BUG(?): Function with class attribute set becomes \keyword{datasets} Rd document

[HenrikBengtsson]

Problem

I'm trying to add a class attribute to a function, but when I do, roxygen2 5.0.1 gets confused and documents it as an R object. For example:

#' Foo function
#'
#' @export
foo <- function() TRUE
class(foo) <- "foo"

generates

% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/foo.R
\docType{data}
\name{foo}
\alias{foo}
\title{Foo function}
\format{An object of class \code{foo} of length 1.}
\usage{
foo
}
\description{
Foo function
}
\keyword{datasets}

Workaround

By making sure the class attribute also contains "function", it seems to work, e.g.

#' Foo function
#'
#' @export
foo <- function() TRUE
class(foo) <- c("foo", "function")

becomes

% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/foo.R
\name{foo}
\alias{foo}
\title{Foo function}
\usage{
foo()
}
\description{
Foo function
}

Troubleshooting

Could it be that roxygen2 identifies functions using inherits(x, "function") rather than is.function(x)? For example:

> foo <- function() TRUE; class(foo) <- "foo"
> inherits(foo, "function")
[1] FALSE
> is.function(foo)
[1] TRUE