parse_datetime uses UTC instead of system default when locale(tz="")

[pgramme]

Dear readr ;-)

The documentation of locale(...) says that system default timezone should be used when tz="". But on Windows, with CET as system timezone, this is not what I observe: it seems UTC is used instead.

See the last row in the following reprex: the timezone of the datetime is correctly set to "", but its value shows that it was interpreted as UTC and displayed as CET.

Am I interpreting the doc incorrectly or is it a bug?

Thanks!
Pierre

library(readr)

version
#>                _                           
#> platform       x86_64-w64-mingw32          
#> arch           x86_64                      
#> os             mingw32                     
#> system         x86_64, mingw32             
#> status                                     
#> major          4                           
#> minor          0.2                         
#> year           2020                        
#> month          06                          
#> day            22                          
#> svn rev        78730                       
#> language       R                           
#> version.string R version 4.0.2 (2020-06-22)
#> nickname       Taking Off Again
packageVersion("readr")
#> [1] '1.4.0'

check_tz = function(tz) {
  l = locale(tz = tz)
  tibble::tibble(
    tz0=tz, 
    s0 = "2021-01-01 09:00", 
    dt0 = parse_datetime(s0, locale = l), 
    tz1 = lubridate::tz(dt0),
    s1 = output_column(dt0)
  )
}

Sys.timezone()
#> [1] "Europe/Paris"
check_tz("UTC")
#> # A tibble: 1 x 5
#>   tz0   s0               dt0                 tz1   s1                  
#>   <chr> <chr>            <dttm>              <chr> <chr>               
#> 1 UTC   2021-01-01 09:00 2021-01-01 09:00:00 UTC   2021-01-01T09:00:00Z
check_tz("CET")
#> # A tibble: 1 x 5
#>   tz0   s0               dt0                 tz1   s1                  
#>   <chr> <chr>            <dttm>              <chr> <chr>               
#> 1 CET   2021-01-01 09:00 2021-01-01 09:00:00 CET   2021-01-01T08:00:00Z
check_tz("")
#> # A tibble: 1 x 5
#>   tz0   s0               dt0                 tz1   s1                  
#>   <chr> <chr>            <dttm>              <chr> <chr>               
#> 1 ""    2021-01-01 09:00 2021-01-01 10:00:00 ""    2021-01-01T09:00:00Z

# Problem with the line above: datetime parsed as in UTC and displayed in the system tz

^{Created on 2021-03-26 by the reprex package (v0.3.0)}

[hadley]

This all looks ok to me now:

library(readr)

check_tz <- function(tz) {
  parse_datetime("2021-01-01 09:00", locale = locale(tz = tz))
}

check_tz("UTC")
#> [1] "2021-01-01 09:00:00 UTC"
check_tz("CET")
#> [1] "2021-01-01 09:00:00 CET"

check_tz("")
#> [1] "2021-01-01 09:00:00 CST"
check_tz(Sys.timezone())
#> [1] "2021-01-01 09:00:00 CST"

^{Created on 2023-07-31 with reprex v2.0.2}