Julia and Revise.jl make Kernel unresponsive

[bachdavi]

Hey there! Great work and its been a pleasure using it :)

When running a Julia kernel together with the Revise.jl package the kernel gets unresponsive upon the first hook from revise.

Revise detects changes in functions from a module and injects them into the running Julia session.

To use Revise.jl I added two startup files with the following content:

~/.julia/config/startup.jl

atreplinit() do repl
    try
        @eval using Pkg
        haskey(Pkg.installed(), "Revise") || @eval Pkg.add("Revise")
    catch
    end
    try
        @eval using Revise
        @async Revise.wait_steal_repl_backend()
    catch
    end
end

and

~/.julia/config/startup_ijulia.jl

try
    @eval using Revise
catch
end

With this setup, running julia or jupyter console --kernel julia-1.3 results in correctly reloading Julia sessions.

To test the setup, I generated a new package from the Julia package REPL.

using Pkg

Pkg.generate("TestPackage")

This generates a directory TestPackage which contains a simple TestPackage.jl file.

We start a session in the directory and evaluate the following snippet:

using Pkg

Pkg.activate(".")

using TestPackage

TestPackage.greet()

We can then go and add a function to the TestPackage.jl file.

function f()
    π
end

And Revise.jl will inject that code into the running session, and we can use it.

TestPackage.f()

Using the kernel from emacs-jupyter results in a busy kernel as soon as we save the source file.

Any ideas why that might happen?

emacs-jupyter 20191019.1519

julia version 1.3.0

jupyter core     : 4.6.1
jupyter-notebook : 6.0.1
qtconsole        : 4.3.1
ipython          : 7.9.0
ipykernel        : 5.1.3
jupyter client   : 5.3.4
jupyter lab      : not installed
nbconvert        : 5.6.1
ipywidgets       : 7.4.0
nbformat         : 4.4.0
traitlets        : 4.3.3

Cheers

[bachdavi]

A current workaround is starting a kernel outside of emacs and connecting to it via: jupyter-connect-repl

[benneti]

I think the problem is somehow related to loading Revise.jl in your startup_ijulia.jl file. I can using Revise without a problem in a source block (and then use the functionality of it in the following executed blocks).

[nnicandro]

Great work and its been a pleasure using it :)

Thanks, and sorry for the late reply.

Any ideas why that might happen?

I'm not sure, but I will use your test case to see if I can find out why. In the meantime, you may be able to find out something if you evaluate (setq jupyter--debug t) and try again. You should see the flow of messages between Emacs and the kernel in the *Messages* buffer.