Issue #3068733 by blazey, amateescu, pmelab, hchonov: EntityStorageBase::loadMultiple returns unwanted entities when the static cache is warm

core/lib/Drupal/Core/Entity/EntityStorageBase.php

@@ -256,6 +256,7 @@ abstract class EntityStorageBase extends EntityHandlerBase implements EntityStor
    */
   public function loadMultiple(array $ids = NULL) {
     $entities = [];
+    $preloaded_entities = [];
 
     // Create a new variable which is either a prepared version of the $ids
     // array for later comparison with the entity cache, or FALSE if no $ids
@@ -271,16 +272,23 @@ abstract class EntityStorageBase extends EntityHandlerBase implements EntityStor
       $ids = array_keys(array_diff_key($flipped_ids, $entities));
     }
 
-    // Gather entities from a 'preload' method. This method can invoke a hook to
-    // be used by modules that need, for example, to swap the default revision
-    // of an entity with a different one. Even though the base entity storage
-    // class does not actually invoke any preload hooks, we need to call the
-    // method here so we can add the pre-loaded entity objects to the static
-    // cache below.
-    $preloaded_entities = $this->preLoad($ids);
+    // Try to gather any remaining entities from a 'preload' method. This method
+    // can invoke a hook to be used by modules that need, for example, to swap
+    // the default revision of an entity with a different one. Even though the
+    // base entity storage class does not actually invoke any preload hooks, we
+    // need to call the method here so we can add the pre-loaded entity objects
+    // to the static cache below. If all the entities were fetched from the
+    // static cache, skip this step.
+    if ($ids === NULL || $ids) {
+      $preloaded_entities = $this->preLoad($ids);
+    }
     if (!empty($preloaded_entities)) {
       $entities += $preloaded_entities;
 
+      // If any entities were pre-loaded, remove them from the IDs still to
+      // load.
+      $ids = array_keys(array_diff_key($flipped_ids, $entities));
+
       // Add pre-loaded entities to the cache.
       $this->setStaticCache($preloaded_entities);
     }

core/modules/workspaces/tests/src/Kernel/WorkspaceIntegrationTest.php

@@ -708,6 +708,18 @@ class WorkspaceIntegrationTest extends KernelTestBase {
       $this->assertEquals($expected_default_revision[$published_key], $entities[$entity_id]->isPublished());
     }
 
+    // Check loading entities one by one. It is important to do these checks
+    // after the "multiple load" ones above so we can test with a fully warmed
+    // static cache.
+    foreach ($expected_default_revisions as $expected_default_revision) {
+      $entity_id = $expected_default_revision[$id_key];
+      $entities = $this->entityTypeManager->getStorage($entity_type_id)->loadMultiple([$entity_id]);
+      $this->assertCount(1, $entities);
+      $this->assertEquals($expected_default_revision[$revision_key], $entities[$entity_id]->getRevisionId());
+      $this->assertEquals($expected_default_revision[$label_key], $entities[$entity_id]->label());
+      $this->assertEquals($expected_default_revision[$published_key], $entities[$entity_id]->isPublished());
+    }
+
     // Check \Drupal\Core\Entity\EntityStorageInterface::loadUnchanged().
     foreach ($expected_default_revisions as $expected_default_revision) {
       /** @var \Drupal\Core\Entity\RevisionableInterface|\Drupal\Core\Entity\EntityPublishedInterface $entity */