Summary

Hybrid search ($scoreFusion / $rankFusion) on a view whose input pipelines mix a legacy $search with an extension $vectorSearch fails with Location65160 -- the extension $vectorSearch's index is not forwarded to mongot.

Description

In the with_mongot_extension_* suites, $vectorSearch runs through the extension (featureFlagVectorSearchExtension: true) while $search remains legacy (featureFlagSearchExtension: false). When both appear as input pipelines of a single $scoreFusion/$rankFusion executed against a view, the query fails:

Executor error during aggregate command on namespace: test.score\_fusion\_on\_view\_multi\_search\_view
:: caused by :: remote error from mongot: "index" is required
code: 65160, codeName: "Location65160"

Example failing pipeline (the multi_search case):

db..aggregate\(\[{
  $scoreFusion: {
    input: {
      pipelines: {
        a: \[{$search: {index: "searchIndex2", text: {query: "bar", path: "m"}}}\],
        b: \[{$vectorSearch: {queryVector: \[...\], path: "v", numCandidates: 60, index: "vectorSearchIndex1", limit: 60}}\]
      },
      normalization: "sigmoid"
    },
    combination: {method: "avg"}
  }
}\]\)

Pure-$search and pure-$vectorSearch hybrid queries on the same view pass; only the mixed (one legacy + one extension mongot stage) case fails, which points at the extension $vectorSearch losing its index during view resolution / request assembly when combined with a legacy mongot stage.

Environment

* Suites: with_mongot_extension_single_node (fails); not observed on sharded topologies in the same run (those aborted earlier on other failures -- confirm whether it also reproduces there).
* Flag: featureFlagExtensionsInsideHybridSearch: true (latent with it off, since the IFR kickback falls back to legacy $vectorSearch).

Failing tests (currently excluded)

* jstests/with_mongot/e2e/hybridSearch/score_fusion_on_view.js
* jstests/with_mongot/e2e/hybridSearch/ranked_fusion_on_view.js

Acceptance criteria

Remove the exclusion for these two tests from buildscripts/resmokeconfig/matrix_suites/overrides/with_mongot_extension.yml (regenerate matrix suites) and they pass in the with_mongot_extension_* suites with the flag on.