[ARROW-1402] [C++] Possibly deprecate public APIs that use MutableBuffer

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.7.0
• Component/s: C++
• External issue URL: https://github.com/apache/arrow/issues/17428
• Assignee: Wes McKinney
• Reporter: Wes McKinney
• Created: 23/Aug/17 02:42
• Updated: 11/Jan/23 07:14
• Resolved: 29/Aug/17 08:27

Description

I am not sure it is useful to expose arrow::MutableBuffer as the out argument in functions like arrow::AllocateBuffer. See e.g. http://arrow.apache.org/docs/cpp/namespacearrow.html#a4e4daf985e41d6879c9dbb0131157c51

In my experience this is more of a nuisance than anything, as mutability is a dynamic property of buffers (we have buffer->is_mutable() on base instances). If we were doing a lot of compile time reasoning about buffers, that would be a different story, but we are not.

I don't think we should nix the MutableBuffer class, just return pointers to base from functions. We can still get it back with std::dynamic_pointer_cast.