How to use `Searchkick.multi_search` along with `with_highlights`? undefined method `with_highlights'

We're trying to optimize our search requests by making a single bulk search, so we're trying to use Searchkick.multi_search. However, it only returns Searchkick::Query with the results populated in a results attribute, as a regular Array.

Then, now if I try results.with_highlights... it fails with

undefined method `with_highlights' for #<Array:0x000055a82a7440f0>

Or if I try on the search_query.with_highlights it fails with

undefined method `with_highlights' for #<Searchkick::Query:0x00007f47c5d0cde8>

How can I get the highlights when using multi_search?

Updated Answer for Searchkick 4.6.1+

Talked to Ankane from Searchkick here https://github.com/ankane/searchkick/pull/1518. He ended up releasing a new version with fixes to this then the original answer here is only valid up to Searchkick version 4.6.0.

For 4.6.1+ just do:

  groups = Group.search(query, execute: false)
  users = User.search(query, execute: false)

  Searchkick.multi_search([groups, users])

  highlighted_groups_results = groups.with_highlights(...
  ...

Original answer for 4.6.0-

Got it!

After diving into the Searchkick codebase and checking the Searchkick::Query implementation, discovered that the execute method is what I need.

def execute
    @execute ||= begin
                     begin
                       response = execute_search
                       if retry_misspellings?(response)
                         prepare
                         response = execute_search
                       end
                     rescue => e # TODO rescue type
                       handle_error(e)
                     end
                     handle_response(response)
                   end
end

https://github.com/ankane/searchkick/blob/230ec8eb996ae93af4dc7686e02555d995ba1870/lib/searchkick/query.rb#L101

handle_response(response) is exactly what we need for making with_highlights work.

Then my final implementation ended up being something like the following:

groups = Group.search(query, execute: false)
users = User.search(query, execute: false)

Searchkick.multi_search([groups, users])

# execute here won't do any additional requests as it's already cached in an instance variable @execute
highlighted_groups_results = groups.execute.with_highlights(...
...