When migrating a Rails 6.1 app to Rails 7, all calculated SGID change, which causes ActionText attachments to error out. SGIDs are generated using `Rails.application.key_generator.generate_key('signed_global_ids')`, which uses different settings.

blob_sgid_after_rails_upgrade.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  #gem "rails", "6.1"
  gem "rails", github: "rails/rails", branch: :main

  gem "sqlite3"
end

require "active_record/railtie"
require "active_storage/engine"
require "action_text/engine"
require "tmpdir"

class TestApp < Rails::Application
  config.load_defaults 6.1

  config.root = __dir__
  config.hosts << "example.org"
  config.eager_load = false
  config.session_store :cookie_store, key: "cookie_store_key"
  config.secret_key_base = "secret_key_base"

  config.active_storage.service = :local
  config.active_storage.service_configurations = {
    local: {
      root: Dir.tmpdir,
      service: "Disk"
    }
  }
  # Disable logging for a cleaner output
  config.logger = Logger.new(nil)
end

ENV["DATABASE_URL"] = "sqlite3::memory:"

Rails.application.initialize!

require ActiveStorage::Engine.root.join("db/migrate/20170806125915_create_active_storage_tables.rb").to_s

# Disable migration logging for a cleaner output
ActiveRecord::Migration.verbose = false
ActiveRecord::Schema.define do
  CreateActiveStorageTables.new.change

  create_table :users, force: true
end

class User < ActiveRecord::Base
  has_one_attached :profile
end

require "minitest/autorun"

class BugTest < Minitest::Test
  def test_blob_sgid_after_rails_upgrade
    user = User.create!(
      profile: {
        content_type: "text/plain",
        filename: "dummy.txt",
        io: ::StringIO.new("dummy"),
      }
    )
    puts "Rails version: #{Rails::VERSION::STRING}"
    rails_6_sgid = "eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaEpJalJuYVdRNkx5OTBaWE4wTFdGd2NDOUJZM1JwZG1WVGRHOXlZV2RsT2pwQ2JHOWlMekUvWlhod2FYSmxjMTlwYmdZNkJrVlUiLCJleHAiOm51bGwsInB1ciI6ImF0dGFjaGFibGUifX0=--aa099340e7af7ec6ce1af3866ade911ea22c7834"

    assert_equal rails_6_sgid, user.profile.blob.attachable_sgid
  end
end