Cannot paginate a dataset

[snacks02]

Hey! I'm a bit lost on this.

This is what I do:

Site.dataset.paginate(1, 25)

This is what I get:

SitesControllerTest#test_#all_sites_table_works:
Sequel::Error: You cannot paginate a dataset that already has a limit
    app/controllers/sites_controller.rb:269:in `all_sites_table'
    test/controllers/sites_controller_test.rb:248:in `block in <class:SitesControllerTest>'
    test/test_helper.rb:23:in `block in run'
    test/test_helper.rb:23:in `run'

These are the extensions I have loaded:

Sequel::Model.db.extension :pagination
Sequel::Model.db.extension :pg_array
Sequel::Model.db.extension :pg_enum
Sequel::Model.db.extension :pg_json
Sequel::Model.plugin :association_dependencies
Sequel::Model.plugin :validation_helpers
Sequel.extension :migration

What might cause this?

[AlexWayfer]

a dataset that already has a limit

Do you have default dataset/filters/limitations in the model? Or maybe spec helpers enables them?

[snacks02]

It doesn't happen in rails console, but in test_helper.rb I only have:

# frozen_string_literal: true

require "simplecov"

SimpleCov.start "rails" do
  add_filter "/app/channels/"
end

ENV["RAILS_ENV"] ||= "test"
require_relative "../config/environment"

require "rails/test_help"
require "fixture_dependencies/helper_methods"

class ActiveSupport::TestCase
  parallelize(workers: :number_of_processors)

  include FixtureDependencies::HelperMethods

  FixtureDependencies.fixture_path = "./test/fixtures"

  def run(*args, &)
    Sequel::Model.db.transaction(rollback: :always) { super }
  end
end

So I'm not sure what might be causing the issue.

[AlexWayfer]

Maybe something in nested files, like rails/test_help or fixture_dependencies/helper_methods. Maybe parallelization. Not sure either.

You can check the SQL, the exact limit may help you (dataset.to_sql, as I remember).

Also you can debug with break-points, even in spec helpers, via binding.pry or binding.irb, to detect which lines or files affect your default datasets.

[snacks02]

Thanks. I tried the suggestions, but they didn't help.

The query is:

SELECT * FROM "sites"

And when I do .dataset.paginate(1, 25), it is:

SELECT * FROM "sites" LIMIT 25 OFFSET 0

And it also doesn't happen when called inside binding.irb! Might be something to do with the context where it's called.

[AlexWayfer]

The query is:

I meant to check the query in the problematic place, before .paginate. Or maybe higher, upper in stack, you know. For example, in spec helper. If there are no changes to the dataset and no problems with paginate in the end of spec helper — yeah, probably something in specific spec file changes it. Some before hook? This hook still can be defined somewhere else, but I don't know ways to check when what part of dataset was changed/added, like call stack, so I see opportunity only in the deep debugging, if a place not obvious for you. Also, for example, you can also search for limit in all (spec/?) files, but this modification still can be even outside of project, what will be visible with the debugging and walking up and down along the stack.

[snacks02]

The issue is with Datagrid gem.

I wasn't able to find where it happens, but this results in the error:

# all_sites_grid.rb
class AllSitesGrid < BaseGrid
  scope do
    Site
  end
end

# sites_controller.rb
grid = AllSitesGrid.new do
  Site.dataset.paginate(1, 25)
end

While this works just fine:

# all_sites_grid.rb
class AllSitesGrid < BaseGrid
  scope do
    []
  end
end

# sites_controller.rb
grid = AllSitesGrid.new do
  Site.dataset.paginate(1, 25).to_a
end

This is a simplified representation of what was going in my case.