test() won't work after check() when S4 methods are involved

[garrettgman]

...and vice versa

For example, after running

check("lubridate")

test produces the following error

test("lubridate")
Loading lubridate
Error: package slot missing from signature for generic ‘[<-’
  and classes Interval, ANY
  cannot use with duplicate class names (the package may need to be re-installed)

It seems test is trying to reload the S4 methods of lubridate, but gets confused because the methods are already loaded from check(). As a result, test isn't sure how to differentiate the methods it wants to load. The same thing happens when I run check() after test().

The error comes from R's behavior: The same thing happens outside of devtools if I try redefining existing S4 methods. I can use removeMethod("[<-,Interval,ANY") to postpone the error message until R encounters the next pre-existing S4 method - but I really need to remove all at once.

Can check() and test() remove S4 methods on exit?

Garrett

[garrettgman]

Here's more information. The problem disappears when I use check("lubridate", document = F). Also these combinations of code work:

test("lubridate")
test("lubridate")

document("lubridate", clean = TRUE)
document("lubridate", clean = TRUE)

and these do not. They give the error above

test("lubridate")
document("lubridate", clean = TRUE)

document("lubridate", clean = TRUE)
test("lubridate")

[hadley]

Even more minimally:

load_all("lubridate")
document("lubridate")

which is presumably happening because we get two sets of classes defined in two different environments.

[hadley]

Probably the best solution to this is to run in a separate R instance, and some how manually capture the caches and save to disk.

[hadley]

Another approach

library(parallel)
safe_expr <- function(expr) mccollect(mcparallel(expr))[[1]]

safe_expr(a <- 1:10)
safe_expr(library(ggplot2))
a
qplot

[wch]

Fixed in #126.