[Rd] instantiating a reference class with an initialize() method from .onLoad fails

Martin Morgan mtmorgan at fhcrc.org
Fri Feb 21 04:41:04 CET 2014

PkgA has a single R/binding.R file containing

    .A <- setRefClass("A", methods=list(initialize=function(...) {}))
    .onLoad <- function(...) .A()




     Package: PkgA
     Type: Package
     Title: Documenting reference classes
     Version: 0.0.1
     Date: 2012-08-05
     Author: Martin Morgan
     Maintainer: Martin Morgan <mtmorgan at fhcrc.org>
     Description: This package implements a simple 'reference' class
     Depends: methods
     Imports: methods
     License: Apache License 2.0
     Collate: binding.R

R CMD INSTALL PkgA results in

p$ R --vanilla CMD INSTALL PkgA
* installing to library ‘/home/mtmorgan/R/x86_64-unknown-linux-gnu-library/3.1’
* installing *source* package ‘PkgA’ ...
** R
** preparing package for lazy loading
** help
No man pages found in package  ‘PkgA’
*** installing help indices
** building package indices
** testing if installed package can be loaded
Error : .onLoad failed in loadNamespace() for 'PkgA', details:
   call: initialize(value, ...)
   error: attempt to apply non-function
Error: loading failed
Execution halted
ERROR: loading failed
* removing ‘/home/mtmorgan/R/x86_64-unknown-linux-gnu-library/3.1/PkgA’
* restoring previous ‘/home/mtmorgan/R/x86_64-unknown-linux-gnu-library/3.1/PkgA’

Having read


I used

     setLoadAction(function(nmspc) .A())

in place of .onLoad, and had success. However, a more complicated scenario,


where a data file contains an instance of a class defined in a package that 
imports PkgA, fails during R CMD check or in an R session with

     env = new.env(); load("data.Rdata", env); get("data", env)

including when .A() is eval() or evalq()'d in envir=nmspc.

Thanks for any hints.

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