changing the default package cache dir using env var?

[achubaty]

Setting env var R_REQUIRE_PKG_CACHE=/mnt/shared_cache/Require/packages does not properly create the directory structure of the default package cache directory.
Specifically, I would expect that the R version (4.3 here) would be automatically appended to the path, rather than relying on the user to actively maintain and update their ~/.Renviron file to manually specify the R version (which also prevents multiple versions of R being used on the same machine).

d> getOption("Require.RPackageCache")
[1] "default"
d> RequirePkgCacheDir(FALSE)
  /home/achubaty/.cache/R/Require/packages/4.3 
"/home/achubaty/.cache/R/Require/packages/4.3" 
d> Require::getOptionRPackageCache()
[1] "/mnt/shared_cache/Require/packages"

[eliotmcintire]

This works now, as expected (with updated function names that start with cache...

> getOption("Require.RPackageCache")
NULL
> cachePkgDir(FALSE)
  /home/emcintir/.cache/R/Require/packages/4.3 
"/home/emcintir/.cache/R/Require/packages/4.3" 
> cacheGetOptionCachePkgDir()
  /home/emcintir/.cache/R/Require/packages/4.3 
"/home/emcintir/.cache/R/Require/packages/4.3" 

[achubaty]

Not working with Require 1.0.1

# ~/.Renviron
R_REQUIRE_PKG_CACHE=/mnt/shared_cache/Require/packages

> Require::cacheGetOptionCachePkgDir()
[1] "/mnt/shared_cache/Require/packages"

[achubaty]

UPDATE: using latest development branch (4d4cea9, which includes fixes for #124), this is still not working correctly:

# ~/.Renviron
R_REQUIRE_PKG_CACHE=/mnt/shared_cache/Require/packages

d> cachePkgDir(FALSE)
  /home/achubaty/.cache/R/Require/packages/4.5 
"/home/achubaty/.cache/R/Require/packages/4.5" 
d> cacheGetOptionCachePkgDir()
[1] "/mnt/shared_cache/Require/packages"

I think this is because cachePkgDir() uses cacheDir() (which consults R_REQUIRE_CACHE) instead of checking R_REQUIRE_PKG_CACHE.

[achubaty]

there are several mechanisms in the current package to get the package cache directory, and they are not consistent with one another:

• cacheGetOptionCachePkgDir(): seems to be the most commonly used, but it doesn't append the R version to the path -- from its name, it should only be used to check the option and env var (so it would make sense to call it from cachePkgDir());
• cachePkgDir(): I would expect this should be used throughout, as it appends the R version to the path, but it is used less frequently than cacheGetOptionCachePkgDir(), suggesting a more ad hoc approach to getting the path (with R version) from each of the functions where it is used;
• Require:::rpackageFolder(): also appends the R version to the path, but it's not clear why this is being used instead of cachePkgDir();

untangling this (started on branch 91-pkgCachePath-envvar) will require further discussion