Tasks to deprecate Migrate Drupal

Problem/Motivation

Track the steps needed to remove extension Migrate Drupal from core to contrib. See Remove a core module and move it to a contributed project of the deprecation policy.

Policy issue: #3371229: [Policy] Move Migrate Drupal and Migrate Drupal UI to contrib

This issue/plan is about the migrate_drupal core module which "provides a framework to migrate data from previous versions of Drupal into the site." It is not about removing the Migrate API from core.

Remaining tasks

1. Begin finding someone to maintain the contrib version of the extension.
2. Create a meta child issue for each module, should this be done by module?, with migrations to address moving the following to Migrate Drupal.
   • Migration state file
   • Source plugins and relevant tests. There are 100 source plugins to move.
   • Field plugins and relevant tests There are 18 plugins to move.
   • Process plugins and relevant tests. There are 49 plugins to move.
   • Destination plugins and relevant tests. here are 18 plugins to move.
   • migrations and relevant tests
3. Move integrations implemented by other modules to the extension. Create child issues or child meta issues, as needed, to address the following points. Not all points will apply to all extensions.
   • Move non-migration tests to the extensions.
   • Move Help Topics to the extensions.
   • Remove the extension from one or more profiles.
   • Removing references to the extensions from database dumps.
   • Update Update path tests. See Writing Automated Update Tests for Drupal 8 (or later) for details.
   • Remove templates from the extension’s markup.
     • Remove templates from themes that are staying in core, leave them in deprecated themes
     • Keep skipping the template in the stable copies test.
4. Do a thorough search of core for any remaining references to the extension. If references are found, outside of the extension, then create issues to remove the references.
5. Create the contrib project with a stable release.
6. Create an issue to Deprecate the core extension. Use the Issue Summary template or core extension deprecation.