[Rd] Never exporting .__global__ and .__suppressForeign__?

[Ivan Krylov]

Hello,

(Dear Richard, I hope you don't mind being Cc:'d on this thread in
R-devel. This is one of the ways we can prevent similar problems from
happening in the future.)

Sometimes, package authors who use both exportPattern('.') and
utils::globalVariables(...) get confusing WARNINGs about undocumented
exports:
https://stat.ethz.ch/pipermail/r-package-devel/2024q1/010531.html

I would like to suggest adding the variables used by
utils::globalVariables and utils::suppressForeignCheck to the list of
things that should never be exported:

Index: src/library/base/R/namespace.R
===================================================================
--- src/library/base/R/namespace.R	(revision 86054)
+++ src/library/base/R/namespace.R	(working copy)
@@ -806,7 +806,8 @@
         if (length(exports)) {
             stoplist <- c(".__NAMESPACE__.", ".__S3MethodsTable__.",
                           ".packageName", ".First.lib", ".onLoad",
-                          ".onAttach", ".conflicts.OK", ".noGenerics")
+                          ".onAttach", ".conflicts.OK", ".noGenerics",
+                          ".__global__", ".__suppressForeign__")
             exports <- exports[! exports %in% stoplist]
         }
 	if(lev > 2L) message("--- processing exports for ", dQuote(package))

(Indeed, R CMD check is very careful to only access these variables
using the interface functions in the utils package, so there doesn't
seem to be any code that depends on them being exported, and they
usually aren't.)

Alternatively (or maybe additionally), it may be possible to enhance
the R CMD check diagnostics by checking whether the name of the
undocumented object starts with a dot and asking the user whether it
was intended to be exported. This is not as easy to implement due to
tools:::.check_packages working with the log output from
tools::undoc(), not the object itself. Would a change to
tools:::format.undoc be warranted?

-- 
Best regards,
Ivan