[Rd] .libPaths() on Windows may return duplicated paths

From: Henrik Bengtsson <hb_at_biostat.ucsf.edu>
Date: Tue, 15 Mar 2011 20:13:01 -0700

In R v2.12.2 patched (2011-03-13 r54787) and also in R v2.13.0 devel (2011-03-15 r54806), .libPaths() may return the multiple paths referring to the same "normalized" path name. Here is an example from Rterm --vanilla using R v2.12.2 patched:

> paths <- .libPaths(c("C:/", "C:\\"))
> paths

[1] "C:/"
[2] "C:\\"
[3] "C:/PROGRA~1/R/R-2.13.0dev/library"

The reason is that .libPaths() does not detect paths[1] and paths[2] to be "equal";

> .libPaths

function (new)

    if (!missing(new)) {

        new <- Sys.glob(path.expand(new))
        paths <- unique(path.expand(c(new, .Library.site, .Library)))
        .lib.loc <<- paths[file.info(paths)$isdir %in% TRUE]
    else .lib.loc

One solution would be to replace:

  paths <- unique(path.expand(c(new, .Library.site, .Library)))


  paths <- path.expand(c(new, .Library.site, .Library))
  paths <- utils::normalizePath(paths)
  paths <- unique(paths)

This would obviously not work because this would make .libPaths() depend on the utils package as standing. Migrating normalizePath() to the 'base' package would be one solution.

Finally, this causes update.packages() to try to download and install the same package multiple times, e.g.

> .libPaths()

[1] "C:\\Users\\hb/R/win-library/2.12"
[2] "C:/PROGRA~1/R/R-2.12.2patched/library"
[3] "C:\\Users\\hb\\R\\win-library\\2.12"

> update.packages()

digest :
 Version 0.4.1 installed in C:\Users\hb/R/win-library/2.12  Version 0.4.2 available at http://cran.stat.ucla.edu Update (y/N/c)? y
digest :
 Version 0.4.1 installed in C:\Users\hb\R\win-library\2.12  Version 0.4.2 available at http://cran.stat.ucla.edu Update (y/N/c)? y

Obviously, I know how to fix/avoid this myself, but I figured it is more generic if .libPaths() does it for everyone.


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https://stat.ethz.ch/mailman/listinfo/r-devel Received on Wed 16 Mar 2011 - 03:16:02 GMT

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