mongodb/mongoid · error · ArgumentError

#{resolved_path} is nil on this document; cannot perform vec

Error message

#{resolved_path} is nil on this document; cannot perform vector search

What it means

Error "#{resolved_path} is nil on this document; cannot perform vector search" thrown in mongodb/mongoid.

Source

Thrown at lib/mongoid/search_indexable.rb:87

    # @param [ Integer ] limit The maximum number of results (default: 10).
    # @param [ Integer | nil ] num_candidates The number of candidates to
    #   consider during the ANN search; defaults to limit * 10.
    # @param [ true | false ] exact Use exact nearest-neighbor (ENN) search
    #   instead of ANN (default: false). When true, numCandidates is omitted.
    #   Required when using a flat vector search index.
    # @param [ Hash | nil ] filter An optional MongoDB filter to pre-filter
    #   candidates before scoring.
    # @param [ Array ] pipeline Additional aggregation stages to append after
    #   the vector search and score projection.
    #
    # @return [ Array<Mongoid::Document> ] matching documents, each with
    #   a populated +vector_search_score+ attribute.
    def vector_search(index: nil, path: nil, limit: 10, num_candidates: nil, exact: false, filter: nil, pipeline: []) # rubocop:disable Metrics/ParameterLists
      _index, resolved_path = self.class.send(:resolve_vector_index, index, path)
      query_vector = public_send(resolved_path)

      if query_vector.nil?
        raise ArgumentError,
              "#{resolved_path} is nil on this document; cannot perform vector search"
      end

      self_exclusion = { '$match' => { '_id' => { '$ne' => _id } } }
      post_pipeline = [ self_exclusion, { '$limit' => limit }, *Array(pipeline) ]
      effective_candidates = num_candidates || (limit * 10)

      self.class.vector_search(
        query_vector,
        index: index,
        path: path,
        limit: limit + 1,
        num_candidates: effective_candidates,
        exact: exact,
        filter: filter,
        pipeline: post_pipeline
      )
    end

View on GitHub (pinned to 0da0e23d71)

When it happens

Trigger: Thrown at lib/mongoid/search_indexable.rb:87 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of mongodb/mongoid@0da0e23d71 (2026-08-23). Data as JSON: /api/errors/16a17992da4161e7. Report an issue: GitHub.