Prevent destructive action on production database

This PR introduces a key/value type store to Active Record that can be used for storing internal values. It is an alternative implementation to #21237 cc @sgrif @matthewd.

It is possible to run your tests against your production database by accident right now. While infrequently, but as an anecdotal data point, Heroku receives a non-trivial number of requests for a database restore due to this happening. In these cases the loss can be large.

To prevent against running tests against production we can store the "environment" version that was used when migrating the database in a new internal table. Before executing tests we can see if the database is a listed in `protected_environments` and abort. There is a manual escape valve to force this check from happening with environment variable `DISABLE_DATABASE_ENVIRONMENT_CHECK=1`.

1 files changed, 9 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/tasks/database_tasks.rb b/activerecord/lib/active_record/tasks/database_tasks.rb
index c0c29a618c..6318a0725d 100644
--- a/activerecord/lib/active_record/tasks/database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/database_tasks.rb
@@ -42,6 +42,13 @@ module ActiveRecord
 
       LOCAL_HOSTS    = ['127.0.0.1', 'localhost']
 
+      def check_protected_environments!
+        if !ENV['DISABLE_DATABASE_internal_metadata'] && ActiveRecord::Migrator.protected_environment?
+          raise ActiveRecord::ProtectedEnvironmentError.new(ActiveRecord::Migrator.last_stored_environment)
+        end
+      rescue ActiveRecord::NoDatabaseError
+      end
+
       def register_task(pattern, task)
         @tasks ||= {}
         @tasks[pattern] = task
@@ -204,6 +211,8 @@ module ActiveRecord
         else
           raise ArgumentError, "unknown format #{format.inspect}"
         end
+        ActiveRecord::InternalMetadata.create_table
+        ActiveRecord::InternalMetata.store("environment" => ActiveRecord::ConnectionHandling::DEFAULT_ENV.call)
       end
 
       def load_schema_for(*args)