[C++] Unions can not have 126 and 127 as type_codes

[asfimport]

Due to the following in builder_union.cc (Line 67-70)
 

type_id_to_children_.resize(union_type.max_type_code() + 1, nullptr);
 DCHECK_LT(
 type_id_to_children_.size(),
 static_cast<decltype(type_id_to_children_)::size_type>(UnionType::kMaxTypeCode));

and type.cc (Line 640-644)

uint8_t UnionType::max_type_code() const {
 return type_codes_.size() == 0
 ? 0
 : *std::max_element(type_codes_.begin(), type_codes_.end());
 }

 
In practice type codes of the union type must always be below or equal to 125 which is not intended behavior.

Reporter: Ian Alexander Joiner / @iajoiner
Assignee: Ian Alexander Joiner / @iajoiner

PRs and other links:

• GitHub Pull Request #10599

_{Note: This issue was originally created as ARROW-13154. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
Issue resolved by pull request 10599
#10599