[C++] NumericArray<T> may not initialize values_ when construct

[mapleFU]

Describe the bug, including details regarding any error messages, version, and platform.

The problem raised from [1]. NumericArray<T> uses values_ as a cache of typed values[2]. This might not being set when calling the PrimitiveArray::PrimitiveArray constructor [3]. The code can be reproduced like:

TEST(TestPrettyPrintArray, TimestampArray) {
  auto array = std::make_shared<TimestampArray>(
      timestamp(TimeUnit::MICRO),
      /*length=*/1, Buffer::FromVector(std::vector<int64_t>{0}));
  auto v0 = array->GetView(0);
  std::cout << v0 << std::endl;
}

This might be fixed with:

diff --git a/cpp/src/arrow/array/array_primitive.h b/cpp/src/arrow/array/array_primitive.h
index 3e2893b7dd..410e8516da 100644
--- a/cpp/src/arrow/array/array_primitive.h
+++ b/cpp/src/arrow/array/array_primitive.h
@@ -103,6 +103,15 @@ class NumericArray : public PrimitiveArray {
                             null_count, offset));
   }
 
+  NumericArray(const std::shared_ptr<DataType>& type, int64_t length,
+                 const std::shared_ptr<Buffer>& data,
+                 const std::shared_ptr<Buffer>& null_bitmap = NULLPTR,
+                 int64_t null_count = kUnknownNullCount, int64_t offset = 0): PrimitiveArray(type, length, data, null_bitmap, null_count, offset) {
+      values_ = raw_values_
+                    ? (reinterpret_cast<const value_type*>(raw_values_) + data_->offset)
+                    : NULLPTR;
+  }
+
   const value_type* raw_values() const { return values_; }
 
   value_type Value(int64_t i) const { return values_[i]; }

But I don't know would I missed something.

[1] #44190
[2]

arrow/cpp/src/arrow/array/array_primitive.h

Line 131 in a3c39ec

const value_type* values_;

[3]

arrow/cpp/src/arrow/array/array_primitive.h

Line 122 in a3c39ec

using PrimitiveArray::PrimitiveArray;

Component(s)

C++

[mapleFU]

Issue resolved by pull request 44542
#44542