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, 13 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/model_schema.rb b/activerecord/lib/active_record/model_schema.rb
index 5df67cdbe7..b82923494f 100644
--- a/activerecord/lib/active_record/model_schema.rb
+++ b/activerecord/lib/active_record/model_schema.rb
@@ -44,6 +44,19 @@ module ActiveRecord
 
       ##
       # :singleton-method:
+      # Accessor for the name of the internal metadata table. By default, the value is "active_record_internal_metadatas"
+      class_attribute :internal_metadata_table_name, instance_accessor: false
+      self.internal_metadata_table_name = "active_record_internal_metadatas"
+
+      ##
+      # :singleton-method:
+      # Accessor for an array of names of environments where destructive actions should be prohibited. By default,
+      # the value is ["production"]
+      class_attribute :protected_environments, instance_accessor: false
+      self.protected_environments = ["production"]
+
+      ##
+      # :singleton-method:
       # Indicates whether table names should be the pluralized versions of the corresponding class names.
       # If true, the default table name for a Product class will be +products+. If false, it would just be +product+.
       # See table_name for the full rules on table/class naming. This is true, by default.