NSE Arguments in functions calling plotly raise an error

While toying with different NSE approaches I stumbled upon the following behaviour which seems to me like a bug. Any NSE argument (even if not used in plotly) results in an error:

library(plotly)

nse_arg_raises_error <- function(xx) {
   mf <- rlang::new_formula(NULL, rlang::ensym(xx), globalenv())
   plot_ly(mtcars, x = ~ cyl, y = ~ mpg, type = "scatter",
           mode = "markers")
}
nse_arg_raises_error()    ## works
nse_arg_raises_error(cyl) ## does not work
#> Error in as.list.environment(x, all.names = TRUE): object 'cyl' not found

This behaviour is unique to plotly, b/c if I leave out the plot_ly call, the error does not happen.

it_is_a_plotly_problem <- function(xx) {
   mf <- rlang::new_formula(NULL, rlang::ensym(xx), globalenv())
   1 + 1
}
it_is_a_plotly_problem()     ## works
#> [1] 2
it_is_a_plotly_problem(cyl)  ## also works
#> [1] 2

However, some preliminary debugging shows that the culprit sits (deep) in base:::as.list.environment (which is called from lazyeval:::clone_env, which in turn together with its brethren from lazyeval is responsible for the NSE part in plot_ly)

it_is_a_as_list_environment_issue <- function(xx) {
   mf <- rlang::new_formula(NULL, rlang::ensym(xx), globalenv())
   cp <- as.list.environment(environment())
   1 + 1
}
it_is_a_as_list_environment_issue(cyl)
#> Error in as.list.environment(x, all.names = TRUE): object 'cyl' not found

So basically, when lazyeval:::clone_env copies the function environment which contains an NSE argument this error from within the C code implementation of base::as.list.environment bubbles up.

I am inclined to say that this a feature and not a bug of as.list.environment and the user of it should make sure that environments using it are in fact able to be safely transformed into a list. Thus, I am posting the issue here as it touches the whole NSE strategy of plotly - coming from plotly:::eval_attr (especially since lazyeval is retired in favor of rlang).

提供された nse_arg_raises_error の例で問題を再現し、次に plotly:::eval_attr から lazyeval:::clone_env、さらに base:::as.list.environment の呼び出しまで追跡します。未使用の NSE 引数を含む関数環境を plotly の NSE パスがどのように処理するかを確認します。示されている plot_ly 呼び出しで as.list.environment エラーが発生しなくなれば完了です。payload にはテストファイルの指定はありません。