[C++] PyBuffer dtor may segfault if constructor passed an object not exporting buffer protocol

[asfimport]

See https://github.com/apache/arrow/blob/master/cpp/src/arrow/python/common.cc#L64

Reporter: Wes McKinney / @wesm
Assignee: Wes McKinney / @wesm

Related issues:

• Arrow 0.3 release (blocks)

_{Note: This issue was originally created as ARROW-726. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
PR: #459

[asfimport]

Wes McKinney / @wesm:
Issue resolved by pull request 459
#459