Initially I built a set of ~40 migration plugins in the "config/install" directory of a custom module following a blog post tutorial. Because it was becoming a chore to reinstall the module to pick up changes I renamed the files and moved them to the module's "migrations" directory. At this point all of the custom migration plugins stopped showing in the GUI though, oddly enough, a few of them still showed up in the output of "drush migrate-status". I checked MigrationPluginManager::processDefinition() via a debugger, as suggested by someone in slack, and it only showed the items which had been identified, so the Drush example had four items while the UI had zero.
The yml files were originally created by duplicating various migrate templates from core and modifying as necessary. When they're named properly and are stored in "config/install" they load and work as intended, when they're in "migrations" they do not.
Closed: works as designed
4.0
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