Inject migration and source plugin managers into the migration plugins

This is not going to be pretty because \Drupal is letting us get away with Drupal\migrate\Plugin\MigrationDeriverTrait

I don't think this needs a specific mention in the release notes

Here's a first effort.

Nice work, I can tell this wouldn't have come together so easily.

+++ b/core/modules/migrate/src/Plugin/MigrationDeriverTrait.php
@@ -31,7 +31,7 @@ public static function getSourcePlugin($source_plugin_id) {
+    return \Drupal::service('plugin.manager.migration')->createMigrationFromCustomDefinition($definition)->getSourcePlugin();

+++ b/core/modules/migrate/src/Plugin/MigrationPluginManager.php
@@ -223,4 +223,21 @@ protected function addDependency(array &$graph, $id, $dependency, $dynamic_ids)
+  public function createMigrationFromCustomDefinition(array $definition) {

I don't know about this going on the plugin manager, maybe we could put it in the trait until we solve the root of the issue? #2543552: Modernize migration source plugins Or, maybe we should call it createStubMigration()?

I think it is natural that the migration plugin manager creates migrations - so why not put it there? Patch attached changes the name to your suggestion and also refactors the method to be simpler and less vulnerable to code changes.

\Drupal::keyValue('migrate:high_water');
\Drupal::keyValue('migrate_status')->set($this->id(), $status);
\Drupal::keyValue('migrate_interruption_result')->get($this->id(), static::RESULT_INCOMPLETE);

Can we inject the key value service as well.

+++ b/core/modules/migrate/src/Plugin/MigrationPluginManager.php
@@ -226,18 +226,9 @@ protected function addDependency(array &$graph, $id, $dependency, $dynamic_ids)
+    return Migration::create(\Drupal::getContainer(), [], $id, $definition);

So much better! alexpott++

@benjy the reason I didn't inject state yet was because the need to inject the factory not each service - inject factories feels wrong... I'd rather have a MigrationState service or something that offers methods to access all the different migration state collections.

OK, that works for me.

Patch looks like a good step forward. I wanted to see if there were any other \Drupal:: calls to be removed, but couldn't find anything that should hold this going in.

Needs a re-roll after the change to Kernel tests - several hunks no longer apply.

Rerolled.

Looks good.

Committed/pushed to 8.2.x and cherry-picked to 8.1.x. Thanks!