R: Problems with unloadNamespace(package) when installing a package

Question

I made an R-package called TRIMmaps and tried to install it with the command

R CMD INSTALL TRIMmaps_v1.12.0

I received the following error message:

Error in unloadNamespace(package) : 
  namespace ‘Rcpp’ is imported by ‘plyr’ so cannot be unloaded
Error in library(pkg, character.only = TRUE, logical.return = TRUE, lib.loc = lib.loc) : 
  “Rcpp” version 0.11.2 cannot be unloaded.

I do need package plyr, however, because when I remove it I get the message:

Error in loadNamespace(i, c(lib.loc, .libPaths()), versionCheck = vI[[i]]) : 
  there is no package called ‘plyr’

I removed both packages plyr and Rcpp and installed them again. My current version of Rcpp now is 0.11.5, but when I try to install the TRIMmaps-package again, I get the same error message as above including the line “Rcpp” version 0.11.2 cannot be unloaded. Although I have removed the older Rcpp-version and replaces it by 0.11.5, here still a problem occurs with 0.11.2.

How do I solve this? Any hint is appreciated.

Answer 1

I get a similar error. Minimal conditions to reproduce it seem to be:

1. Depend on a package x (in my case reshape)
2. In your vignette load a packge y (in my case plyr) that also imports or depends on x.

The vignette builds fine if you build it outside of the package building or checking process, but throws the error that you indicate otherwise. The error is also R version and maybe site specific, since it goes away with R 3.2.0 when trying to build the package on a different machine.

Answer 2

The easiest way is to close (R-Studio), or open a new (GUI), and do the job, and you can copy your code and reuse them.