When using vterm as backend, `C-c C-z` opens a split but fails to start vterm

[johnhamelink]

with my .dir-config.el like so:

(set-language-environment "UTF-8")
(setq julia-snail-executable (executable-find "julia"))
(julia-repl-set-terminal-backend 'vterm) 

If I try to run C-c C-z, Emacs opens a new split window containing the file buffer of the .jl file. However if I open a vterm window, rename the buffer to *julia*, then try the same commands, they work as expected. 'eat and 'ansi-term work as expected right out of the box.

I'm using Emacs 31.0.50 and julia-repl 20250719.1449. Is anyone else experiencing this issue?

[tpapp]

I am confused, are you using julia-snail or julia-repl?

What is C-c C-z bound to? (try C-h k)

[wentasah]

I'm also confused. C-c C-z should work the opposite way. When you're visiting a .jl file, C-c C-z (julia-repl) starts or switches to Julia in *julia* buffer and remembers where you came from. Then, when you press C-c C-z in the *julia* buffer, it switches back to the remembered .jl file.

When you start pressing C-c C-z in *julia* buffer, it either does nothing or switches to some other buffer that was active before you started julia. What is your expected behavior you see with eat and ansi-vterm?

[johnhamelink]

Apologies, I can see how that would be confusing! I removed julia-snail after trying it - that was a red herring. C-c -z resolves to (julia-repl).

I made a short screen recording to demonstrate what I'm doing - you can see the keys pressed in the tabbar on the top-right. I hope that helps clarify! (NB: I know that the :custom is wrong since julia-repl-set-terminal-backend is a callable - I've since removed that).

screenrecord.mp4

[wentasah]

Do you have vterm modules installed (does M-x vterm open a shell)? Do you see any errors in *Messages*?

[johnhamelink]

@wentasah Yes, I have vterm. No errors in *Messages*. I think that for some reason julia-repl isn't able to initialise vterm - perhaps it bails after creating the split for vterm to exist in.

[johnhamelink]

Here's a video of me getting it to kinda-work by renaming the vterm buffer after creating it manually.

screenrecord.mp4

[wentasah]

I have no idea what's going on. I think you'll have to use edebug to step through julia-repl--make-buffer and related methods and figure out where's the problem. Let me know if you need some help.