Minor Description
It would be useful for the CollapsingQParserPlugin to support ValueSource collapse criteria.
Proposed syntax:
fq={!collapse field=collapse_field max=value_source}
This ticket will also introduce a function query called "cscore", which will return the score of the current document being collapsed. This will allow score to be incorporated into collapse criteria functions.
A simple example of the cscore usage:
fq={!collapse field=collapse_field max=sum(cscore(), field(x))}