atharva-potdar opened a new issue, #55445:
URL: https://github.com/apache/arrow/issues/55445
### Describe the bug, including details regarding any error messages,
version, and platform.
Currently, the slicing constructors for `Buffer` (`cpp/src/arrow/buffer.h`)
and `MutableBuffer` (`cpp/src/arrow/buffer.cc`) unconditionally add `offset` to
the parent buffer's pointer/address:
```cpp
// cpp/src/arrow/buffer.h
Buffer(std::shared_ptr<Buffer> parent, const int64_t offset, const int64_t
size)
: Buffer(parent->data_ + offset, size) { ... }
// cpp/src/arrow/buffer.cc
MutableBuffer::MutableBuffer(const std::shared_ptr<Buffer>& parent, const
int64_t offset,
const int64_t size)
: MutableBuffer(reinterpret_cast<uint8_t*>(parent->mutable_address()) +
offset,
size) { ... }
```
When slicing a null-backed buffer where `parent->data_` is `nullptr` or
`parent->mutable_address()` is `0` with a non-zero `offset` (e.g.,
`SliceBuffer(std::make_shared<Buffer>(nullptr, 16), 8, 8)`):
1. It performs undefined pointer arithmetic on a null pointer
(`[expr.add]`), producing a non-null corrupted address (`0x8` instead of
`nullptr`).
2. It triggers `clang-analyzer-core.NullPointerArithm` in `clang-tidy`:
```text
cpp/src/arrow/buffer.cc:167:75: warning: Addition of a null pointer and a
nonzero integer value (from variable 'offset') results in undefined behavior
[clang-analyzer-core.NullPointerArithm]
```
### Component(s)
C++
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