Merge pull request rails#48012 from fatkodima/mysql-adapter-load-hook

Add load hook for `ActiveRecord::ConnectionAdapters::Mysql2Adapter`

Author: guilleiguaran

activerecord/CHANGELOG.md

@@ -1,3 +1,10 @@
+*   Add a load hook for `ActiveRecord::ConnectionAdapters::Mysql2Adapter`
+    (named `active_record_mysql2adapter`) to allow for overriding aspects of the
+    `ActiveRecord::ConnectionAdapters::Mysql2Adapter` class. This makes `Mysql2Adapter`
+    consistent with `PostgreSQLAdapter` and `SQLite3Adapter` that already have load hooks.
+
+    *fatkodima*
+
 *   Introduce adapter for Trilogy database client
 
     Trilogy is a MySQL-compatible database client. Rails applications can use Trilogy

activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb

@@ -179,5 +179,6 @@ def default_prepared_statements
           false
         end
     end
+    ActiveSupport.run_load_hooks(:active_record_mysql2adapter, Mysql2Adapter)
   end
 end

guides/source/engines.md

@@ -1495,6 +1495,9 @@ These are the load hooks you can use in your own code. To hook into the initiali
 | `ActiveJob::TestCase`                | `active_job_test_case`               |
 | `ActiveRecord::Base`                 | `active_record`                      |
 | `ActiveRecord::TestFixtures`         | `active_record_fixtures`             |
+| `ActiveRecord::ConnectionAdapters::PostgreSQLAdapter`    | `active_record_postgresqladapter`    |
+| `ActiveRecord::ConnectionAdapters::Mysql2Adapter`        | `active_record_mysql2adapter`        |
+| `ActiveRecord::ConnectionAdapters::SQLite3Adapter`       | `active_record_sqlite3adapter`       |
 | `ActiveStorage::Attachment`          | `active_storage_attachment`          |
 | `ActiveStorage::VariantRecord`       | `active_storage_variant_record`      |
 | `ActiveStorage::Blob`                | `active_storage_blob`                |