Move PartialMatch field to Explanation struct and update related logic

[CascadingRadium]

• Previously, the PartialMatch field was returned for every hit, but this caused confusion in complex queries involving disjunctions and match queries. As a result, we moved PartialMatch to the score explanation, where each subquery's explanation will include its own PartialMatch. This field is set only if the query uses the DisjunctionSearcher or scorer.

[abhinavdangeti]

So just so we're clear here - partial_match will be set if an explicit disjunction were used and all its components did not match yes?
And also separately, if a match query resolves to a disjunction - and if some of the components did not match, we'll now be setting partial_match - correct?

[CascadingRadium]

• A match query will be a disjunction query over all the terms, and if the document has all
  the terms then partial_match will be set to false else it will be set to true.
• For all other queries partial_match will never show up in the search result as its omitempty and will be simply excluded from the search result.

[abhinavdangeti]

Ok, then I disagree with your proposal here - we should be returning a partial_match when a disjunction's component doesn't match as well.

[CascadingRadium]

like when the top-most query is a disjunction query ?

[abhinavdangeti]

like when the top-most query is a disjunction query ?

Ya.

[abhinavdangeti]

Per last conversation.

[CascadingRadium]

Actually, this approach has the limitation with disjunction + match queries
like so

{
  "disjuncts":[
    {
      "match":"termA termB"
    },
    {
      "match":"SONY PS5"
    }
  ]
}

where a single PartialMatch in the searchResult would lead to confusion regarding which component was partially matched (matchQuery1 / matchQuery2 / outerDisjuncts)

i will propose a new solution where the partialMatch is reflected in the score explanation, where each subQuery's expl will have the partialMatch attribute