Admittedly this is a bit contrived, so not highest priority. But if we have an input pipeline with a score-generating stage ($text, $score, $search, etc.), then a $sort on any arbitrary non-score field, the score still exists as metadata but is no longer relevant in the $rankFusion computation.

However, since we see that the pipeline generates "score", we'll include that score as the "value" field in scoreDetails.

Likewise for the case that we have $search with score details, then a sort on a different field; we'll use the "searchScoreDetails" even though they weren't relevant to the rank.

Fixing this would require building some knowledge about "which part of the pipeline is responsible for the rank generation".

BLOCKED: Need to confirm with the product if they would like the score to be absent from scoreDetails in these cases where rank and score are not related, or if they would always like score present regardless for consistency. For example, one potential downside of this change would be if users write programatic / client side logic assuming score will always be present in rank fusions scoreDetails, but this change would break that assumption.