ARROW-17543: [R] Fix bug for NULL type 0-length vectors in array crea…

…tion Added the suggested check in ```Array$create()``` from the JIRA issue, that if both the ```x``` and ```type``` are ```NULL``` then the type is manually assigned to ```arrow::null()```. Added unit tests that captured the bug before I applied the fix and now pass. Closes #13990 from egillax/detect_and_fix_type_null_vectors Authored-by: Egill Fridgeirsson <[email protected]> Signed-off-by: Nic Crane <[email protected]>
apache · Aug 31, 2022 · cf27001 · cf27001
1 parent 854283d
commit cf27001
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diff --git a/r/R/array.R b/r/R/array.R
@@ -176,6 +176,9 @@ Array$create <- function(x, type = NULL) {
   if (!is.null(type)) {
     type <- as_type(type)
   }
+  if (is.null(x) && is.null(type)) {
+    type <- null()
+  }
   if (inherits(x, "Scalar")) {
     out <- x$as_array()
     if (!is.null(type)) {

diff --git a/r/tests/testthat/test-Array.R b/r/tests/testthat/test-Array.R
@@ -180,6 +180,11 @@ test_that("Array support null type (ARROW-7064)", {
   expect_array_roundtrip(vctrs::unspecified(10), null())
 })
 
+test_that("Array support 0-length NULL vectors (Arrow-17543)", {
+  expect_type_equal(Array$create(c()), null())
+  expect_type_equal(Array$create(NULL), null())
+})
+
 test_that("Array supports logical vectors (ARROW-3341)", {
   # with NA
   x <- sample(c(TRUE, FALSE, NA), 1000, replace = TRUE)