Incorrect evaluation of tidyselect expressions inside functions?

[catalamarti]

So for me the following behavior is not expected... Any thought?
For what I've seen the name value inside the function changes its value to the position of the selected columns in the first evaluation. So the second evaluation does not evaluate the expression, instead it selects the same position columns than the first evaluation.
In fact, if you add print(name) inside the function severalEvals, instead of returning the typical warning tidyselect expressions can not be evaluated... It returns name = c(1, 3).

library(dplyr, warn.conflicts = FALSE)
#> Warning: package 'dplyr' was built under R version 4.2.3

x <- tibble(a = 1, b = 1, aa = 1) |>
  select(all_of(starts_with("a")))
y <- tibble(b = 1, a = 1, aa = 1) |>
  select(all_of(starts_with("a")))
list(x, y)
#> [[1]]
#> # A tibble: 1 × 2
#>       a    aa
#>   <dbl> <dbl>
#> 1     1     1
#> 
#> [[2]]
#> # A tibble: 1 × 2
#>       a    aa
#>   <dbl> <dbl>
#> 1     1     1

severalEvals <- function(name) {
  x <- tibble(a = 1, b = 1, aa = 1) |>
    select(all_of(name))
  y <- tibble(b = 1, a = 1, aa = 1) |>
    select(all_of(name))
  list(x, y)
}

severalEvals(starts_with("a"))
#> [[1]]
#> # A tibble: 1 × 2
#>       a    aa
#>   <dbl> <dbl>
#> 1     1     1
#> 
#> [[2]]
#> # A tibble: 1 × 2
#>       b    aa
#>   <dbl> <dbl>
#> 1     1     1

^{Created on 2024-03-07 with reprex v2.0.2}

Is this the expected behavior? Is there a way to get the behavior I was expecting?

[catalamarti]

@MimiYuchenGuo have find that we could solve it with {{:

library(dplyr, warn.conflicts = FALSE)
#> Warning: package 'dplyr' was built under R version 4.2.3

severalEvals <- function(name) {
  x <- tibble(a = 1, b = 1, aa = 1) |>
    select({{name}})
  y <- tibble(b = 1, a = 1, aa = 1) |>
    select({{name}})
  list(x, y)
}

severalEvals(starts_with("a"))
#> [[1]]
#> # A tibble: 1 × 2
#>       a    aa
#>   <dbl> <dbl>
#> 1     1     1
#> 
#> [[2]]
#> # A tibble: 1 × 2
#>       a    aa
#>   <dbl> <dbl>
#> 1     1     1

^{Created on 2024-03-07 with reprex v2.0.2}

But it is still an unexpected behavior for me.

[lionel-]

This is expected, tidyselection require {{ for passing arguments.

They sort of work in some cases with lazy evaluation (as in your several-eval example). However once the argument is forced it will not be evaluated again in that case.