Support deleting related model when saving a model

Author: BastianLedererIcinga

library/Notifications/Common/EntityManager.php

@@ -198,6 +198,15 @@ protected function saveGraph(Model $model): void
 
             $this->saveLinks($relation, $model, $targets);
         }
+
+        // 5. Deletions queued on this model via Model::deleteOnSave(). A child dropped from a hasMany
+        //    relation is not removed by the cascade above, so it is deleted explicitly here — within the
+        //    same transaction, and only for entries the caller asked to delete (never a whole relation).
+        foreach ($model->getPendingDeletions() as $deletion) {
+            $this->delete($deletion);
+        }
+
+        $model->clearPendingDeletions();
     }
 
     /**

library/Notifications/Common/Model.php

@@ -30,6 +30,13 @@ abstract class Model extends \ipl\Orm\Model
      */
     private bool $resolvingProperty = false;
 
+    /**
+     * Related models queued to be deleted the next time this model is persisted
+     *
+     * @var list<Model>
+     */
+    private array $pendingDeletions = [];
+
     /**
      * Get whether this entity is new, i.e. not yet persisted to the database
      *
@@ -94,6 +101,42 @@ public function markClean(): static
         return $this;
     }
 
+    /**
+     * Queue a related model to be deleted the next time this model is persisted
+     *
+     * @param Model $model
+     *
+     * @return $this
+     */
+    public function deleteOnSave(Model $model): static
+    {
+        $this->pendingDeletions[] = $model;
+
+        return $this;
+    }
+
+    /**
+     * Get the related models queued for deletion via {@see deleteOnSave()}
+     *
+     * @return list<Model>
+     */
+    public function getPendingDeletions(): array
+    {
+        return $this->pendingDeletions;
+    }
+
+    /**
+     * Forget any models queued for deletion via {@see deleteOnSave()}
+     *
+     * @return $this
+     */
+    public function clearPendingDeletions(): static
+    {
+        $this->pendingDeletions = [];
+
+        return $this;
+    }
+
     protected function getProperty(string $key): mixed
     {
         $wasResolving = $this->resolvingProperty;

test/php/library/Notifications/Common/EntityManagerTest.php

@@ -173,6 +173,33 @@ public function testHasManyCascadeCopiesParentKeyIntoChildren()
         );
     }
 
+    public function testDeleteOnSaveRemovesAChildDroppedFromAHasManyRelation()
+    {
+        $workshop = new Workshop();
+        $workshop->name = 'Acme';
+
+        $spanner = new Gadget();
+        $spanner->name = 'Spanner';
+        $wrench = new Gadget();
+        $wrench->name = 'Wrench';
+        $workshop->gadgets = [$spanner, $wrench];
+
+        $this->em()->save($workshop);
+
+        $workshop->gadgets = [$spanner];
+        $workshop->deleteOnSave($wrench);
+
+        $this->em()->save($workshop);
+
+        $this->assertSame(
+            [['name' => 'Spanner', 'workshop_id' => $workshop->id]],
+            $this->rows('SELECT name, workshop_id FROM gadget ORDER BY id'),
+            'Only the queued child is deleted; its siblings are untouched'
+        );
+        $this->assertTrue($wrench->isNew(), 'The deleted model is marked new again');
+        $this->assertSame([], $workshop->getPendingDeletions(), 'The queue is cleared after save');
+    }
+
     public function testBelongsToCascadeSavesParentFirst()
     {
         $gadget = new Gadget();