error handler fails silently in some cases

[flying-sheep]

the following code prints a empty list() although the list should contain the recursion error:

err <- list()
eh <- function(e) err <<- c(err, list(toString(e)))
oh <- evaluate::new_output_handler(error = eh)
evaluate::evaluate(
    'f<-function(x) f(x); f(0)',
    output_handler = oh,
    envir = .GlobalEnv,
    stop_on_error = 1L)
print(err)

if we however do eh <- function(e) err <<- c(err, list(e)), it’ll work. why?

[flying-sheep]

since @yihui said he has no idea, i thought about it some more…

maybe toString does something depending on the global stack trace info and somehow fails in the error function? maybe it can be debugged by writing stuff to a file (since the stdout/err capturing of evaluate interferes otherwise)

[flying-sheep]

hmm…

eh <- function(e) {
    p <- pipe('cat', 'w')
    write('this works', p)
    tryCatch(
        toString(e),
        error = function(err) write('this doesn’t', p),
        finally = write('this neither', p))
    write('this isn’t reached', p)
    close(p)
    err <<- c(err, list(toString(e)))
}

[hadley]

When I run this now, I get:

Error : C stack usage  7954168 is too close to the limit

Likely related to #103