R 4.6.0: Session watcher not working

[benz0li]

Describe the bug

'R: Creating R Terminal' results in 'R: (not attached)'.

To Reproduce

On a host with docker installed:

docker run --rm -p 8888:8888 -ti glcr.b-data.ch/jupyterlab/r/base:4.6.0

Follow the instructions in the terminal, i.e. open URL http://127.0.0.1:8888/lab?token=${TOKEN} in a browser.

Inside the container

1. JupyterLab: Click on 'code-server'
2. code-server: Open View > Command Palette... > R: Create R Terminal

Can you fix this issue by yourself? (We appreciate the help)

No

(If applicable) Please attach setting.json

"r.plot.useHttpgd": true,
"r.rterm.linux": "/usr/local/bin/R",
"r.rterm.option": [
  "--no-save",
  "--no-restore"
],
"r.workspaceViewer.showObjectSize": true,

Expected behavior

Session watcher also works with R 4.6.0 and later.

Screenshots

-

Environment (please complete the following information):

• OS: Linux (Debian 13)
• code-server Version: 4.117.0
  • aka Code Version 1.117.0
• R Version: 4.6.0
• vscode-R version: 2.8.8

Additional context

R version 4.6.0 (2026-04-24) -- "Because it was There"
Copyright (C) 2026 The R Foundation for Statistical Computing
Platform: aarch64-unknown-linux-gnu

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

  Natural language support but running in an English locale

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> .vsc.attach()
Error in .vsc.attach() : could not find function ".vsc.attach"

[benz0li]

R 4.6.0 causes radian to crash on startup:

• Can not start with R 4.6, cannot load symbol TRUELENGTH randy3k/radian#528
• Please update to ensure compatibility with R 4.6.0 and later randy3k/rchitect#41

[benz0li]

Ping @randy3k

[MalditoBarbudo]

@benz0li

Having the same problem.
I found a workaround looking at ~/.vscode/extensions/reditorsupport.r-2.8.8/R/session/init.R code. It seems like the code is correctly sourced and functions are attached, but the new .First.sys() is never called. Running it in the R console will attach the R session.

[benz0li]

It seems like the code is correctly sourced and functions are attached, but the new .First.sys() is never called.

A similar problem was reported for arf:

• attaching to vscode eitsupi/arf#157
  • .First() and .First.sys() are bypassed during the startup sequence eitsupi/arf#158

[Skolmeister]

Good call @MalditoBarbudo, I edited my .Rprofile to call the function explicitely and now it works without manual interference:

if (interactive() && Sys.getenv("RSTUDIO") == "") {
  init_path <- file.path(Sys.getenv(if (.Platform$OS.type == "windows") "USERPROFILE" else "HOME"), ".vscode-R", "init.R")
  source(init_path)
  # Workaround .vsc.attach()
  .First.sys()
}

For me this is good enough as a workaround for the moment.

[eitsupi]

Good point @benz0li cc @bsirak
It seems that it now works as documented (See ?Startup).

Currently, vscode-R behaves in a way that depends on the implementation details and does not adhere to the correct specifications.
Should use .First() instead of .First.sys().

[TinasheMTapera]

The weirdest thing just happened: I was perusing google after experiencing this issue and noticed this VSCode Extension hiding in the interwebs: https://github.com/WahiduzzamanKhan/rig-manager-vscode, and somehow, my problem went away. I mainly just wanted to install this extension first just for kicks:

0. I had my project R profile and home dir R profile like this:

# project
if (interactive() && Sys.getenv("RSTUDIO") == "") {
  init_path <- file.path(Sys.getenv(if (.Platform$OS.type == "windows") "USERPROFILE" else "HOME"), ".vscode-R", "init.R")
  source(init_path)
}

# home dir
if (interactive() && Sys.getenv("RSTUDIO") == "") {
  init_path <- file.path(Sys.getenv(if (.Platform$OS.type == "windows") "USERPROFILE" else "HOME"), ".vscode-R", "init.R")
  source(init_path)
  # Workaround .vsc.attach()
  .First()
}

1. I removed the regular brew version of R: brew uninstall R
2. I switched over to rig: brew tap r-lib/rig && brew install --cask rig
3. I added and switched to 4.5: rig add 4.5 && rig list && rig switch 4.5-arm64
4. I installed the extension from .vsix file via Tag v0.4.0
5. Vscode automagically configured itself and a new terminal opened all by itself

Someone smarter than me might be able to use this info!

Edit: still not perfect as the session hasn't fully "attached," but it's a little better: