[LUCENE-3420] assertion derived class modifier from parent class silently breaks backward compatibility

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 3.3
• Component/s: core/index
• Lucene Fields: New
• Assignee: Uwe Schindler
• Reporter: John Wang
• Created: 07/Sep/11 19:04
• Updated: 28/Aug/22 12:56
• Resolved: 18/Sep/11 09:02

Description

after upgrading to lucene 3.1+, I see this in my log:

java.lang.AssertionError: TokenStream implementation classes or at least their incrementToken() implementation must be final
at org.apache.lucene.analysis.TokenStream.assertFinal(TokenStream.java:117)
at org.apache.lucene.analysis.TokenStream.<init>(TokenStream.java:92)

Turns out I derived TokenStream and my class was not declared final.

This silently breaks backward compatibility via reflection, scary...

I think doing this sort of check is fine, but throwing an java.lang.AssertionError in this case is too stringent.

This is a style check against lucene clients, a error log would be fine, but throwing an Error is too much.

See constructor implementation for: http://svn.apache.org/viewvc/lucene/dev/branches/branch_3x/lucene/src/java/org/apache/lucene/analysis/TokenStream.java?view=markup