rails7からrails6にダウングレードした #Rails

Gemfileのバージョン変更

-  gem "rails", "~> 7.0.2", ">= 7.0.2.3"
+  gem 'rails', '~> 6.0.4', '>= 6.0.4.7'

コマンド実行

$ bundle update
$ rails app:update (全てYES)

$ rails s -b 0.0.0.0するとエラー起きるので、以下２点修正。

Gemfileにgem ‘listen’追加

group :development do
  # Use console on exceptions pages [https://github.com/rails/web-console]
  gem "web-console"
  gem 'listen'
end

config.ruからRails.application.load_server削除

config.ru

- Rails.application.load_server

マイグレーションしていきます。

$ rails db:reset
$ rails db:migrate

rails aborted!
ArgumentError: Unknown migration version "7.0"; expected one of "4.2", "5.0", "5.1", "5.2", "6.0"

db/migrate/****_create_users.rb

-  class CreateUsers < ActiveRecord::Migration[7.0]
+  class CreateUsers < ActiveRecord::Migration[6.0]

rails aborted!
NoMethodError: undefined method `define' for #ActiveRecord::Migration:0x0000ffff82c040e0
Did you mean? defined?

db/schemes.rb

-  ActiveRecord::Schema[7.0].define(version: 2022_03_30_XXXXX) do
+  ActiveRecord::Schema.define(version: 2022_03_30_XXXXX) do

rails aborted!
NameError: undefined local variable or method `primary_abstract_class'

models/application_record.rb

class ApplicationRecord < ActiveRecord::Base
-  primary_abstract_class
+  self.abstract_class = true
end

やったー！！