imodify drops the list name for a single element list

[ahjames11]

For a single element list, imodify() is dropping the list name. Here is a 2 element list, which returns what I would expect.

library(purrr) # version 0.3.4
library(dplyr)

mtcars1 <- mtcars[1, 1:2]
mtcars2 <- mtcars[2, 1:2]

# multi element list
x <- lst(mtcars1, mtcars2)

# okay
imodify(x, ~ mutate(.x, mpg = log(mpg)))
#> $mtcars1
#>                mpg cyl
#> Mazda RX4 3.044522   6
#> 
#> $mtcars2
#>                    mpg cyl
#> Mazda RX4 Wag 3.044522   6

I would expect the single element list to provide the name as well. But it is unnamed ([[1]]). You do get the list name with modify().

# single element list
y <- x[1]

# unexpected
imodify(y, ~ mutate(.x, mpg = log(mpg)))
#> [[1]]
#>                mpg cyl
#> Mazda RX4 3.044522   6

# okay
modify(y, ~ mutate(.x, mpg = log(mpg)))
#> $mtcars1
#>                mpg cyl
#> Mazda RX4 3.044522   6

^{Created on 2021-06-04 by the reprex package (v2.0.0)}

[hadley]

Somewhat more minimal reprex:

library(purrr)
x <- list(x = 10, y = 20)
str(imodify(x, \(x, y) y))
#> List of 2
#>  $ x: chr "x"
#>  $ y: chr "y"
str(imodify(x[1], \(x, y) x * 2))
#> List of 1
#>  $ : num 20

^{Created on 2022-08-23 by the reprex package (v2.0.1)}

[hadley]

Also part of #878