[C++] Array Take may dereference absent null bitmap

[asfimport]

Sorting a non-chunked array has some sort of reference problem. Some operations on the resulting indices array crash.

import pyarrow as pa, pyarrow.compute as pc

array = pa.array(list("abcba"))
assert pc.sort_indices(pa.chunked_array([array])).take([0])
assert pc.array_sort_indices(pa.chunked_array([array])).take([0])
pc.sort_indices(array).take([0])  # crash
pc.array_sort_indices(array).take([0])  # crash

Environment: macOS, ubuntu
Reporter: A. Coady / @coady
Assignee: Antoine Pitrou / @pitrou

PRs and other links:

• GitHub Pull Request #9546

_{Note: This issue was originally created as ARROW-11694. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
Quick drive-by patch:

diff --git a/cpp/src/arrow/compute/kernels/util_internal.cc b/cpp/src/arrow/compute/kernels/util_internal.cc
index 93badbd3b..1656ed2aa 100644
--- a/cpp/src/arrow/compute/kernels/util_internal.cc
+++ b/cpp/src/arrow/compute/kernels/util_internal.cc
@@ -53,7 +53,7 @@ PrimitiveArg GetPrimitiveArg(const ArrayData& arr) {
     arg.data += arr.offset * arg.bit_width / 8;
   }
   // This may be kUnknownNullCount
-  arg.null_count = arr.null_count.load();
+  arg.null_count = (arg.is_valid != nullptr) ? arr.null_count.load() : 0;
   return arg;
 }
 

[asfimport]

Ben Kietzman / @bkietz:
Issue resolved by pull request 9546
#9546