Rails db:reset Pagy gem エラーが出てしまう。

Question

ページネーションを実装したいと考えています。

Pagyというgemを導入して、db:resetをすると下記のうようなエラーが出てしまいます。

rails aborted!
NameError: uninitialized constant Pagy
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/active_support.rb:80:in `block in load_missing_constant'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/active_support.rb:9:in `without_bootsnap_cache'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/active_support.rb:80:in `rescue in load_missing_constant'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/active_support.rb:59:in `load_missing_constant'
/api/config/initializers/pagy.rb:1:in `<main>'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:55:in `load'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:55:in `load'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/engine.rb:666:in `block in load_config_initializer'
/usr/local/bundle/gems/activesupport-6.0.3.1/lib/active_support/notifications.rb:182:in `instrument'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/engine.rb:665:in `load_config_initializer'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/engine.rb:625:in `block (2 levels) in <class:Engine>'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/engine.rb:624:in `each'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/engine.rb:624:in `block in <class:Engine>'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/initializable.rb:32:in `instance_exec'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/initializable.rb:32:in `run'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/initializable.rb:61:in `block in run_initializers'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/initializable.rb:50:in `each'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/initializable.rb:50:in `tsort_each_child'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/initializable.rb:60:in `run_initializers'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/application.rb:363:in `initialize!'
/api/config/environment.rb:5:in `<main>'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
/usr/local/bundle/gems/zeitwerk-2.3.0/lib/zeitwerk/kernel.rb:23:in `require'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/application.rb:339:in `require_environment!'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/application.rb:523:in `block in run_tasks_blocks'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/commands/rake/rake_command.rb:23:in `block in perform'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/commands/rake/rake_command.rb:20:in `perform'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/command.rb:48:in `invoke'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/commands.rb:18:in `<main>'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
bin/rails:4:in `<main>'

Caused by:
NameError: uninitialized constant Pagy
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/active_support.rb:61:in `block in load_missing_constant'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/active_support.rb:17:in `allow_bootsnap_retry'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/active_support.rb:60:in `load_missing_constant'
/api/config/initializers/pagy.rb:1:in `<main>'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:55:in `load'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:55:in `load'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/engine.rb:666:in `block in load_config_initializer'
/usr/local/bundle/gems/activesupport-6.0.3.1/lib/active_support/notifications.rb:182:in `instrument'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/engine.rb:665:in `load_config_initializer'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/engine.rb:625:in `block (2 levels) in <class:Engine>'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/engine.rb:624:in `each'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/engine.rb:624:in `block in <class:Engine>'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/initializable.rb:32:in `instance_exec'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/initializable.rb:32:in `run'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/initializable.rb:61:in `block in run_initializers'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/initializable.rb:50:in `each'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/initializable.rb:50:in `tsort_each_child'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/initializable.rb:60:in `run_initializers'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/application.rb:363:in `initialize!'
/api/config/environment.rb:5:in `<main>'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
/usr/local/bundle/gems/zeitwerk-2.3.0/lib/zeitwerk/kernel.rb:23:in `require'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/application.rb:339:in `require_environment!'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/application.rb:523:in `block in run_tasks_blocks'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/commands/rake/rake_command.rb:23:in `block in perform'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/commands/rake/rake_command.rb:20:in `perform'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/command.rb:48:in `invoke'
/usr/local/bundle/gems/railties-6.0.3.1/lib/rails/commands.rb:18:in `<main>'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
/usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
bin/rails:4:in `<main>'
Tasks: TOP => db:reset => db:drop => db:load_config => environment
(See full trace by running task with --trace)

Answer 1

Caused by:
NameError: uninitialized constant Pagy

エラーから、Pagyクラスが見つかっていないようです。

Pagy gemのセットアップガイド（How To | Pagy）の手順をもう一度みなおしてみるとよいかもしれません。

bundle installはされているとおもうのですが、ApplicationControllerやApplicationHelperにPagyのモジュールのincludeが必要なので、その部分を確かめてみてください。

また、rails consoleを立ち上げて、Pagyと入力したときにPagyのクラスが返ってくれば上記のエラーは解消されているとおもいます。（Pagyクラスが見つからない場合はNameError (uninitialized constant Pagy)となるはず）