[R-pkg-devel] NOTE in r-devel-linux-x86_64-fedora-clang

[Duncan Murdoch]

On 07/08/2020 11:02 a.m., Brian G. Peterson wrote:
> 
> On Fri, 2020-08-07 at 15:46 +0100, Gábor Csárdi wrote:
>> If you want to link to a package in the documentation, you'll have to
>> add it to Suggests.
> 
> This doesn't make any sense.  If you don't use the code from that
> package anywhere, then a cross-reference to that package should not
> require the extra dependency in Suggests.
> 
> Cross references should be able to point to other functionality that
> might be useful to the user, or might add extra depth of understanding
> to a concept.  If the user doesn't have the package installed, no
> worries, it is just a cross reference.
> 
> The requirement you are suggesting is also not discussed in Writing R
> Extensions:
> 
> https://cran.r-project.org/doc/manuals/r-patched/R-exts.html#Cross_002dreferences
> 
> In fact, it explicitly allows links to potentially uninstalled
> packages.

You're reading the wrong version of the manual.  This is in the R-devel 
manual:

"Packages referred to by these ‘other forms’ should be declared in the 
DESCRIPTION file, in the ‘Depends’, ‘Imports’, ‘Suggests’ or ‘Enhances’ 
fields. "

This is at the end of section 2.5 in 
https://cran.r-project.org/doc/manuals/r-devel/R-exts.html.

Duncan Murdoch