diff -u b/core/modules/migrate/tests/src/Kernel/MigrateSourceTestBase.php b/core/modules/migrate/tests/src/Kernel/MigrateSourceTestBase.php
--- b/core/modules/migrate/tests/src/Kernel/MigrateSourceTestBase.php
+++ b/core/modules/migrate/tests/src/Kernel/MigrateSourceTestBase.php
@@ -146,18 +146,17 @@
     // All source plugins must define IDs.
     $this->assertNotEmpty($plugin->getIds());
 
-    if (is_null($expected_count)) {
-      $expected_count = count($expected_data);
-    }
-
     // If there is a high water mark, set it in the high water storage.
     if (isset($high_water)) {
       $this->container
         ->get('keyvalue')
         ->get('migrate:high_water')
-        ->set($this->migration->id(), $high_water);
+        ->set($this->migration->reveal()->id(), $high_water);
     }
 
+    if (is_null($expected_count)) {
+      $expected_count = count($expected_data);
+    }
     // If an expected count was given, assert it only if the plugin is
     // countable.
     if (is_numeric($expected_count)) {
only in patch2:
unchanged:
--- a/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php
+++ b/core/modules/migrate/src/Plugin/migrate/source/SqlBase.php
@@ -216,6 +216,7 @@ protected function initializeIterator() {
       $high_water_field = $this->getHighWaterField();
       $conditions->condition($high_water_field, $high_water, '>');
       $this->query->orderBy($high_water_field);
+      $condition_added = TRUE;
     }
     if ($condition_added) {
       $this->query->condition($conditions);