From a2a66300d99ed53d63a7f065ffbed53d2ce074e3 Mon Sep 17 00:00:00 2001
From: Matt Jankowski <matt@jankowski.online>
Date: Tue, 11 Apr 2023 11:25:29 +0200
Subject: [PATCH] Clean up the post deployment migration generator (#24233)

---
 .../post_deployment_migration/USAGE           | 10 +++++++
 .../post_deployment_migration_generator.rb    | 17 ++++++++++++
 .../templates/migration.erb                   |  8 ++++++
 .../post_deployment_migration_generator.rb    | 17 ------------
 .../post_deployment_migration/migration.rb    |  8 ------
 ...ost_deployment_migration_generator_spec.rb | 27 +++++++++++++++++++
 6 files changed, 62 insertions(+), 25 deletions(-)
 create mode 100644 lib/generators/post_deployment_migration/USAGE
 create mode 100644 lib/generators/post_deployment_migration/post_deployment_migration_generator.rb
 create mode 100644 lib/generators/post_deployment_migration/templates/migration.erb
 delete mode 100644 lib/generators/post_deployment_migration_generator.rb
 delete mode 100644 lib/templates/rails/post_deployment_migration/migration.rb
 create mode 100644 spec/generators/post_deployment_migration_generator_spec.rb

diff --git a/lib/generators/post_deployment_migration/USAGE b/lib/generators/post_deployment_migration/USAGE
new file mode 100644
index 00000000000..57f3c6aa1c3
--- /dev/null
+++ b/lib/generators/post_deployment_migration/USAGE
@@ -0,0 +1,10 @@
+Description:
+    Generate a Rails migration in the db/post_migrate/ dir.
+
+    Interacts with the post_deployment_migrations initializer.
+
+Example:
+    bin/rails generate post_deployment_migration IsolateChanges
+
+    Creates a migration in db/post_migrate/<timestamp>_isolate_changes.rb
+    which will have `disable_ddl_transaction!` and a `change` method included.
diff --git a/lib/generators/post_deployment_migration/post_deployment_migration_generator.rb b/lib/generators/post_deployment_migration/post_deployment_migration_generator.rb
new file mode 100644
index 00000000000..adb34a28960
--- /dev/null
+++ b/lib/generators/post_deployment_migration/post_deployment_migration_generator.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+require 'rails/generators/active_record'
+
+class PostDeploymentMigrationGenerator < Rails::Generators::NamedBase
+  source_root File.expand_path('templates', __dir__)
+
+  include Rails::Generators::Migration
+
+  def create_post_deployment_migration
+    migration_template 'migration.erb', "db/post_migrate/#{file_name}.rb"
+  end
+
+  def self.next_migration_number(path)
+    ActiveRecord::Generators::Base.next_migration_number(path)
+  end
+end
diff --git a/lib/generators/post_deployment_migration/templates/migration.erb b/lib/generators/post_deployment_migration/templates/migration.erb
new file mode 100644
index 00000000000..fd6a02a0f7d
--- /dev/null
+++ b/lib/generators/post_deployment_migration/templates/migration.erb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+class <%= migration_class_name %> < ActiveRecord::Migration[<%= ActiveRecord::Migration.current_version %>]
+  disable_ddl_transaction!
+
+  def change
+  end
+end
diff --git a/lib/generators/post_deployment_migration_generator.rb b/lib/generators/post_deployment_migration_generator.rb
deleted file mode 100644
index 798c01b883a..00000000000
--- a/lib/generators/post_deployment_migration_generator.rb
+++ /dev/null
@@ -1,17 +0,0 @@
-# frozen_string_literal: true
-
-require 'rails/generators'
-
-module Rails
-  class PostDeploymentMigrationGenerator < Rails::Generators::NamedBase
-    def create_migration_file
-      timestamp = Time.zone.now.strftime('%Y%m%d%H%M%S')
-
-      template 'migration.rb', "db/post_migrate/#{timestamp}_#{file_name}.rb"
-    end
-
-    def migration_class_name
-      file_name.camelize
-    end
-  end
-end
diff --git a/lib/templates/rails/post_deployment_migration/migration.rb b/lib/templates/rails/post_deployment_migration/migration.rb
deleted file mode 100644
index 503205b8415..00000000000
--- a/lib/templates/rails/post_deployment_migration/migration.rb
+++ /dev/null
@@ -1,8 +0,0 @@
-# frozen_string_literal: true
-
-class <%= migration_class_name %> < ActiveRecord::Migration[5.2]
-  disable_ddl_transaction!
-
-  def change
-  end
-end
diff --git a/spec/generators/post_deployment_migration_generator_spec.rb b/spec/generators/post_deployment_migration_generator_spec.rb
new file mode 100644
index 00000000000..d552880e3bd
--- /dev/null
+++ b/spec/generators/post_deployment_migration_generator_spec.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+require 'rails/generators/testing/behaviour'
+require 'rails/generators/testing/assertions'
+
+require 'generators/post_deployment_migration/post_deployment_migration_generator'
+
+describe PostDeploymentMigrationGenerator, type: :generator do
+  include Rails::Generators::Testing::Behaviour
+  include Rails::Generators::Testing::Assertions
+  include FileUtils
+
+  tests described_class
+  destination File.expand_path('../../tmp', __dir__)
+  before { prepare_destination }
+  after { rm_rf(destination_root) }
+
+  describe 'the migration' do
+    it 'generates expected file' do
+      run_generator %w(Changes)
+
+      assert_migration('db/post_migrate/changes.rb', /disable_ddl/)
+      assert_migration('db/post_migrate/changes.rb', /change/)
+    end
+  end
+end