[C++] Investigate spurious memset() calls

[asfimport]

builder.cc has TODO statements of the form:

  // TODO(emkornfield) valgrind complains without this
  memset(data_->mutable_data(), 0, static_cast<size_t>(nbytes));

Ideally we shouldn't have to zero-initialize a data buffer before writing to it.

Reporter: Antoine Pitrou / @pitrou
Assignee: Antoine Pitrou / @pitrou

Related issues:

• [C++] Array methods IsNull and IsValid are not complementary (supercedes)

PRs and other links:

• GitHub Pull Request #2091

_{Note: This issue was originally created as ARROW-2641. Please see the migration documentation for further details.}

[asfimport]

Robert Nishihara / @robertnishihara:
Most likely unrelated, but we memset some unused padding bytes to 0 in the c++ implementation to make the serialization deterministic. e.g., #405

[asfimport]

Wes McKinney / @wesm:
Issue resolved by pull request 2091
#2091

[asfimport]

Antoine Pitrou / @pitrou:
As a side note, though, the fact that our IPC code can write out uninitialized memory /might/ have adverse security consequences.