Add a upgrader for tags

Since the acts-as-taggable-on migrations make use of the ActsAsTaggableOn class, we want to skip the tasks inside of these migrations. We renamed the tables anyway, but in order to be able to re-run these migrations without harm it makes sense to skip these migrations.

lib/alchemy/upgrader/four_point_one.rb

@@ -0,0 +1,29 @@
+require_relative 'tasks/harden_acts_as_taggable_on_migrations'
+
+module Alchemy
+  class Upgrader::FourPointOne < Upgrader
+    class << self
+      def harden_acts_as_taggable_on_migrations
+        desc 'Harden `acts_as_taggable_on_migrations`'
+        `bundle exec rake railties:install:migrations FROM=acts_as_taggable_on_engine`
+        Alchemy::Upgrader::Tasks::HardenActsAsTaggableOnMigrations.new.patch_migrations
+        `bundle exec rake db:migrate`
+      end
+
+      def alchemy_4_1_todos
+        notice = <<-NOTE
+
+        Changed tagging provider to Gutentag
+        ------------------------------------
+
+        The automatic updater that just ran updated all existing `acts_as_taggable_on_migrations`,
+        so that they don't blow up if the `acts_as_taggable_on` gem is no longer available.
+
+        All your existing tags have been migrated to `Gutentag::Tag`s.
+
+        NOTE
+        todo notice, 'Alchemy v4.1 changes'
+      end
+    end
+  end
+end

lib/alchemy/upgrader/tasks/harden_acts_as_taggable_on_migrations.rb

@@ -0,0 +1,27 @@
+require 'thor'
+
+module Alchemy::Upgrader::Tasks
+  class HardenActsAsTaggableOnMigrations < Thor
+    include Thor::Actions
+
+    no_tasks do
+      def patch_migrations
+        sentinel = /add_column.*/
+        aato_file = Dir.glob('db/migrate/*_add_taggings_counter_cache_to_tags.*.rb').first
+        if aato_file
+          inject_into_file aato_file,
+            "\n\n    # inserted by Alchemy CMS upgrader\n    return unless defined?(ActsAsTaggableOn)",
+            { after: sentinel, verbose: true }
+        end
+
+        sentinel = /def up/
+        aato_file = Dir.glob('db/migrate/*_change_collation_for_tag_names.*.rb').first
+        if aato_file
+          inject_into_file aato_file,
+            "\n    # inserted by Alchemy CMS upgrader\n    return unless defined?(ActsAsTaggableOn)\n",
+            { after: sentinel, verbose: true }
+        end
+      end
+    end
+  end
+end

lib/tasks/alchemy/upgrade.rake

@@ -4,7 +4,8 @@ require 'alchemy/version'
 namespace :alchemy do
   desc "Upgrades your app to AlchemyCMS v#{Alchemy::VERSION}."
   task upgrade: [
-    'alchemy:upgrade:prepare'
+    'alchemy:upgrade:prepare',
+    'alchemy:upgrade:4.1:run', 'alchemy:upgrade:4.1:todo'
   ] do
     Alchemy::Upgrader.display_todos
   end
@@ -33,5 +34,27 @@ namespace :alchemy do
         picture.update_column(:image_file_format, picture.image_file_format.to_s.chomp)
       end
     end
+
+    desc 'Upgrade Alchemy to v4.1'
+    task '4.1' => [
+      'alchemy:upgrade:prepare',
+      'alchemy:upgrade:4.1:run',
+      'alchemy:upgrade:4.1:todo'
+    ] do
+      Alchemy::Upgrader.display_todos
+    end
+
+    namespace '4.1' do
+      task run: ['alchemy:upgrade:4.1:harden_acts_as_taggable_on_migrations']
+
+      desc 'Harden acts_as_taggable_on migrations'
+      task harden_acts_as_taggable_on_migrations: [:environment] do
+        Alchemy::Upgrader::FourPointOne.harden_acts_as_taggable_on_migrations
+      end
+
+      task :todo do
+        Alchemy::Upgrader::FourPointOne.alchemy_4_1_todos
+      end
+    end
   end
 end