ARROW-16415: [R] Update strptime binding signature with the tz argument

r/R/dplyr-funcs-datetime.R

@@ -28,25 +28,57 @@ register_bindings_datetime <- function() {
 }
 
 register_bindings_datetime_utility <- function() {
- register_binding("strptime", function(x, format = "%Y-%m-%d %H:%M:%S", tz = NULL,
+ register_binding("strptime", function(x,
+ format = "%Y-%m-%d %H:%M:%S",
+ tz = "",
  unit = "ms") {
  # Arrow uses unit for time parsing, strptime() does not.
  # Arrow has no default option for strptime (format, unit),
  # we suggest following format = "%Y-%m-%d %H:%M:%S", unit = MILLI/1L/"ms",
  # (ARROW-12809)
 
- # ParseTimestampStrptime currently ignores the timezone information (ARROW-12820).
- # Stop if tz is provided.
- if (is.character(tz)) {
- arrow_not_supported("Time zone argument")
- }
+ unit <- make_valid_time_unit(
+ unit,
+ c(valid_time64_units, valid_time32_units)
+ )
+
+ output <- build_expr(
+ "strptime",
+ x,
+ options =
+ list(
+ format = format,
+ unit = unit,
+ error_is_null = TRUE
+ )
+ )
 
- unit <- make_valid_time_unit(unit, c(valid_time64_units, valid_time32_units))
+ if (tz == "") {
+ tz <- Sys.timezone()
+ }
 
- build_expr("strptime", x, options = list(format = format, unit = unit, error_is_null = TRUE))
+ # if a timestamp does not contain timezone information (i.e. it is
+ # "timezone-naive") we can attach timezone information (i.e. convert it into
+ # a "timezone-aware" timestamp) with `assume_timezone`
+ # if we want to cast to a different timezone, we can only do it for
+ # timezone-aware timestamps, not for timezone-naive ones
+ if (!is.null(tz)) {
+ output <- build_expr(
+ "assume_timezone",
+ output,
+ options =
+ list(
+ timezone = tz
+ )
+ )
+ }
+ output
  })
 
- register_binding("strftime", function(x, format = "", tz = "", usetz = FALSE) {
+ register_binding("strftime", function(x,
+ format = "",
+ tz = "",
+ usetz = FALSE) {
  if (usetz) {
  format <- paste(format, "%Z")
  }

r/tests/testthat/test-dplyr-funcs-datetime.R

@@ -49,50 +49,82 @@ test_df <- tibble::tibble(
 
 test_that("strptime", {
  t_string <- tibble(x = c("2018-10-07 19:04:05", NA))
- t_stamp <- tibble(x = c(lubridate::ymd_hms("2018-10-07 19:04:05"), NA))
+ # lubridate defaults to "UTC" as timezone => t_stamp is in "UTC"
+ t_stamp_with_utc_tz <- tibble(x = c(lubridate::ymd_hms("2018-10-07 19:04:05"), NA))
+ t_stamp_with_pm_tz <- tibble(
+ x = c(lubridate::ymd_hms("2018-10-07 19:04:05", tz = "Pacific/Marquesas"), NA)
+ )
+
+ # base::strptime returns a POSIXlt (a list) => we cannot use compare_dplyr_binding
+ # => we use expect_equal for the tests below
+
+ withr::with_timezone("Pacific/Marquesas", {
+ # the default value for strptime's `tz` argument is "", which is interpreted
+ # as the current timezone. we test here if the strptime binding picks up
+ # correctly the current timezone (similarly to the base R version)
+ expect_equal(
+ t_string %>%
+ record_batch() %>%
+ mutate(
+ x = strptime(x, format = "%Y-%m-%d %H:%M:%S")
+ ) %>%
+ collect(),
+ t_stamp_with_pm_tz
+ )
+ })
+
+ # adding a timezone to a timezone-naive timestamp works
+ # and since our TZ when running the test is (typically) Pacific/Marquesas
+ # this also tests that assigning a TZ different from the current session one
+ # works as expected
+ expect_equal(
+ t_string %>%
+ arrow_table() %>%
+ mutate(
+ x = strptime(x, format = "%Y-%m-%d %H:%M:%S", tz = "Pacific/Marquesas")
+ ) %>%
+ collect(),
+ t_stamp_with_pm_tz
+ )
 
  expect_equal(
  t_string %>%
  Table$create() %>%
  mutate(
- x = strptime(x)
+ x = strptime(x, tz = "UTC")
  ) %>%
  collect(),
- t_stamp,
- ignore_attr = "tzone"
+ t_stamp_with_utc_tz
  )
 
  expect_equal(
  t_string %>%
  Table$create() %>%
  mutate(
- x = strptime(x, format = "%Y-%m-%d %H:%M:%S")
+ x = strptime(x, format = "%Y-%m-%d %H:%M:%S", tz = "UTC")
  ) %>%
  collect(),
- t_stamp,
- ignore_attr = "tzone"
+ t_stamp_with_utc_tz
  )
 
  expect_equal(
  t_string %>%
  Table$create() %>%
  mutate(
- x = strptime(x, format = "%Y-%m-%d %H:%M:%S", unit = "ns")
+ x = strptime(x, format = "%Y-%m-%d %H:%M:%S", unit = "ns", tz = "UTC")
  ) %>%
  collect(),
- t_stamp,
- ignore_attr = "tzone"
+ t_stamp_with_utc_tz
  )
 
  expect_equal(
  t_string %>%
  Table$create() %>%
  mutate(
- x = strptime(x, format = "%Y-%m-%d %H:%M:%S", unit = "s")
+ x = strptime(x, format = "%Y-%m-%d %H:%M:%S", unit = "s", tz = "UTC")
  ) %>%
  collect(),
- t_stamp,
- ignore_attr = "tzone"
+ t_stamp_with_utc_tz
  )
 
  tstring <- tibble(x = c("08-05-2008", NA))
@@ -111,15 +143,6 @@ test_that("strptime", {
  )
 })
 
-test_that("errors in strptime", {
- # Error when tz is passed
- x <- Expression$field_ref("x")
- expect_error(
- call_binding("strptime", x, tz = "PDT"),
- "Time zone argument not supported in Arrow"
- )
-})
-
 test_that("strptime returns NA when format doesn't match the data", {
  df <- tibble(
  str_date = c("2022-02-07", "2012/02-07", "1975/01-02", "1981/01-07", NA)