naive_time_parse() can fail when rounding up to 60 seconds

[DavisVaughan]

library(clock)

# Round up to 60 seconds (looks invalid)? That causes the NA?
naive_time_parse("2021-04-16T22:35:59.955Z", format = "%Y-%m-%dT%H:%M:%6SZ", precision = "second")

# Rounds up to a valid 59 seconds
naive_time_parse("2021-04-16T22:35:58.955Z", format = "%Y-%m-%dT%H:%M:%6SZ", precision = "second")

# No rounding
naive_time_parse("2021-04-16T22:35:59.955Z", format = "%Y-%m-%dT%H:%M:%6SZ", precision = "millisecond")

[DavisVaughan]

HowardHinnant/date#667

[DavisVaughan]

Possibly solve by instead parsing into microseconds, and then giving the user the option of how to round. Advise them to use a real clock type if they have more precise date-times than microsecond that they need to parse, or if they want to keep the fractional seconds.

Consider how this should work for other date-time parsers, and for the date parser.

library(clock)
library(rlang)

date_time_parse <- function(x,
                            zone,
                            ...,
                            format = NULL,
                            locale = clock_locale(),
                            fractional = "floor",
                            nonexistent = NULL,
                            ambiguous = NULL) {
  x <- naive_time_parse(x, ..., format = format, precision = "microsecond", locale = locale)
  rounder <- get_rounder(fractional)
  x <- rounder(x, "second")
  as.POSIXct(x, tz = zone, nonexistent = nonexistent, ambiguous = ambiguous)
}

get_rounder <- function(fractional) {
  fractional <- arg_match0(fractional, c("cast", "round", "floor", "ceiling"), "fractional")
  
  switch (
    fractional,
    cast = time_point_cast,
    round = time_point_round,
    floor = time_point_floor,
    ceiling = time_point_ceiling
  )
}

drive_modified_time <- c(
  "2021-04-16T22:36:30.686Z",
  "2021-04-16T22:35:59.955Z",
  "2021-04-16T22:35:34.369Z"
)

# this continues to work
date_time_parse(drive_modified_time, zone = "UTC", format = "%Y-%m-%dT%H:%M:%6SZ")
#> [1] "2021-04-16 22:36:30 UTC" "2021-04-16 22:35:59 UTC"
#> [3] "2021-04-16 22:35:34 UTC"

# this now works
date_time_parse(drive_modified_time, zone = "UTC", format = "%Y-%m-%dT%H:%M:%SZ")
#> [1] "2021-04-16 22:36:30 UTC" "2021-04-16 22:35:59 UTC"
#> [3] "2021-04-16 22:35:34 UTC"

# can control rounding method
date_time_parse(drive_modified_time, zone = "UTC", format = "%Y-%m-%dT%H:%M:%SZ", fractional = "round")
#> [1] "2021-04-16 22:36:31 UTC" "2021-04-16 22:36:00 UTC"
#> [3] "2021-04-16 22:35:34 UTC"

# this is unsupported
date_time_parse(
  "2021-04-16T22:36:30.1234567Z",
  zone = "UTC", 
  format = "%Y-%m-%dT%H:%M:%SZ"
)
#> Warning: Failed to parse 1 string at location 1. Returning `NA` at that
#> location.
#> [1] NA

# technically can do this, but leave undocumented
date_time_parse(
  "2021-04-16T22:36:30.1234567Z",
  zone = "UTC", 
  format = "%Y-%m-%dT%H:%M:%10SZ"
)
#> [1] "2021-04-16 22:36:30 UTC"

^{Created on 2021-05-07 by the reprex package (v1.0.0)}