Error when used with memoise

[rorynolan]

I can't really tell what's going on here, but I'm getting an error about setdiff() when I haven't used it at all.

library(conflicted)
library(tidyverse)
library(lubridate)
library(memoise)

tib <- tibble(x = 1:2, y = 3:4)

f <- function(tib) {
  mutate(tib, z = if_else(x == 1, y, x))
}
mf <- memoise(f)

f(tib)
#> # A tibble: 2 x 3
#>       x     y     z
#>   <int> <int> <int>
#> 1     1     3     3
#> 2     2     4     2

mf(tib)
#> [conflicted] `setdiff` found in 2 packages.
#> Either pick the one you want with `::` 
#> * lubridate::setdiff
#> * dplyr::setdiff
#> Or declare a preference with `conflict_prefer()`
#> * conflict_prefer("setdiff", "lubridate")
#> * conflict_prefer("setdiff", "dplyr")

^{Created on 2019-07-23 by the reprex package (v0.3.0)}

[GegznaV]

I also faced a similar issue, when I had to resolve a conflict related to setdiff(), when I did not use it. But I think @rorynolan's example is reproducible enough.

Furthermore, this issue seems to be related: #44

[moodymudskipper]

You are using setdiff because it's part of the body of mf (check body(mf)) and mf is not namespaced so the use of setdiff is indeed ambiguous.

It might be a memoise issue, and maybe we should use the :: notation everywhere in manufactured functions as a good practice ? This won't help with overloaded operators though.

We can fix this specific case by substituting setdiff with base::setdiff in the manufacture function's body.

library(conflicted)
library(tidyverse)
library(lubridate)
library(memoise)

tib <- tibble(x = 1:2, y = 3:4)

f <- function(tib) {
  mutate(tib, z = if_else(x == 1, y, x))
}
mf <- memoise(f)
body(mf) <- do.call(substitute, list(body(mf), list(setdiff = quote(base::setdiff))))
class(mf) <- c("memoised", "function") # seems that `body<-` strips off the class :(

f(tib)
#> # A tibble: 2 x 3
#>       x     y     z
#>   <int> <int> <int>
#> 1     1     3     3
#> 2     2     4     2

mf(tib)
#> # A tibble: 2 x 3
#>       x     y     z
#>   <int> <int> <int>
#> 1     1     3     3
#> 2     2     4     2

^{Created on 2019-11-21 by the reprex package (v0.3.0)}

[hadley]

This is now resolved because lubridate and dplyr use the same definition of setdiff(), but I think this is the correct behaviour and reveals a real issue in memoise.