Printing stack trace and continuing after error occurs in R

Question

I\'m writing some R code that calls other code that may fail. If it does, I want to print a stack trace (to track down what went wrong), then carry on regardless. However, t

Answer 1

If something that triggers on option(error...) is of interest, you can also do this:

options(error=traceback)

From what I can tell, it does most of what Bob's suggested solution do, but has the advantage of being much shorter.

(Feel free to combine with keep.source=TRUE, warn=2, etc. as needed.)

Answer 2

I wrote a solution that works like try, except that it also returns the call stack.

tryStack <- function(
expr,
silent=FALSE
)
{
tryenv <- new.env()
out <- try(withCallingHandlers(expr, error=function(e)
  {
  stack <- sys.calls()
  stack <- stack[-(2:7)]
  stack <- head(stack, -2)
  stack <- sapply(stack, deparse)
  if(!silent && isTRUE(getOption("show.error.messages"))) 
    cat("This is the error stack: ", stack, sep="\n")
  assign("stackmsg", value=paste(stack,collapse="\n"), envir=tryenv)
  }), silent=silent)
if(inherits(out, "try-error")) out[2] <- tryenv$stackmsg
out
}

lower <- function(a) a+10
upper <- function(b) {plot(b, main=b) ; lower(b) }

d <- tryStack(upper(4))
d <- tryStack(upper("4"))
cat(d[2])

More info in my answer here: https://stackoverflow.com/a/40899766/1587132