[ARROW-14297] [R] smooth out integer division to better match R

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 7.0.0
• Component/s: R
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/29871
• Assignee: Dewey Dunnington
• Reporter: Dragoș Moldovan-Grünfeld
• Created: 12/Oct/21 14:58
• Updated: 11/Jan/23 08:39
• Resolved: 17/Nov/21 14:34

Description

Behaviour of integer division from Arrow differs from R. 

> a <- c(1:4, NA_integer_)
> a_arrow <- Array$create(a)
> 
> expect_identical(as.vector(a_arrow %/% 2), a %/% 2)
Error: as.vector(a_arrow%/%2) (`actual`) not identical to a%/%2 (`expected`).

`actual` is an integer vector (0, 1, 1, 2, NA)
`expected` is a double vector (0, 1, 1, 2, NA)
> 
> # this actually works, but on accident as in R the type of the denominator
> # is the one that determines the type of the output 
> expect_identical(as.vector(a_arrow %/% 2L), a %/% 2L)
> 
> expect_identical(as.vector(a_arrow %/% 0), a %/% 0)
Error: as.vector(a_arrow%/%0) (`actual`) not identical to a%/%0 (`expected`).

`actual` is an integer vector (2147483647, 2147483647, 2147483647, 2147483647, NA)
`expected` is a double vector (Inf, Inf, Inf, Inf, NA)
> expect_identical(as.vector(a_arrow %/% 0L), a %/% 0L)
Error: as.vector(a_arrow%/%0L) (`actual`) not identical to a%/%0L (`expected`).

  `actual`: 2147483647 2147483647 2147483647 2147483647 NA
`expected`:         NA         NA         NA         NA NA
> 
> b <- -a
> b_arrow <- Array$create(b)
> expect_identical(as.vector(b_arrow %/% 2), b %/% 2)
Error: as.vector(b_arrow%/%2) (`actual`) not identical to b%/%2 (`expected`).

`actual` is an integer vector (0, -1, -1, -2, NA)
`expected` is a double vector (-1, -1, -2, -2, NA)
> expect_identical(as.vector(b_arrow %/% .2), b %/% .2)
Error: as.vector(b_arrow%/%0.2) (`actual`) not identical to b%/%0.2 (`expected`).

`actual` is an integer vector (-5, -10, -15, -20, NA)
`expected` is a double vector (-5, -10, -15, -20, NA)

expect_dplyr_equal() uses expect_equal() which does not enforce type.

This is a follow-up issue to ARROW-13800 

Issue Links

• links to: GitHub Pull Request #11652