dots_list() inconsistency with splicing and unnamed arguments in homonym check.

[jpryby]

When using the .named=TRUE argument, the homonym check will fail to catch issues if the same set of arguments are passed as a spliced list that would fail if passed directly, leading to users having to add a secondary check if homonyms are not allowed. This seems to occur when the argument being passed is a variable.

reprex below.

library(rlang)
packageVersion("rlang")
#> [1] '1.1.4'

R.version$version.string
#> [1] "R version 4.4.1 (2024-06-14 ucrt)"


df <- data.frame()
named_list <- list(a=df,b=df)
unnamed_list <- unname(named_list)
basic_list <- list(1,2,3)

identical(
    dots_list(!!!named_list), 
    dots_list(a=df,b=df)
)
#> [1] TRUE

identical(
    dots_list(!!!unnamed_list), 
    dots_list(df,df)
)
#> [1] TRUE

identical(
    dots_list(!!!unnamed_list, .named=TRUE), 
    dots_list(df,df, .named=TRUE)
)
#> [1] FALSE

dots_list(!!!unnamed_list, .named=TRUE, .homonyms= "error")
#> $`<df[,0]>`
#> data frame with 0 columns and 0 rows
#> 
#> $`<df[,0]>`
#> data frame with 0 columns and 0 rows

try(dots_list(df,df, .named=TRUE, .homonyms= "error"))
#> Error : Arguments in `...` must have unique names.
#> ✖ Multiple arguments named `df` at positions 1 and 2.

dots_list(!!!basic_list, .named=TRUE, .homonyms= "error")
#> $`1`
#> [1] 1
#> 
#> $`2`
#> [1] 2
#> 
#> $`3`
#> [1] 3

try(dots_list(1,2,3, .named=TRUE, .homonyms= "error"))
#> $`1`
#> [1] 1
#> 
#> $`2`
#> [1] 2
#> 
#> $`3`
#> [1] 3

^{Created on 2024-08-14 with reprex v2.1.0}