diff --git a/core/modules/migrate/src/Plugin/migrate/process/Migration.php b/core/modules/migrate/src/Plugin/migrate/process/Migration.php
index 5787b37..64dd74f 100644
--- a/core/modules/migrate/src/Plugin/migrate/process/Migration.php
+++ b/core/modules/migrate/src/Plugin/migrate/process/Migration.php
@@ -11,6 +11,7 @@
 use Drupal\Core\Entity\EntityStorageInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\migrate\MigrateException;
+use Drupal\migrate\MigrateSkipProcessException;
 use Drupal\migrate\MigrateSkipRowException;
 use Drupal\migrate\Plugin\MigrateIdMapInterface;
 use Drupal\migrate\Plugin\MigratePluginManager;
@@ -76,6 +77,7 @@ public function transform($value, MigrateExecutable $migrate_executable, Row $ro
       $scalar = TRUE;
       $value = array($value);
     }
+    $this->skipOnEmpty($value);
     $self = FALSE;
     /** @var \Drupal\migrate\Entity\MigrationInterface[] $migrations */
     $migrations = $this->migrationStorage->loadMultiple($migration_ids);
@@ -147,4 +149,18 @@ public function transform($value, MigrateExecutable $migrate_executable, Row $ro
     throw new MigrateSkipRowException();
   }
 
+  /**
+   * Skip the migration process entirely if the value is FALSE.
+   *
+   * @param mixed $value
+   *   The incoming value to transform.
+   *
+   * @throws \Drupal\migrate\MigrateSkipProcessException
+   */
+  protected function skipOnEmpty($value) {
+    if (!array_filter($value)) {
+      throw new MigrateSkipProcessException();
+    }
+  }
+
 }
diff --git a/core/modules/migrate_drupal/config/install/migrate.migration.d6_comment.yml b/core/modules/migrate_drupal/config/install/migrate.migration.d6_comment.yml
index 4cfea2f..dc38654 100644
--- a/core/modules/migrate_drupal/config/install/migrate.migration.d6_comment.yml
+++ b/core/modules/migrate_drupal/config/install/migrate.migration.d6_comment.yml
@@ -9,29 +9,17 @@ source:
 process:
   cid: cid
   pid:
-    -
-      plugin: skip_process_on_empty
-      source: pid
-    -
-      plugin: migration
-      migration: d6_comment
-  entity_id:
     plugin: migration
-    migration: d6_node
-    source: nid
+    migration: d6_comment
+    source: pid
+  entity_id: nid
   entity_type: 'constants/entity_type'
   # field_name & comment_type is calculated in
   # \Drupal\migrate_drupal\Plugin\migrate\source\d6\Comment::prepareRow()
   field_name: field_name
   comment_type: comment_type
   subject: subject
-  uid:
-    -
-      plugin: skip_process_on_empty
-      source: uid
-    -
-      plugin: migration
-      migration: d6_user
+  uid: uid
   name: name
   mail: mail
   homepage: homepage
diff --git a/core/modules/migrate_drupal/config/install/migrate.migration.d6_profile_values.yml b/core/modules/migrate_drupal/config/install/migrate.migration.d6_profile_values.yml
index d6d0ab7..da0395e 100644
--- a/core/modules/migrate_drupal/config/install/migrate.migration.d6_profile_values.yml
+++ b/core/modules/migrate_drupal/config/install/migrate.migration.d6_profile_values.yml
@@ -7,10 +7,7 @@ source:
 load:
   plugin: drupal_entity
 process:
-  uid:
-    plugin: migration
-    migration: d6_user
-    source: uid
+  uid: uid
 destination:
   plugin: entity:user
 migration_dependencies: