU: 12 × Intel(R) Core(TM) i7-10850H CPU @ 2.70GHz
  WORD_SIZE: 64
  LLVM: libLLVM-20.1.2 (ORCJIT, skylake)
  GC: Built with stock GC
Threads: 1 default, 1 interactive, 1 GC (on 12 virtual cores)
Environment:
  LD_LIBRARY_PATH = :/opt/zfp/lib64:/opt/adios2/lib:/usr/lib64/openmpi/lib:/usr/local/lib
  JULIA_EDITOR = vim