[jira] [Updated] (LUCENE-7996) Should we require positive scores?

["Adrien Grand (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/LUCENE-7996?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Adrien Grand updated LUCENE-7996:
---------------------------------
    Attachment: LUCENE-7996.patch

Here is a patch:
 - boosts must be positive.
 - AssertingScorer checks that scores are positive.
 - AssertingSimilarity checks that scores are positive regardless of the boost.
 - FunctionScoreQuery fails when the value source produces a negative value, but unfortunately this only occurs at runtime.

Any opinions?

> Should we require positive scores?
> ----------------------------------
>
>                 Key: LUCENE-7996
>                 URL: https://issues.apache.org/jira/browse/LUCENE-7996
>             Project: Lucene - Core
>          Issue Type: Wish
>            Reporter: Adrien Grand
>            Priority: Minor
>         Attachments: LUCENE-7996.patch
>
>
> Having worked on MAXSCORE recently, things would be simpler if we required that scores are positive. Practically, this would mean 
>  - forbidding/fixing similarities that may produce negative scores (we have some of them)
>  - forbidding things like negative boosts
>  - fixing the scoring formula of some queries like {{BoostingQuery}} (which subtracts a score to another score) so that the end result may never be negative
> So I'd be curious to have opinions whether this would be a sane requirement or whether we need to be able to cope with negative scores eg. because some similarities that we want to support produce negative scores by design.



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