Can renv be used to create a virtual environment with a specific version of R?

Question

I recently installed R 4.0, after previously using relying R 3.6.3. To manage R repositories, I use Rstudio (currently 1.2.5042 on a Windows 10 machine). After upgrading to R 4.0, I opened a project from a few months ago, and realized that Rstudio is now, by default, using the newer version of R (and it's library folder). When running renv::restore(), renv attempts to re-install all libraries in the .lock file for the newer version of R, and I don't see any way to specify that I want to keep using R 3.6.3 and it's associated library.

Coming from a python background, I had assumed that renv would create a virtual environment that isolates both the interpreter and the libraries that the project uses (similar to how anaconda environments are created). However, after looking through the documentation and doing a few searches, I have found no reference to isolating a particular version of R. I have, however, found that Rstudio defaults to using the latest version of R, which is not necessarily the behaviour that I want.

I have tried using anaconda to manage an R environment. However, Anaconda relies on its own smaller repository of R packages, and many of the libraries I need are from researchers that house their code on GitHub.

Is there a way to create an R environment in which I can isolate both the R libraries and the version of R itself? Or, perhaps there is something I am missing about how environments with R/Rstudio are intended to be used?

Answer 1

You are correct that renv only manages the installed R packages, and not the R interpreter itself.

Depending on how you're using RStudio, you can still "fake" this by setting the RSTUDIO_WHICH_R environment variable. For example:

export RSTUDIO_WHICH_R=/path/to/R
rstudio

would tell RStudio to "bind" to the version of R specified by the RSTUDIO_WHICH_R environment variable.

For what it's worth, the ability to bind projects to a specific version of R is a feature of the professional editions of RStudio; however, it's not available in the open-source version. See here for more details.