Defer silently swallows errors?

[hadley]

f <- function() {
  on.exit(stop("!"))
}
f()
#> Error in f(): !

f2 <- function() { 
  withr::defer(stop("!")) 
}
f2()

^{Created on 2020-09-01 by the reprex package (v0.3.0.9001)}

[jimhester]

This seems to be by design, defer includes a tryCatch() that explicitly captures errors.

It was originally added to later in kevinushey/later@8ba9ba0.

It is not clear to me if it is really needed however, or just considered useful behavior.

[hadley]

I guess the goal is that an error in one deferred operation shouldn't cause others to fail. But maybe any errors should still be recorded and then replayed?

[gaborcsardi]

I think this makes sense in most cases, but it would be still nice to get the errors or at least the first error somehow. E.g. in (dev) testthat we don't see any teardown errors currently.