ARROW-17088: [R] Use .arrow as extension of IPC files of datasets

r/R/dataset-write.R

@@ -34,8 +34,9 @@
 #' use the current `group_by()` columns.
 #' @param basename_template string template for the names of files to be written.
 #' Must contain `"{i}"`, which will be replaced with an autoincremented
-#' integer to generate basenames of datafiles. For example, `"part-{i}.feather"`
-#' will yield `"part-0.feather", ...`.
+#' integer to generate basenames of datafiles. For example, `"part-{i}.arrow"`
+#' will yield `"part-0.arrow", ...`.
+#' If not specified, it defaults to "part-{i}." + format.
 #' @param hive_style logical: write partition segments as Hive-style
 #' (`key1=value1/key2=value2/file.ext`) or as just bare values. Default is `TRUE`.
 #' @param existing_data_behavior The behavior to use when there is already data
@@ -123,7 +124,7 @@ write_dataset <- function(dataset,
                           path,
                           format = c("parquet", "feather", "arrow", "ipc", "csv"),
                           partitioning = dplyr::group_vars(dataset),
-                          basename_template = paste0("part-{i}.", as.character(format)),
+                          basename_template = NULL,
                           hive_style = TRUE,
                           existing_data_behavior = c("overwrite", "error", "delete_matching"),
                           max_partitions = 1024L,
@@ -170,6 +171,11 @@ write_dataset <- function(dataset,
     }
   }
 
+  if (is.null(basename_template)) {
+    format <- ifelse(as.character(format) %in% c("feather", "ipc"), "arrow", format)
+    basename_template <- paste0("part-{i}.", as.character(format))
+  }
+
   path_and_fs <- get_path_and_filesystem(path)
   output_schema <- final_node$schema
   options <- FileWriteOptions$create(

r/tests/testthat/test-dataset-write.R

@@ -63,7 +63,7 @@ test_that("Writing a dataset: CSV->IPC", {
 
   # Check whether "int" is present in the files or just in the dirs
   first <- read_feather(
-    dir(dst_dir, pattern = ".feather$", recursive = TRUE, full.names = TRUE)[1],
+    dir(dst_dir, pattern = ".arrow$", recursive = TRUE, full.names = TRUE)[1],
     as_data_frame = FALSE
   )
   # It shouldn't be there
@@ -139,6 +139,23 @@ test_that("Writing a dataset: Parquet->Parquet (default)", {
   )
 })
 
+test_that("Writing a dataset: `basename_template` default behavier", {
+  ds <- open_dataset(csv_dir, partitioning = "part", format = "csv")
+
+  feather_dir <- make_temp_dir()
+  write_dataset(ds, feather_dir, format = "feather", partitioning = "int")
+  expect_identical(
+    dir(feather_dir, full.names = FALSE, recursive = TRUE),
+    sort(paste(paste("int", c(1:10, 101:110), sep = "="), "part-0.arrow", sep = "/"))
+  )
+  ipc_dir <- make_temp_dir()
+  write_dataset(ds, ipc_dir, format = "ipc", partitioning = "int")
+  expect_identical(
+    dir(ipc_dir, full.names = FALSE, recursive = TRUE),
+    sort(paste(paste("int", c(1:10, 101:110), sep = "="), "part-0.arrow", sep = "/"))
+  )
+})
+
 test_that("Writing a dataset: existing data behavior", {
   # This test does not work on Windows because unlink does not immediately
   # delete the data.
@@ -458,8 +475,10 @@ test_that("Writing a dataset: CSV format options", {
 test_that("Dataset writing: unsupported features/input validation", {
   skip_if_not_available("parquet")
   expect_error(write_dataset(4), "You must supply a")
-  expect_error(write_dataset(data.frame(x = 1, x = 2, check.names = FALSE)),
-               "Field names must be unique")
+  expect_error(
+    write_dataset(data.frame(x = 1, x = 2, check.names = FALSE)),
+    "Field names must be unique"
+  )
 
   ds <- open_dataset(hive_dir)
   expect_error(
@@ -469,9 +488,6 @@ test_that("Dataset writing: unsupported features/input validation", {
   expect_error(
     write_dataset(ds, tempfile(), basename_template = "something_without_i")
   )
-  expect_error(
-    write_dataset(ds, tempfile(), basename_template = NULL)
-  )
 })
 
 # see https://issues.apache.org/jira/browse/ARROW-12315