Warning: strange behaviour in RStudio in R 4.5.x .

Hi Duncan,

We haven't investigated yet, but I strongly suspect this is an RStudio issue.

For extra context, RStudio is doing something similar to R's own
staged installation here, where the package is initially installed
into a _build sub-directory, and then moved to its final intended
installation location following a successful installation. This
approach can be useful on Windows because, at least in some contexts,
it's possible to move a directory from location A to location B, even
if files in location B are currently open / in-use in some
application. For RStudio, this can help avoid an installation failure
when installing a package which is already loaded in the current
RStudio R session.

In any event, would you be willing to file an issue at
https://github.com/rstudio/rstudio/issues so we can properly track and
investigate this? It will also be useful to know what version of
Windows you're using, just in case the behavior described above
depends on the Windows version being used.

Thanks,
Kevin

On Sat, Jun 28, 2025 at 12:22?PM Duncan Murdoch
<murdoch.duncan at gmail.com> wrote:

I'm running RStudio on MacOS Sonoma 14.7.1 on an M4 Macbook.  I haven't
updated either RStudio or the OS for several months.

However, I updated R to version 4.5.0 recently, and to 4.5.1 today.  In
both of those versions I'm seeing some strange behaviour when I ask
RStudio to install a package that I'm developing.  I haven't seen this
before, and I haven't noticed it in other packages.

The behaviour I see is that the package is installed
and RStudio restarts the session and runs `library(pkg)`, but it loads
the old version of the package.

I don't use the devtools option, so RStudio says it is running

   R CMD INSTALL --preclean --no-multiarch --with-keep.source pkg

If I manually restart the R session and run `library(pkg)` I get the new
one, so it appears that RStudio is loading the package before it is
fully installed.

Has anyone else seen this?  I'd especially like to know if people have
seen it outside of RStudio.  I suspect it's a bug there, but as I said,
I haven't updated it recently.

BTW, I think I know how to stop this in RStudio:  In the "Global Options
| Packages | Development" dialog, there's an option "Use alternate
library path when building package".

If checked, this builds to


/Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/library/_build

instead of to

   /Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/library

then moves the package into place afterwards.  I've only seen the
strange behaviour when I have that option checked, which is what makes
me think this is an RStudio bug --- but somehow triggered by something
new in R 4.5.x.

Duncan Murdoch