R Error - cannot change value of locked binding for 'df'

Question

I\'m trying to filter some data, with functions in R relatives to data frames. But in the second function, it gives me the following error: cannot change the value of locked bin

Answer 1

I had this problem when creating function inside a package, and I was using <<- inside exported function to overwrite some functions from different package. I've created hack with env <- parent.env() and adding this to parent env instead since the function was always called at top level. So env will be scope of the code that call the function not the package.

here is complete code of this function, it overwrite shiny and current package functions:

#' @export
useMocks <- function() {
  observeEvent <- battery::observeEventMock
  assignInNamespace("observeEvent", observeEvent, "battery")
  assignInNamespace("observeEvent", observeEvent, "shiny")
  isolate <- battery::isolate
  assignInNamespace("isolate", isolate, "shiny")
  makeReactiveBinding <- battery::makeReactiveBinding
  assignInNamespace("makeReactiveBinding", makeReactiveBinding, "shiny")
  renderUI <- battery::renderUI
  assignInNamespace("renderUI", renderUI, "shiny")
  ## we modify the parent frame so it update environment when function is called not the package
  env <- parent.frame()
  env$observeEvent <- observeEvent
  env$isolate <- isolate
  env$renderUI <- renderUI

}

using <<- throw this error here because you can't modify the package scope.

observeEvent <<- battery::observeEventMock

this don't work