[LUCENE-3624] Throw exception for "Multi-SortedSource" instead of returning null

• Type: Task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0-ALPHA
• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Robert Muir
• Created: 07/Dec/11 12:20
• Updated: 28/Aug/22 13:03
• Resolved: 07/Dec/11 17:13

Description

Spinoff of LUCENE-3623: currently if you addIndexes(FIR) or similar, you get a NPE deep within codecs during merge.

I think the NPE is confusing, it looks like a bug but a clearer exception would be an improvement.