[R-pkg-devel] Do I need to namespace and import functions from 'methods' package?

Duncan Murdoch murdoch.duncan at gmail.com
Sun Jul 12 22:36:09 CEST 2015

On 12/07/2015 4:01 PM, Dean Attali wrote:
> I have a package that is using the 'is' function from the 'methods'
> package.  My package has been on CRAN for some time now and has had 3
> different versions already. Yesterday when submitting, I got a response
> with:
> * checking R code for possible problems ... NOTE
>> ggMarginal: no visible global function definition for 'is'
>> Undefined global functions or variables:
>>   is
> So I fixed it by changing 'is' to 'methods::is', and then I got a response
> * checking dependencies in R code ... WARNING
>> '::' or ':::' import not declared from: ‘methods’
> So I suppose I need to declare 'methods' in my imported packages.
> My question is: is this a new requirement, to explicitly import 'methods'
> and namespace functions from it, or has it always been a requirement but I
> just wasn't caught? Or is it not even a requirement and the R CMD check was
> being weird?

It is a new requirement.  As Joshua Ulrich posted on Friday,

> Yes, this is expected.  See:
> http://developer.r-project.org/blosxom.cgi/R-devel/NEWS/2015/06/29#n2015-06-29
> And an earlier email on this list:
> https://stat.ethz.ch/pipermail/r-package-devel/2015q2/000171.html

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