Windows path conflict: %localappdata%/R/cache/R/renv/index

[AlexTate]

A colleague recently ran into an issue installing packages in an renv managed environment on Windows 11. They reported that the following error was produced for any package installation, but for this particular output we were attempting to install workflowr:

> install.packages("workflowr")
# Downloading packages -------------------------------------------------------
Warning: failed to create directory at path 'C:\Users\user\AppData\Local/R/cache/R/renv/index/R-4.2/x86_64-w64-mingw32/available-packages'
Warning in entry[[key]] : wrong arguments for subsetting an environment
Warning: failed to create directory at path 'C:\Users\user\AppData\Local/R/cache/R/renv/index/R-4.2/x86_64-w64-mingw32/available-packages'
Warning in file.path(repo, "src/contrib/Archive", Package) :
  object 'Package' not found
Error: failed to retrieve package ''

We found that this was because the directory C:\Users\user\AppData\Local/R/cache/R/renv already contained an INDEX file typical of R package structure, and since Windows treats paths as case-insensitive, the intermediate directory index couldn't be created. After renaming the resident file to _INDEX all installations proceeded without issue.

[kevinushey]

Are you still seeing this (or related) issues? I can't see why the presence of the index directory in the renv root folder could matter here.

[AlexTate]

@kevinushey they reported no further issues with installation after the rename. The issue is that renv appears to create the index directory in %localappdata%/R/cache/R/renv while downloading packages. Is that the intended behavior, or does that sound like the result of a misconfiguration? If the behavior is intentional it matters because there's already an INDEX file in that location, so it is a path conflict to also create an index directory there since:

1. Directories are essentially files and you can't have a file and directory share a name in the same path
2. index == INDEX as far as Windows is concerned because paths are case-insensitive

If you're testing this issue on linux/mac, I'd expect the error to be absent since they use case-sensitive paths so index != INDEX

[kevinushey]

The issue is that renv appears to create the index directory in %localappdata%/R/cache/R/renv while downloading packages.

That is intentional, but it's not clear to me where this INDEX file is coming from. This directory and its contents should be managed by renv, and I'm not sure why an INDEX file is being created here.

[kevinushey]

R does create an INDEX file when building a package, e.g. from:

https://github.com/wch/r-source/blob/225050624227afe43a0b1ae2ec597cad10eac874/src/library/tools/R/admin.R#L473-L481

but it would be surprising to me if that cache directory were being selected during package installation. Basically, I'm curious if you know why that INDEX file was created in the first place at that location.

[AlexTate]

why that INDEX file was created in the first place at that location.

That does seem to be the crux of the issue. I finally dusted off my old Windows 10 partition in order to take a look at a fresh install. My report is complicated by the fact that I only recently started working with with the user who reported this issue, I haven't been a Windows user in a long time, and (worst of all) I have no prior experience with renv. I realize that none of that is very helpful and I apologize; I'll do my best to explain my observations but I have no expectations of a solution from the incomplete info I have.

As far as I can tell, somehow the contents of the renv package were already present in that directory. The resident INDEX file preventing the creation of index/ was actually from renv's own package contents. It's as though renv had been installed in %localappdata%/R/cache/R/renv instead of %localappdata%/R/win-library/4.2/renv. Whether that was from user action or a bug, I couldn't say.

What I CAN say is that I'm not observing the same from a fresh installation. I'm not seeing renv's package contents in %localappdata%/R/cache/R/renv. I'll see if I can gather more info and will update this thread as it becomes available.