R/catchWarning.r

In pbreheny/breheny: Miscellaneous Functions

#' Catch warnings
#'
#' This is mainly used for code that either (a) generates a bunch of warnings, which makes it hard
#' to find a warning that may have happened 78 warnings ago, or (b) generates a warning and an error,
#' but it's hard to get at the warning because the error causes the code to crash before the warning
#' is signalled.
#'
#' @param expr   An R expression
#'
#' @examples
#' out <- catchWarning(log('a'))
#' out$value
#' out <- catchWarning(as.numeric(c('1', 'a')))
#' out
#' out <- catchWarning(1+1)
#' out
#' @export

catchWarning <- function(expr) {
  W <- NULL
  w.handler <- function(w){ # warning handler
    W <<- w
    invokeRestart("muffleWarning")
  }
  list(value = withCallingHandlers(tryCatch(expr, error = function(e) e), warning = w.handler),
       warning = W)
}