[SPARK-46736] Retain empty protobuf message in schema for rpotobuf connector

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0.0
• Fix Version/s: 4.0.0
• Component/s: Protobuf
• Labels: pull-request-available
• Assignee: Chaoqin Li
• Reporter: Chaoqin Li
• Created: 16/Jan/24 19:50
• Updated: 30/Jan/24 02:02
• Resolved: 30/Jan/24 02:02

Description

Since Spark doesn't allow empty StructType, empty proto message type as field will be dropped by default. Introduce an option to allow retaining an empty message field by inserting a dummy column.

Issue Links

• links to: GitHub Pull Request #44643