[HUDI-4476] Improve code quality around partition path extraction and identifier

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Done
• Fix Version/s: 0.12.0
• Component/s: metadata
• Epic Link: Metadata Table for File Listing & Query Planning
• Assignee: Sagar Sumit
• Reporter: Ethan Guo (this is the old account; please use "yihua")
• Created: 26/Jul/22 05:22
• Updated: 16/Feb/23 05:58
• Resolved: 26/Jul/22 16:14

Description

For an empty relative partition path in non-partitioned table, we use "." as the partition path identifier in the metadata table records.  In the code, there are various ways of doing such conversion, which makes it hard to reason about.  There is one bug caused by such complexity:  https://github.com/apache/hudi/pull/6113. We should standardize the way of such handling and make the code more readable.