Dear Kevin, As others have mentioned, it's my sense that this kind of error has become more frequent -- at least I see students who encounter these errors more frequently. I agree that a less cryptic error message might help.
Best, John -------------------------------------- John Fox, Professor McMaster University Hamilton, Ontario, Canada Web: socserv.mcmaster.ca/jfox > -----Original Message----- > From: R-devel [mailto:r-devel-boun...@r-project.org] On Behalf Of Kevin > Ushey > Sent: Monday, October 24, 2016 1:51 PM > To: R-devel <r-devel@r-project.org> > Subject: [Rd] improve 'package not installed' load errors? > > Hi R-devel, > > One of the more common issues that new R users see, and become stumped > by, is error messages during package load of the form: > > > library(ggplot2) > Error in loadNamespace(j <- i[[1L]], c(lib.loc, .libPaths()), > versionCheck = vI[[j]]) : > there is no package called 'Rcpp' > Error: package or namespace load failed for 'ggplot2' > > Typically, error messages of this form are caused simply by one or more > dependent packages (in this case, 'Rcpp') not being installed or > available on the current library paths. (A side question, which I do not > know the answer to, is how users get themselves into this state.) > > I believe it would be helpful for new users if the error message > reported here was a bit more direct, e.g. > > > library(ggplot2) > Error: 'ggplot2' depends on package 'Rcpp', but 'Rcpp' is not installed > consider installing 'Rcpp' with install.packages("Rcpp") > > In other words, it might be helpful to avoid printing the > 'loadNamespace()' call on error (since it's mostly just scary / > uninformative), and check up-front that the package is installed before > attempting to call 'loadNamespace()'. I'm sure a number of novice users > will still just throw their hands up in the air and say "I don't know > what to do", but I think this would help steer a number of users in the > right direction. > > (The prescription to suggest installing a package from CRAN if available > might be a step too far, but I think making it more clear that the error > is due to a missing dependent package would help.) > > Any thoughts? > Kevin > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
