[ARROW-13479] [Format] Make requirement around dense union offsets less ambiguous

• Type: Task
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: Format
• External issue URL: https://github.com/apache/arrow/issues/18760
• Assignee: Unassigned
• Reporter: Antoine Pitrou
• Created: 28/Jul/21 16:30
• Updated: 11/Jan/23 08:33

Description

Currently, the spec states that dense union offsets for each child array must be "in order / increasing". There is an ambiguity: should they be strictly increasing, or are equal values supported?

The C++ implementation currently considers that equal offsets are acceptable.