[R-pkg-devel] using a class from a suggested package

[Thierry Onkelinx]

Dear all,

My package A defines an S4 method for the "inla" S3 class. The INLA package
defines this class. That package has a huge source, making the build fail
on r-universe.dev. The solution is to not importClassesFrom(INLA, inla) but
use setOldClass("inla"). Then I can list INLA under Suggests instead of
Imports. So far so good.

My package B defines S4 objects with a superclass "maybeINLA" defined
as setClassUnion("maybeInla", c("inla", "NULL")). It also imports the
method from package A which handles the "inla" class. This is where I'm
gettin stuck.
- importClassesFrom(INLA, inla) works, but then I can't Suggests INLA.
- using setOldClass("inla") yields an R CMD check warning: "class "inla" is
defined (with package slot ‘A’) but no metadata object found to revise
superClass information---not imported?  Making a copy in package ‘B’ "
- having exportClasses(inla) in package A and importClassesFrom(A, inla) in
package B works but this displays the message "Found more than one class
"inla" in cache; using the first, from namespace 'A' Also defined by 'INLA'
".

How can I use the "inla" class in package B while Suggesting the INLA
package and not have the warnings/messages?

Best regards,

ir. Thierry Onkelinx
Statisticus / Statistician

Vlaamse Overheid / Government of Flanders
INSTITUUT VOOR NATUUR- EN BOSONDERZOEK / RESEARCH INSTITUTE FOR NATURE AND
FOREST
Team Biometrie & Kwaliteitszorg / Team Biometrics & Quality Assurance
thierry.onkelinx using inbo.be
Havenlaan 88 bus 73, 1000 Brussel
www.inbo.be

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