Allow Many.get after Many.delete (#356)

Author: jayvdb

butane/tests/many.rs

@@ -164,6 +164,11 @@ async fn delete_all_from_many(conn: ConnectionAsync) {
 
     post.tags.delete(&conn).await.unwrap();
 
+    // Verify that the tags are deleted from the Many object
+    let tags: Vec<&Tag> = post.tags.get().unwrap().collect();
+    assert_eq!(tags.len(), 0);
+
+    // Verify that the tags are deleted from the database
     let post2 = Post::get(&conn, post.id).await.unwrap();
     assert_eq!(post2.tags.load(&conn).await.unwrap().count(), 0);
 }

butane_core/src/many.rs

@@ -269,8 +269,8 @@ impl<T: DataObject> ManyOps<T> for Many<T> {
         .await?;
         self.new_values.clear();
         self.removed_values.clear();
-        // all_values is now out of date, so clear it
-        self.all_values = OnceLock::new();
+        // all_values is now out of date, so empty it
+        self.all_values = OnceLock::from(Vec::new());
         Ok(())
     }