[SPARK-49275] Fix return type nullness of the xpath expression

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0.0
• Fix Version/s: 4.0.0, 3.5.3
• Component/s: SQL
• Labels: pull-request-available
• Assignee: Chenhao Li
• Reporter: Chenhao Li
• Created: 17/Aug/24 17:11
• Updated: 04/Sep/24 05:15
• Resolved: 02/Sep/24 06:20

Description

The `xpath` expression incorrectly marks its return type as array of non-null strings. However, it can actually return an array containing nulls. This can cause NPE in code generation, such as query `select coalesce(xpath(repeat('<a></a>', id), 'a')[0], '') from range(1, 2)`.

Issue Links

• links to: GitHub Pull Request #47796
• links to: GitHub Pull Request #47959