R 4.6.0: Session watcher not working

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

JupyterLab: Click on 'code-server'
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"

R 4.6.0 causes radian to crash on startup:

@randy3k

Ping @randy3k

@benz0li

@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.

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

@MalditoBarbudo

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.

@benz0li

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().

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:

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()
}

I removed the regular brew version of R: brew uninstall R
I switched over to rig: brew tap r-lib/rig && brew install --cask rig
I added and switched to 4.5: rig add 4.5 && rig list && rig switch 4.5-arm64
I installed the extension from .vsix file via Tag v0.4.0
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:

I am working on the 3.0.0 release,
3.0.0-rc1 can be find at https://github.com/REditorSupport/vscode-R/releases/tag/latest

it should fix this issue.

@Skolmeister

I attempted building the extension, did not resolve the issue, maybe I did it wrong or using the wrong branch (master).

However, implementing @Skolmeister 's solution worked.

@Skolmeister

The 3.0.0-rc1 version does seem to fix the issue, however I encountered a bug when running View(...) in a debugging context.

After more testing, @Skolmeister's suggestion seems to work for extension version 2.8.8 with R version 4.6.0.

Had the same issue after updating R from 4.5.2 to 4.6.0. .vsc.attach() could not be found anymore.

The root cause is that R 4.6.0 no longer calls .First.sys() during startup. The extension's init.R relies on overwriting .First.sys to initialize the session watcher, so the attach function never gets defined.

Fix that worked for me (in init.R of the extension, for me located at ~/.windsurf/extensions/reditorsupport.r-2.8.8-universal/R/session/init.R):

Change the assign call from .First.sys to .First:

- assign(".First.sys", init_last, envir = globalenv())
+ assign(".First", init_last, envir = globalenv())

Remove the old.First.sys lines:

- old.First.sys <- .First.sys

and inside init_last:

- old.First.sys()

Update the cleanup at the end of init_last:

- rm(".First.sys", envir = globalenv())
+ rm(".First", envir = globalenv())

After restarting the R terminal everything attaches correctly again. This should probably be patched in the extension since R 4.6.0 deprecated .First.sysentirely.

The .First.sys() fix is working for me too but I was unable to implement it in .Rprofile. Waiting on a more permanent solution. Thanks all!

The .First.sys() fix is working for me too but I was unable to implement it in .Rprofile. Waiting on a more permanent solution. Thanks all!

What do you mean by "unable to implement it in .Rprofile". Whats happening and what would you expect?

The .First.sys() fix is working for me too but I was unable to implement it in .Rprofile. Waiting on a more permanent solution. Thanks all!

What do you mean by "unable to implement it in .Rprofile". Whats happening and what would you expect?

I tried to put the ".First.sys()" into .Rprofile so that it would run when an active R terminal was opened in VS code without me manually typing and setting it, but it didn't register. I am still writing it into the terminal for it to attach.

This has already been resolved in main, so I'll close it (I'll pin it instead).
The 3.0.0 release is being tracked in #1727.

Version 3.0.0 has been released.

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R 4.6.0: Session watcher not working #1696

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R 4.6.0: Session watcher not working #1696

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benz0li commented on Apr 27, 2026

benz0li commented on Apr 28, 2026

MalditoBarbudo commented on Apr 29, 2026

benz0li commented on Apr 29, 2026

Skolmeister commented on Apr 29, 2026

eitsupi commented on Apr 29, 2026

TinasheMTapera commented on Apr 30, 2026

randy3k commented on May 2, 2026

MartinMorlot commented on May 18, 2026

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