[SPARK-47972] Restrict CAST expression for collations

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0.0
• Fix Version/s: 4.0.0
• Component/s: SQL
• Labels: pull-request-available
• Epic Link: Collation support
• Assignee: Mihailo Milosevic
• Reporter: Mihailo Milosevic
• Created: 24/Apr/24 08:02
• Updated: 04/Jun/24 18:06
• Resolved: 03/Jun/24 23:17

Description

Current state of code allows for calls like CAST(1 AS STRING COLLATE UNICODE). We want to restrict CAST expression to only be able to cast to default collation string, and to only allow COLLATE expression to produce explicitly collated strings.

Issue Links

• links to: GitHub Pull Request #46474
• links to: GitHub Pull Request #46860