[Rd] validObject throws non-caught error when slot doesn't exist

From: Patrick Aboyoun <paboyoun_at_fhcrc.org>
Date: Thu, 18 Jun 2009 16:42:37 -0700

I have been retooling an S4 class definition to include another slot and have found that the methods::validObject function (defined in methods/R/SClasses.R) in R-devel throws an error that isn't caught internally (and thus not controllable by 'test' argument) when retrieving a non-existent slot. The offending line of code is shown below:

> validObject

function (object, test = FALSE, complete = FALSE) {

    for (i in seq_along(slotTypes)) {

        classi <- slotTypes[[i]]
        sloti <- slot(object, slotNames[[i]]) # offending line of code

One potential patch is to substitute the offending line with

        sloti <- try(slot(object, slotNames[[i]]), silent = TRUE)
        if (class(sloti) == "try-error") {
            errors <- c(errors, paste("missing slot \"", slotNames[[i]],
                "\"", sep = ""))

Here is a reproduce and an example using vaildObject2 that substitutes the offending line with the code given above:

> setClass("Foo", representation(bar = "character"))
[1] "Foo"
> a <- new("Foo", bar = letters)
> setClass("Foo", representation(bar = "character", star = "numeric"))
[1] "Foo"
> validObject(a, test = TRUE)

Error in slot(object, slotNames[[i]]) :
  no slot of name "star" for this object of class "Foo"
> validObject2(a, test = TRUE)

[1] "missing slot \"star\""
> sessionInfo()

R version 2.10.0 Under development (unstable) (2009-06-12 r48755) i386-apple-darwin9.6.0

[1] en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats graphics grDevices utils datasets methods base


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https://stat.ethz.ch/mailman/listinfo/r-devel Received on Thu 18 Jun 2009 - 23:49:16 GMT

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