Hints on 1.11 slow down REPL text entry

[urbainvaes]

Apologies in advance for the somewhat vague nature of this question. The reason for the issue described below may not be entirely due to Julia, but what is sure is that recent changes in Julia made it apparent.

The issue: with previous versions of Julia, I could programmatically feed chunks of code, from a Neovim buffer containing Julia code to a Julia REPL running inside a Neovim terminal, using either the chansend() function or the put command in vimscript. There are various plugins to automate this, for example my own, but the issue is not limited to a particular plugin.

With the most recent version of Julia (edit ≥ 1.11.0), the reliability of this workflow (either with chansend() or put) has degraded significantly: code sent programmatically to the Julia REPL takes a long time to run (as if the REPL was copy/pasting the lines one by one, with a small time delay between each line), and the indentation is sometimes all jumbled. What is very strange is that, if I manually copy and paste a block of code, then the REPL behaves as it previously did — the REPL runs fast and the indentation is correct.

Here is a minimal working example to reproduce this issue.

• Create file test.vim with the following content:

let script =<<EOF
using TickTock
# Discard compilation time
tick(); tock();
tick()
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
a = "a somewhat long line of code, made a bit longer, and again a bit longer"
tock()

EOF

vsplit | term julia
call chansend(&channel, script)
startinsert

• Open the file in Neovim without any plugins: nvim -u NONE test.vim
• From within Neovim, run :source %. This will open a Julia REPL in a Neovim terminal, and run the script contained in the variable script in that terminal.

Result: In Julia LTS, this takes less than 100ms, but in Julia Release, it sometimes takes more than 2 seconds.

How can I restore the previous behavior of the REPL?

[KristofferC]

With the most recent version of Julia (1.11)

Are you saying that 1.11.4 is better than 1.11.5 when it comes to this? Or is e.g. 1.11.0 also bad?

[urbainvaes]

Ah good point. I just tried and the issue also occurs in 1.11.0.

[KristofferC]

Bisected to ce5fa71. You can workaround it by adding

if VERSION >= v"1.11.0-0"
  atreplinit() do repl
      repl.options.hint_tab_completes = false
  end
end

to your .julia/config/startup.jl file.

Maybe something like #56895 is needed after all? @IanButterworth

[KristofferC]

Also, I wonder if you shouldn't send this to julia as a "bracketed paste" (https://en.wikipedia.org/wiki/Bracketed-paste) instead of sending it character by character as the current script seems to do.

[IanButterworth]

Can you try 1.12 / master? It should be as fast as it is on 1.10 (or 1.11 with hints turned off) there.

Maybe something like #56895 is needed after all?

Is this entry mechanism through the bracketed paste mode?

[IanButterworth]

Ah, yeah. That should help too.

[IanButterworth]

I do think this is not an issue on master, but let me know if so.

[KristofferC]

Nightly seem to be consistently around ~300 ms with or without the tab completion on. But on ce5fa71 it is 80 ms with autocomplete off so that looks like a separate regression. Will bisect for that as well...

[KristofferC]

80ms -> 300ms regression is from 5fc5556. I am not sure why...

Looking with --trace-compile it seems there is an extra

precompile(Tuple{typeof(Base.show), Base.IOContext{Base.TTY}, Base.Multimedia.MIME{Symbol("text/plain")}, String})

that has to be precompiled after Pkg was moved out.

[urbainvaes]

Thank you very much for all the suggestions!

• Bracketed paste does improve performance on its own, but release remains slower than lts. About 50 ms for lts, vs 250 ms for release.
• The fix with if VERSION >= v"1.11.0-0" in the startup file on its own does improves performance, but only slightly: release remains slower than lts. About 600 ms for release.
• The fix with if VERSION >= v"1.11.0-0", when employed together with bracketed paste, does not improve things.

Here is the modification to use bracketed paste:

let script_bracked_paste = "\<esc>[200~".join(script, "\n")."\<esc>[201~"
vsplit | term julia
call chansend(&channel, script_bracked_paste)
startinsert