[Tikzdevice-bugs] Use of Sys.which() map not give "" if the command is not found

[Prof Brian Ripley]

This concerns packages

adimpro cacher gdata gnumeric highlight maptools runjags skmeans 
tikzDevice

It looks like you have not consulted the Value section of the current 
help page for Sys.which:

Value:

      A character vector of the same length as ‘names’, named by
      ‘names’.  The elements are either the full path to the
      executable/script or some indication that no executable of that
      name was found.  Typically the indication is ‘""’, but this does
      depend on the OS (and is a message on Solaris).

So you need an additional check that the result actually is a command 
(e.g. via file.exists).

Can we please have an update addressing this.

(It is likely that Sys.which will be changed in future to incorporate 
this check, but package changes are still needed to work with current 
and earlier versions of R.)

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595