[R-pkg-devel] Should 'methods' be in Imports?

[Duncan Murdoch]

On 16/03/2023 2:21 p.m., Noah Greifer wrote:
> 
> Thank you for your input. /broom/, /mlogit/, /twang/, and /Hmisc/ 
> are examples of major packages that import functions from /stats/, 
> /utils/, /graphics/, or other base packages but don't include them in 
> the DESCRIPTION. All of my packages (/cobalt/, /WeightIt/, /MatchIt/) do 
> too, and I have never had a message from CRAN about it. (None of these 
> are specifically about /methods/, but as a base package I assume it 
> should work the same as these others.)
> 

broom doesn't mention stats in DESCRIPTION, but does import from it in 
the NAMESPACE. (I haven't checked the rest of your list.)  I'm a little 
surprised by that, but it's understandable:  the NAMESPACE does declare 
that stats is needed.  WRE says this about Imports:

"Namespaces accessed by the ‘::’ and ‘:::’ operators must be listed 
here, or in ‘Suggests’ or ‘Enhances’ (see below). Ideally this field 
will include all the standard packages that are used, and it is 
important to include S4-using packages."

So the use of Imports for "standard packages" that are used in NAMESPACE 
appears to be optional but recommended.

However, my understanding was that you were talking about using things 
like graphics::abline without importing any graphics functions via the 
NAMESPACE; in that case, the manual is very explicit that you would need 
to put graphics in Imports.  That doesn't mean "R CMD check" will 
complain if you don't, but it does mean that it might start doing so if 
it doesn't already.

Do you know of any examples of packages that use things like 
graphics::abline without mentioning graphics in either the NAMESPACE or 
DESCRIPTION file?

Duncan Murdoch