dragosmg opened a new issue, #49836:
URL: https://github.com/apache/arrow/issues/49836
### Describe the bug, including details regarding any error messages,
version, and platform.
I am not 100% convinced this is a bug or rather some unexpected behaviour.
When an R `Date` vector contains `Inf` or `-Inf`, converting to an Arrow
table (e.g. via `as_arrow_table()` or `write_parquet()`) silently converts
these to extreme, but finite, dates instead of `null` or raising an error.
**Reprex**:
``` r
library(arrow)
library(tibble)
library(dplyr)
tibble(x = as.Date(c(Inf, -Inf))) |>
as_arrow_table() |>
collect()
#> # A tibble: 2 × 1
#> x
#> <date>
#> 1 5881580-07-11
#> 2 -5877641-06-23
```
Second example (includes `NaN`):
``` r
library(arrow)
library(tibble)
library(dplyr)
chunks <- tibble(x = as.Date(c(Inf, -Inf, NaN))) |>
as_arrow_table()
chunks$columns
#> [[1]]
#> ChunkedArray
#> <date32[day]>
#> [
#> [
#> <value out of range: 2147483647>,
#> <value out of range: -2147483648>,
#> 1970-01-01
#> ]
#> ]
```
A final reprex to highlight the problematic aspect of casting to `int32`
which results in `NA_integer_` clashing with `INT_MIN`:
``` r
library(arrow)
library(tibble)
library(dplyr)
tibble(x = as.Date(c(Inf, -Inf, NaN))) |>
as_arrow_table() |>
collect() |>
mutate(y = as.integer(x))
#> Warning: There was 1 warning in `mutate()`.
#> ℹ In argument: `y = as.integer(x)`.
#> Caused by warning:
#> ! NAs introduced by coercion to integer range
#> # A tibble: 3 × 2
#> x y
#> <date> <int>
#> 1 5881580-07-11 2147483647
#> 2 -5877641-06-23 NA
#> 3 1970-01-01 0
```
**Expected behaviour**:
I think it might be better if `Inf`/`-Inf` dates are either converted to
`null` in the Arrow array, or the conversion should error/warn indicating that
infinite date values are not representable in `date32`.
**Root cause**:
In https://github.com/apache/arrow/blob/main/r/src/r_to_arrow.cpp#L600,
`FromRdate` for `Date32Type` does:
```
static int FromRDate(const Date32Type*, double from) {
return static_cast<int>(std::floor(from));
}
```
As far as I understand, `static_cast<int>(std::floor(Inf))` is undefined
behaviour in C++. On most platforms this would produce `INT_MAX`/ `INT_MIN`,
which Arrow then interprets as concrete dates ~5.8 million years from epoch.
A possible fix would be to check for non-finite values before the cast:
```
static int FromRDate(const Date32Type*, double from) {
if (!std::infinite(from)) {
// handle as null or error/ warn
}
return static_cast<int>(std::floor(from));
}
```
`NaN` date are also affected by the same behaviour. Arguably more
problematic as the roundtrip transforms them into `0` (i.e. epoch).
### Component(s)
R
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