Fix loading schema cache when all databases have disabled database tasks

activerecord/lib/active_record/railtie.rb

@@ -147,6 +147,7 @@ class Railtie < Rails::Railtie # :nodoc:
         config.after_initialize do |app|
           ActiveSupport.on_load(:active_record) do
             db_config = ActiveRecord::Base.configurations.configs_for(env_name: Rails.env).first
+            next if db_config.nil?
 
             filename = ActiveRecord::Tasks::DatabaseTasks.cache_dump_filename(db_config)
 

railties/test/application/initializers/frameworks_test.rb

@@ -239,6 +239,23 @@ def show
       ActiveRecord::Base.connection.drop_table("posts", if_exists: true) # force drop posts table for test.
     end
 
+    test "skips checking for schema cache dump when all databases skipping database tasks" do
+      app_file "config/database.yml", <<-YAML
+        development:
+          database: storage/default.sqlite3
+          adapter: sqlite3
+          database_tasks: false
+      YAML
+
+      add_to_config <<-RUBY
+        config.eager_load = true
+      RUBY
+
+      assert_nothing_raised do
+        require "#{app_path}/config/environment"
+      end
+    end
+
     test "expire schema cache dump" do
       rails %w(generate model post title:string)
       rails %w(db:migrate db:schema:cache:dump db:rollback)