Workbench Moderation to Content Moderation Migration

This module migrates the Workbench Moderation module in Drupal 8.4 to the Content Moderation module in Drupal 8.4.

This module is designed to execute the following 8 steps in a recoverable fashion:

1. States and transitions are stored in key value (i.e. the Workflow entity is created)
2. Entity state maps are stored in key value
3. WBM uninstalled
4. Workflows installed
5. CM installed
6. States and transitions are migrated (i.e. the Workflow entity is created)
7. Entity state maps are migrated
8. Remove all temporary data from key value used for the migration.

If any step fails, the opportunity should be there for a human to recover from the failed point and re-run the migration without having to start the process over.

Disclaimer

This module is experimental and should NOT be used on a live production system. Thoroughly test before running. Recovery of data is NOT guaranteed.

Tested Scenarios

This module so far has only been tested with the [https://github.com/josephdpurcell/drupal8_wbm2cm_concept-project](WBM2CM Drupal Profile) which constructs a scenario where a content type has Workbench Moderation enabled on 3 entities, and those entities are successfully migrated to Content Moderation.

A single test was done by enabling translations on the Page content type, adding a French translation, and success state was that post-migration the translation retained the moderation state it previously had.

Untested Test Scenarios

• Large data sets (i.e. > 1,000,000 entities)
• Workbench Moderation enabled on multiple entities with different workflows
• Forward revisions, e.g. an entity that is published and has a draft revision waiting to be published
• Forward revisions on translations
• Translations that have multiple revisions each with different moderation states
• Recovery scenarios, most notably ability to re-run the recreation of the state map if an entity save fails

Improvements

• Validate the migration before beginning
• Follow the Search API pattern for use of batch api to allow arbitrary tasks to be defined and processed

Known Bugs

• When using this module with the https://github.com/josephdpurcell/drupal8_wbm2cm_concept-project install profile the body field is not visible at /node/{id}/edit. At present, it's unclear whether that is an issue with the migration, the install profile, or something else.