Fix sync bug on conflicts

src/provider.rs

@@ -51,9 +51,9 @@ where
 
             let server_mod = cal_server.get_tasks_modified_since(Some(self.last_sync));
             let server_del = cal_server.get_items_deleted_since(self.last_sync);
-            let local_mod = cal_local.get_tasks_modified_since(Some(self.last_sync));
             let local_del = cal_local.get_items_deleted_since(self.last_sync);
 
+            // Pull remote changes from the server
             let mut tasks_to_add_to_local = Vec::new();
             let mut tasks_id_to_remove_from_local = Vec::new();
             for deleted_id in server_del {
@@ -66,10 +66,21 @@ where
                 }
                 tasks_to_add_to_local.push((*new_item).clone());
             }
+            // Even in case of conflicts, "the server always wins", so it is safe to remove tasks from the local cache as soon as now
+            remove_from_calendar(&tasks_id_to_remove_from_local, cal_local);
+
+
+
+            // Push local changes to the server
+            let local_mod = cal_local.get_tasks_modified_since(Some(self.last_sync));
 
             let mut tasks_to_add_to_server = Vec::new();
             let mut tasks_id_to_remove_from_server = Vec::new();
             for deleted_id in local_del {
+                if server_mod.contains_key(&deleted_id) {
+                    log::warn!("Conflict for task {}, that has been locally deleted and updated in the server. Using the server version.", deleted_id);
+                    continue;
+                }
                 tasks_id_to_remove_from_server.push(deleted_id);
             }
             for (new_id, new_item) in &local_mod {
@@ -80,7 +91,6 @@ where
                 tasks_to_add_to_server.push((*new_item).clone());
             }
 
-            remove_from_calendar(&tasks_id_to_remove_from_local, cal_local);
             remove_from_calendar(&tasks_id_to_remove_from_server, cal_server);
             move_to_calendar(&mut tasks_to_add_to_local, cal_local);
             move_to_calendar(&mut tasks_to_add_to_server, cal_server);

tests/sync.rs

@@ -45,11 +45,11 @@ fn print_calendar_list(cals: &Vec<Calendar>) {
 /// Populate sources with the following:
 /// * At the last sync: both sources had A, B, C, D, E, F, G, H, I, J, K, L, M at last sync
 /// * Before the newer sync, this will be the content of the sources:
-///     * server: A,    C, D,  E', F',  G✓, H , I',      K, L, M, N
+///     * server: A,    C, D,  E', F',  G✓, H , I',      K✓, L, M, N
-///     * cache:  A, B,    D', E,  F'', G , H✓, I✓, J✓, K, L, M,    O
+///     * cache:  A, B,    D', E,  F'', G , H✓, I✓, J✓,     L, M,    O
 ///
 /// Hence, here is the expected result after the sync:
-///     * both:   A,       D', E', F',  G✓, H✓, I',      K, L, M, N, O
+///     * both:   A,       D', E', F',  G✓, H✓, I',      K✓, L, M, N, O
 ///
 /// Notes:
 /// * X': name has been modified since the last sync
@@ -129,6 +129,9 @@ async fn populate_test_provider() -> Provider<Cache, Cache> {
 
     cal_server.delete_item(&task_j_id);
 
+    cal_server.get_item_by_id_mut(&task_k_id).unwrap().unwrap_task_mut()
+        .set_completed(true);
+
     let task_n = Item::Task(Task::new("task N (new from server)".into(), Utc::now()));
     cal_server.add_item(task_n);
 
@@ -154,6 +157,8 @@ async fn populate_test_provider() -> Provider<Cache, Cache> {
     cal_local.get_item_by_id_mut(&task_j_id).unwrap().unwrap_task_mut()
         .set_completed(true);
 
+    cal_local.delete_item(&task_k_id);
+
     let task_o = Item::Task(Task::new("task O (new from local)".into(), Utc::now()));
     cal_local.add_item(task_o);