Incremental reindex! fails with NoMethodError: undefined method `task_id' for nil:NilClass

[metheglin]

• Rails version: 7.0.2
• Algolia Rails integration version: 3.0.0
• Algolia Client Version: 3.7.1
• Language Version:

Description

This error happens because I'm using conditional index.
In reindex!, if any records to be deleted, it deletes from algolia and remove from activerecord target.

algoliasearch-rails/lib/algoliasearch-rails.rb

Line 453 in f8f599d

AlgoliaSearch.client.delete_objects(index_name, ids.select { |id| !id.blank? })

And then the rest of activerecord target to be saved.

algoliasearch-rails/lib/algoliasearch-rails.rb

Line 464 in f8f599d

last_task = AlgoliaSearch.client.save_objects(index_name, objects).last.task_id

But when all of the activerecord target to be deleted, there is nothing to be saved. Thus AlgoliaSearch.client.save_objects(index_name, objects) returns empty array. And then .last got nil, then .task_id got undefined method task_id.

Please check PR for better understanding. #452

Steps To Reproduce

class Product < ApplicationRecord
  enum status: {
    draft: 0,
    opened: 1,
  }

  algoliasearch if: :algolia_published? do
    attribute :title
    attribute :content
  end

  def algolia_published?
    opened?
  end
end

in rails console for instance

Product.draft.limit(3).reindex!

Got the error below

NoMethodError: undefined method `task_id' for nil:NilClass

/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/algoliasearch-rails-3.0.0/lib/algoliasearch-rails.rb:464:in `block (2 levels) in algolia_reindex!'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/activerecord-7.0.2.3/lib/active_record/relation/batches.rb:138:in `block in find_in_batches'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/activerecord-7.0.2.3/lib/active_record/relation/batches.rb:245:in `block in in_batches'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/activerecord-7.0.2.3/lib/active_record/relation/batches.rb:229:in `loop'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/activerecord-7.0.2.3/lib/active_record/relation/batches.rb:229:in `in_batches'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/activerecord-7.0.2.3/lib/active_record/relation/batches.rb:137:in `find_in_batches'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/activerecord-7.0.2.3/lib/active_record/querying.rb:22:in `find_in_batches'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/algoliasearch-rails-3.0.0/lib/algoliasearch-rails.rb:913:in `algolia_find_in_batches'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/algoliasearch-rails-3.0.0/lib/algoliasearch-rails.rb:449:in `block in algolia_reindex!'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/algoliasearch-rails-3.0.0/lib/algoliasearch-rails.rb:442:in `each'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/algoliasearch-rails-3.0.0/lib/algoliasearch-rails.rb:442:in `algolia_reindex!'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/activerecord-7.0.2.3/lib/active_record/relation/delegation.rb:108:in `public_send'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/activerecord-7.0.2.3/lib/active_record/relation/delegation.rb:108:in `block in method_missing'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/activerecord-7.0.2.3/lib/active_record/relation.rb:880:in `_scoping'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/activerecord-7.0.2.3/lib/active_record/relation.rb:428:in `scoping'
/Users/metheglin/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/activerecord-7.0.2.3/lib/active_record/relation/delegation.rb:108:in `method_missing'

... (Logs continue but let me refrain from share because it includes project information)