R6 detect if a method was overridden

R6_override.R

library(R6)
A <- R6Class(
  "A",
  public = list(
    f = function() {
      cat("Called A$f()\n")
      if (
        is.null(self$.__enclos_env__$super) ||
        identical(self$.__enclos_env__$super$g, self$g)
      ) {
        cat("Method A$g was NOT overridden\n")
      } else {
        cat("Method A$g was overridden\n")
      }
    },
    g = function() {
      cat("Called A$g()")
    }
  )
)


B <- R6Class(
  "B",
  inherit = A,
  public = list(
    g = function() {
      cat("Called B$g()")
    }
  )
)


C <- R6Class(
  "C",
  inherit = A
)

a <- A$new()
a$f()
#> Called A$f()
#> Method A$g was NOT overridden

b <- B$new()
b$f()
#> Called A$f()
#> Method A$g was overridden

c <- C$new()
c$f()
#> Called A$f()
#> Method A$g was NOT overridden