[GitHub] [arrow] pitrou commented on a change in pull request #10199: ARROW-12431: [C++] Mask is inverted when creating FixedSizeBinaryArray

[GitBox <gi...@apache.org>]

pitrou commented on a change in pull request #10199:
URL: https://github.com/apache/arrow/pull/10199#discussion_r625052940



##########
File path: cpp/src/arrow/python/numpy_to_arrow.cc
##########
@@ -594,7 +594,13 @@ Status NumPyConverter::Visit(const FixedSizeBinaryType& type) {
 
   if (mask_ != nullptr) {
     Ndarray1DIndexer<uint8_t> mask_values(mask_);
-    RETURN_NOT_OK(builder.AppendValues(data, length_, mask_values.data()));
+    std::unique_ptr<uint8_t[]> inverted_mask(new uint8_t[length_]);
+    for (int64_t i = 0; i < length_; ++i) {
+      inverted_mask[i] = !mask_values[i];
+    }

Review comment:
       This is doing a spurious additional allocation and memory copy. You could reuse `MaskToBitmap` instead.

##########
File path: python/pyarrow/tests/test_array.py
##########
@@ -2666,6 +2666,31 @@ def test_array_masked():
     assert arr.type == pa.int64()
 
 
+def test_binary_array_masked():
+    # ARROW-12431
+    masked_basic = pa.array([b'\x05'], type=pa.binary(1),
+                            mask=np.array([False]))
+    assert [b'\x05'] == masked_basic.to_pylist()
+
+    # Fixed Length Binary
+    masked = pa.array(np.array([b'\x05']), type=pa.binary(1),
+                      mask=np.array([False]))
+    assert [b'\x05'] == masked.to_pylist()
+
+    masked_nulls = pa.array(np.array([b'\x05']), type=pa.binary(1),
+                            mask=np.array([True]))
+    assert [None] == masked_nulls.to_pylist()
+
+    # Variable Length Binary
+    masked = pa.array(np.array([b'\x05']), type=pa.binary(-1),

Review comment:
       This should be `pa.binary()`, not `pa.binary(-1)`.




-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
users@infra.apache.org