diff --git a/core/modules/migrate/src/Plugin/migrate/source/SourcePluginBase.php b/core/modules/migrate/src/Plugin/migrate/source/SourcePluginBase.php
index 451be40..332769c 100644
--- a/core/modules/migrate/src/Plugin/migrate/source/SourcePluginBase.php
+++ b/core/modules/migrate/src/Plugin/migrate/source/SourcePluginBase.php
@@ -84,13 +84,6 @@
   protected $originalHighWater;
 
   /**
-   * List of source IDs to process.
-   *
-   * @var array
-   */
-  protected $idList = array();
-
-  /**
    * Whether this instance should cache the source count.
    *
    * @var bool
@@ -166,10 +159,6 @@ public function __construct(array $configuration, $plugin_id, $plugin_definition
       $this->originalHighWater = $this->migration->getHighWater();
     }
 
-    if ($id_list = $this->migration->get('idlist')) {
-      $this->idList = $id_list;
-    }
-
     // Don't allow the use of both highwater and track changes together.
     if ($this->highWaterProperty && $this->trackChanges) {
       throw new MigrateException('You should either use a highwater mark or track changes not both. They are both designed to solve the same problem');
@@ -198,6 +187,22 @@ protected function getModuleHandler() {
   }
 
   /**
+   * Get the list of IDs of the rows to be migrated.
+   *
+   * @return array
+   *   The list of IDs of the rows to be migrated.
+   */
+  protected function getIdList() {
+    if (!empty($this->configuration['id_list'])) {
+      if (count($this->getIds()) > 1) {
+        throw new \LogicException('Cannot filter on multi-value key.');
+      }
+      return $this->configuration['id_list'];
+    }
+    return [];
+  }
+
+  /**
    * {@inheritdoc}
    */
   public function prepareRow(Row $row) {
@@ -321,11 +326,11 @@ public function next() {
 
       // In case we have specified an ID list, but the ID given by the source is
       // not in there, we skip the row.
-      $id_in_the_list = $this->idList && in_array(reset($this->currentSourceIds), $this->idList);
-      if ($this->idList && !$id_in_the_list) {
+      $id_list = $this->getIdList();
+      $id_in_the_list = $id_list && in_array(reset($this->currentSourceIds), $id_list);
+      if ($id_list && !$id_in_the_list) {
         continue;
       }
-
       // Preparing the row gives source plugins the chance to skip.
       if ($this->prepareRow($row) === FALSE) {
         continue;
diff --git a/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php b/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php
index 2ff55d5..68700dc 100644
--- a/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php
+++ b/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php
@@ -105,19 +105,16 @@ protected function prepareQuery() {
 
     // If an ID list is provided, filter on it. This only works for single-value
     // keys, so throw an exception if the key is multi-value.
-    if (isset($this->configuration['idlist'])) {
-      $key = $this->getIds();
-      if (count($key) == 1) {
-        $field = key($key);
+    if ($id_list = $this->getIdList()) {
+      // \Drupal\migrate\Plugin\migrate\source\SourcePluginBase::__construct()
+      // ensures the idlist is single long.
+      foreach ($this->getIds() as $field => $definition) {
         // If a table alias was provided, prepend it in order to prevent
         // the possibility of 'ambiguous column' errors.
-        if (isset($key[$field]['alias'])) {
-          $field = $key[$field]['alias'] . '.' . $field;
+        if (isset($definition['alias'])) {
+          $field = $definition['alias'] . '.' . $field;
         }
-        $this->query->condition($field, $this->configuration['idlist'], 'IN');
-      }
-      else {
-        throw new \LogicException('Cannot filter on multi-value key.');
+        $this->query->condition($field, $id_list, 'IN');
       }
     }
 
diff --git a/core/modules/migrate_drupal/tests/src/Unit/source/d6/NodeIdListTest.php b/core/modules/migrate_drupal/tests/src/Unit/source/d6/NodeIdListTest.php
index 7c4d488..4e2afcb 100644
--- a/core/modules/migrate_drupal/tests/src/Unit/source/d6/NodeIdListTest.php
+++ b/core/modules/migrate_drupal/tests/src/Unit/source/d6/NodeIdListTest.php
@@ -20,7 +20,7 @@ class NodeIdListTest extends NodeTest {
     // The fake configuration for the source.
     'source' => array(
       'plugin' => 'd6_node',
-      'idlist' => array(1),
+      'id_list' => [1],
     ),
   );