refactor!: throw exception if model cannot be soft deleted #371 (#34)

Covers the scenario where a listener or observer prevents a model from being
soft-deleted. When this happens, an exception is thrown as we cannot honour
the client's request and are in an invalid state.

src/Drivers/SoftDeleteDriver.php

@@ -23,6 +23,7 @@
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\SoftDeletes;
 use InvalidArgumentException;
+use RuntimeException;
 
 class SoftDeleteDriver extends StandardDriver
 {
@@ -81,11 +82,23 @@ public function persist(Model $model): bool
          * @see https://github.com/cloudcreativity/laravel-json-api/issues/371
          */
         if ($this->willSoftDelete($model)) {
+            assert(method_exists($model, 'getDeletedAtColumn'));
             $column = $model->getDeletedAtColumn();
             // save the original date so we can put it back later on.
             $deletedAt = $model->{$column};
             // delete the record so that deleting and deleted events get fired.
-            $model->delete();
+            $response = $model->delete();  // capture the response
+
+            // if a listener prevented the delete from happening, we need to throw as we are in an invalid state.
+            // developers should prevent this scenario from happening either through authorization or validation.
+            if ($response === false) {
+                throw new RuntimeException(sprintf(
+                    'Failed to soft delete model - %s:%s',
+                    $model::class,
+                    $model->getKey(),
+                ));
+            }
+
             // apply the original date back before saving, so that we keep date provided by the client.
             $model->{$column} = $deletedAt;
         }

tests/lib/Acceptance/SoftDeleteTest.php

@@ -332,6 +332,23 @@ public function testItDoesNotSoftDeleteOnUpdate(): void
         ]));
     }
 
+    public function testItDoesNotSoftDeleteOnUpdateIfListenerReturnsFalse(): void
+    {
+        $post = Post::factory()->create(['deleted_at' => null]);
+
+        $data = ['deletedAt' => now()->toJSON(), 'title' => 'Hello World!'];
+
+        Post::deleting(fn() => false);
+
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('Failed to soft delete model - App\Models\Post:' . $post->getKey());
+
+        $this->schema
+            ->repository()
+            ->update($post)
+            ->store($data);
+    }
+
     public function testItRestores(): void
     {
         $restored = false;