On 2026-03-09 11:39 a.m., Serguei Sokol via R-devel wrote:
Le 09/03/2026 à 12:53, Tim Taylor a écrit :
I appreciate there are likely many places where calling a stats function via
`::` and without the stats package being loaded could be problematic but would
R core have any interest in adapting functions to accommodate this where
possible?
The example I ran in to today can be seen below:
ex <- function() {
counts <- c(18,17,15,20,10,20,25,13,12)
outcome <- gl(3,1,9)
treatment <- gl(3,3)
stats::glm(counts ~ outcome + treatment, family = "poisson")
}
tools::R(ex)
#>
#> Call: stats::glm(formula = counts ~ outcome + treatment, family = "poisson")
#>
#> Coefficients:
#> (Intercept) outcome2 outcome3 treatment2 treatment3
#> 3.045e+00 -4.543e-01 -2.930e-01 6.972e-16 8.237e-16
#>
#> Degrees of Freedom: 8 Total (i.e. Null); 4 Residual
#> Null Deviance: 10.58
#> Residual Deviance: 5.129 AIC: 56.76
tools::R(ex, env=c("R_DEFAULT_PACKAGES=NULL"))
#> Error: error in inferior call:
#> object 'poisson' of mode 'function' was not found
The second call fails due to the following line in glm:
if (is.character(family))
family <- get(family, mode = "function", envir = parent.frame())
A non-breaking patch (AFAICT) could add an additional branch that explicitly
searches a lookup of functions in the stats package if the above call to `get`
failed.
You can do it on your own side by modifying the function 'ex' like:
ex <- function() {
counts <- c(18,17,15,20,10,20,25,13,12)
outcome <- gl(3,1,9)
treatment <- gl(3,3)
require(stats)
stats::glm(counts ~ outcome + treatment, family = "poisson")
}
Note "require(stats)" before glm() call. In a classical R env, this is almost a
no-cost operation because stats is already attached and in R_DEFAULT_PACKAGES=NULL
case, it does what you need.
That's a relatively harmless thing to do in your own scripts, but you
shouldn't do that in a package that you expect others to use. There may
be a reason they don't have stats on the search list, and that puts it
there.
Duncan Murdoch
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