[LUCENE-4087] Provide consistent IW behavior for illegal meta data changes

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0-ALPHA
• Fix Version/s: 4.0-ALPHA, 4.1, 6.0
• Component/s: core/index
• Lucene Fields: New, Patch Available
• Assignee: Simon Willnauer
• Reporter: Simon Willnauer
• Created: 29/May/12 19:35
• Updated: 28/Aug/22 13:17
• Resolved: 08/Jun/12 21:09

Description

Currently IW fails late and inconsistent if field metadata like an already defined DocValues type or "un"-omitting norms.

we can approach this similar to how we handle consistent field number and:

• throw exception if indexOptions conflict (e.g. omitTF=true versus
  false) instead of silently dropping positions on merge
• same with omitNorms
• same with norms types and docvalues types
• still keeping field numbers consistent

this way we could eliminate all these traps and just give an
exception instead.