wd() fails without paramater path

[thomaskern]

Function wd() throws an exception when parameter path is left untouched, even inside a package.

setwd("~/ggplot2")
wd()

results in

> wd()
Error in if (!file.exists(path)) { : argument is of length zero
> traceback()
1: wd()

On the other hand, passing an empty character vector works:

wd(path="")
Changing working directory to /Users/bosie/ggplot2/

I would argue that according to the docs, this behavior is not expected. If it is, the default value NULL for parameter path should be removed and path should not be optional but mandatory.

Setup:

> sessionInfo()
R version 3.0.2 (2013-09-25)
Platform: x86_64-apple-darwin10.8.0 (64-bit)

locale:
[1] en_GB.UTF-8/en_GB.UTF-8/en_GB.UTF-8/C/en_GB.UTF-8/en_GB.UTF-8

attached base packages:
[1] graphics  grDevices utils     datasets  stats     methods   base     

other attached packages:
 [1] ggHorizon_0.1      roxygen2_2.2.2     digest_0.6.3       proto_0.3-10       RColorBrewer_1.0-5
 [6] plyr_1.8           maps_2.3-6         devtools_1.3       ggplot2_0.9.3.1.99 vimcom.plus_0.9-9 

loaded via a namespace (and not attached):
 [1] brew_1.0-6       colorspace_1.2-4 dichromat_2.0-0  evaluate_0.5.1   grid_3.0.2       gtable_0.1.2    
 [7] httr_0.2         labeling_0.2     MASS_7.3-29      memoise_0.1      munsell_0.4.2    parallel_3.0.2  
[13] RCurl_1.95-4.1   reshape2_1.2.2   scales_0.2.3     stringr_0.6.2    tools_3.0.2      whisker_0.3-2