Migrate field collections with same ID and revision IDs as D7

field-collection-migration-keep-ids.patch

diff --git a/migrations/d7_field_collection.yml b/migrations/d7_field_collection.yml
index a7077d3..4c9be52 100644
--- a/migrations/d7_field_collection.yml
+++ b/migrations/d7_field_collection.yml
@@ -8,6 +8,8 @@ deriver: Drupal\paragraphs\Plugin\migrate\D7FieldCollectionItemDeriver
 source:
   plugin: d7_field_collection_item
 process:
+  id: item_id
+  revision_id: revision_id
   type: bundle
   # @todo Get the langcode from the parent entity.
   # See https://drupal.org/i/3146632.
diff --git a/migrations/d7_field_collection_revisions.yml b/migrations/d7_field_collection_revisions.yml
index 01ca0e3..2762f41 100644
--- a/migrations/d7_field_collection_revisions.yml
+++ b/migrations/d7_field_collection_revisions.yml
@@ -4,20 +4,12 @@ migration_tags:
   - Drupal 7
   - Content
   - Field Collection Revisions Content
-deriver: Drupal\paragraphs\Plugin\migrate\D7FieldCollectionItemDeriver
+deriver: Drupal\paragraphs\Plugin\migrate\D7FieldCollectionItemRevisionDeriver
 source:
   plugin: d7_field_collection_item_revision
 process:
-  id:
-    -
-      plugin: paragraphs_lookup
-      tags:
-        - Field Collection Content
-      source: item_id
-    -
-      plugin: extract
-      index:
-        - id
+  id: item_id
+  revision_id: revision_id
   type: bundle
   # @todo Get the langcode from the parent entity revision.
   # See https://drupal.org/i/3146632.
@@ -25,6 +17,3 @@ process:
 destination:
   plugin: entity_reference_revisions:paragraph
   new_revisions: TRUE
-migration_dependencies:
-  required:
-    - d7_field_collection
diff --git a/src/Plugin/migrate/D7FieldCollectionItemRevisionDeriver.php b/src/Plugin/migrate/D7FieldCollectionItemRevisionDeriver.php
new file mode 100644
index 0000000..ac747b9
--- /dev/null
+++ b/src/Plugin/migrate/D7FieldCollectionItemRevisionDeriver.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace Drupal\paragraphs\Plugin\migrate;
+
+use Drupal\Component\Plugin\Derivative\DeriverBase;
+use Drupal\Core\Database\DatabaseExceptionWrapper;
+use Drupal\Core\Plugin\Discovery\ContainerDeriverInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+use Drupal\migrate\Exception\RequirementsException;
+use Drupal\migrate\Plugin\MigrationDeriverTrait;
+use Drupal\migrate_drupal\FieldDiscoveryInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Deriver for field collections.
+ */
+class D7FieldCollectionItemRevisionDeriver extends D7FieldCollectionItemDeriver {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getDerivativeDefinitions($base_plugin_definition) {
+    $derivatives = parent::getDerivativeDefinitions($base_plugin_definition);
+
+    foreach ($derivatives as &$derivative) {
+      $derivative['migration_dependencies']['required'][] = 'd7_field_collection:' . $derivative['destination']['default_bundle'];
+    }
+    // "d7_field_collection:deferred_fees"
+    return $derivatives;
+  }
+
+}
diff --git a/src/Plugin/migrate/field/FieldCollection.php b/src/Plugin/migrate/field/FieldCollection.php
index 73d8b00..f511a0c 100644
--- a/src/Plugin/migrate/field/FieldCollection.php
+++ b/src/Plugin/migrate/field/FieldCollection.php
@@ -71,8 +71,9 @@ class FieldCollection extends FieldPluginBase {
     $dependencies = $migration->getMigrationDependencies() + ['required' => []];
     $dependencies['required'] = array_unique(array_merge(array_values($dependencies['required']), [$migration_dependency]));
     $migration->set('migration_dependencies', $dependencies);
-
-    if (strpos($migration->getDestinationPlugin()->getPluginId(), 'entity_revision:') === 0 || strpos($migration->getDestinationPlugin()->getPluginId(), 'entity_complete:') === 0) {
+    if (strpos($migration->getDestinationPlugin()->getPluginId(), 'entity_revision:') === 0 ||
+        strpos($migration->getDestinationPlugin()->getPluginId(), 'entity_complete:') === 0 ||
+        strpos($migration->getDestinationPlugin()->getPluginId(), 'entity_reference_revisions:') === 0) {
       $dependencies['required'] = array_unique(array_merge(array_values($dependencies['required']), [$migration_rev_dependency]));
       $migration->set('migration_dependencies', $dependencies);
     }