[ARROW-7512] [C++] Dictionary memo missing elements in id_to_dictionary_ map after deserialization

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: 0.15.0
• Component/s: C++
• External issue URL: https://github.com/apache/arrow/issues/23777
• Assignee: Unassigned
• Reporter: Wamsi Viswanath
• Created: 07/Jan/20 23:19
• Updated: 11/Jan/23 07:54
• Resolved: 31/Jan/20 01:56

Description

`id_to_dictionary_` map is empty after de-serialization of schema using ReadSchema method.

An example for reproduction:

https://gist.github.com/wamsiv/77dc1db44b5805828172e6c94d61d2d9

I see that it is probably being missed here: https://github.com/apache/arrow/blob/master/cpp/src/arrow/ipc/metadata_internal.cc#L804

Please let me know if the behavior is expected and if so then how the client is expected to have dictionary array values?