Add ability to open a synced realm without sync configuration.

CHANGELOG.md

@@ -1,3 +1,19 @@
+NEXT_RELEASE Release notes (YYYY-MM-DD)
+=============================================================
+
+### Fixed
+* None
+
+### Enhancements
+* Add `realm::db_config::enable_forced_sync_history()` which allows you to open a synced Realm
+  even if a sync configuration is not supplied.
+
+### Compatibility
+* Fileformat: Generates files with format v24. Reads and automatically upgrade from fileformat v10.
+
+### Internals
+* None
+
 2.2.0 Release notes (2024-07-22)
 =============================================================
 

include/cpprealm/internal/bridge/realm.hpp

@@ -199,6 +199,10 @@ namespace realm::internal::bridge {
             void set_schema_version(uint64_t version);
             void set_encryption_key(const std::array<char, 64>&);
             void should_compact_on_launch(std::function<bool(uint64_t total_bytes, uint64_t unused_bytes)>&& fn);
+            /// Open the Realm using the sync history mode even if a sync configuration is not supplied.
+            /// This mode is used for opening a synced realm with a local realm config in the scenario
+            /// that you do not have a valid sync user object.
+            void enable_forced_sync_history();
             std::optional<schema> get_schema();
 
             template<typename T>

include/cpprealm/networking/websocket.hpp

@@ -305,7 +305,7 @@ namespace realm::networking {
         configuration m_configuration;
     private:
         void initialize();
-        std::unique_ptr<::realm::sync::SyncSocketProvider> m_provider;
+        std::shared_ptr<::realm::sync::SyncSocketProvider> m_provider;
     };
 }
 

src/cpprealm/internal/bridge/realm.cpp

@@ -309,6 +309,10 @@ namespace realm::internal::bridge {
         get_config()->should_compact_on_launch_function = std::move(fn);
     }
 
+    void realm::config::enable_forced_sync_history() {
+        get_config()->force_sync_history = true;
+    }
+
     enum ::realm::client_reset_mode realm::config::get_client_reset_mode() const {
         return static_cast<enum ::realm::client_reset_mode>(get_config()->sync_config->client_resync_mode);
     }

src/cpprealm/networking/websocket.cpp

@@ -65,7 +65,7 @@ namespace realm::networking {
         auto user_agent_binding_info = std::string("RealmCpp/") + std::string(REALMCXX_VERSION_STRING);
         auto user_agent = util::format("RealmSync/%1 (%2) %3", REALM_VERSION_STRING, util::get_platform_info(),
                                        user_agent_binding_info);
-        m_provider = std::make_unique<::realm::sync::websocket::DefaultSocketProvider>(util::Logger::get_default_logger(), user_agent);
+        m_provider = std::make_shared<::realm::sync::websocket::DefaultSocketProvider>(util::Logger::get_default_logger(), user_agent);
     }
 
     std::unique_ptr<websocket_interface> default_socket_provider::connect(std::unique_ptr<websocket_observer> o, websocket_endpoint&& ep) {

tests/sync/flexible_sync_tests.cpp

@@ -102,6 +102,86 @@ TEST_CASE("flexible_sync", "[sync]") {
         auto flx_sync_config2 = user.flexible_sync_configuration();
         REQUIRE_THROWS(db(flx_sync_config2));
     }
+
+    SECTION("open synced realm without sync config") {
+        auto user = app.login(realm::App::credentials::anonymous()).get();
+        std::string realm_path = user.flexible_sync_configuration().path();
+
+        {
+            auto flx_sync_config = user.flexible_sync_configuration();
+            auto synced_realm = db(flx_sync_config);
+            auto update_success = synced_realm.subscriptions().update([](realm::mutable_sync_subscription_set &subs) {
+                subs.clear();
+            }).get();
+            CHECK(update_success == true);
+            CHECK(synced_realm.subscriptions().size() == 0);
+
+            update_success = synced_realm.subscriptions().update([](realm::mutable_sync_subscription_set &subs) {
+                        subs.add<AllTypesObject>("my-sub", [](auto &obj) {
+                            return obj.str_col == "a" && obj._id > 500 && obj._id < 520;
+                        });
+                        subs.add<AllTypesObjectLink>("foo-link");
+                    })
+                    .get();
+            CHECK(update_success == true);
+            CHECK(synced_realm.subscriptions().size() == 2);
+            synced_realm.get_sync_session()->wait_for_upload_completion().get();
+            synced_realm.get_sync_session()->wait_for_download_completion().get();
+
+            auto objs = synced_realm.objects<AllTypesObject>();
+            CHECK(objs.size() == 0);
+
+            synced_realm.write([&synced_realm]() {
+                AllTypesObject o;
+                o._id = 501;
+                o.str_col = "a";
+                synced_realm.add(std::move(o));
+            });
+
+            synced_realm.refresh();
+            synced_realm.get_sync_session()->wait_for_upload_completion().get();
+            synced_realm.get_sync_session()->wait_for_download_completion().get();
+            objs = synced_realm.objects<AllTypesObject>();
+            CHECK(objs.size() == 1);
+        }
+
+        {
+            auto local_config = realm::db_config();
+            local_config.set_path(realm_path);
+            local_config.enable_forced_sync_history();
+            auto local_realm = realm::open<AllTypesObject, AllTypesObjectLink, AllTypesObjectEmbedded>(local_config);
+            CHECK(local_realm.objects<AllTypesObject>().size() == 1);
+            local_realm.write([&local_realm]() {
+                AllTypesObject o;
+                o._id = 502;
+                o.str_col = "a";
+                local_realm.add(std::move(o));
+            });
+            // outside of subscription view, will be reverted once opened
+            // with a sync config.
+            local_realm.write([&local_realm]() {
+                AllTypesObject o;
+                o._id = 503;
+                o.str_col = "b";
+                local_realm.add(std::move(o));
+            });
+            CHECK(local_realm.objects<AllTypesObject>().size() == 3);
+        }
+
+        {
+            auto flx_sync_config = user.flexible_sync_configuration();
+            auto synced_realm = db(flx_sync_config);
+            CHECK(synced_realm.objects<AllTypesObject>().size() == 3);
+            auto subs_size = synced_realm.subscriptions().size();
+            CHECK(subs_size == 2);
+
+            synced_realm.get_sync_session()->wait_for_upload_completion().get();
+            synced_realm.get_sync_session()->wait_for_download_completion().get();
+            synced_realm.refresh();
+            CHECK(synced_realm.objects<AllTypesObject>().size() == 2);
+        }
+    }
+
 }
 
 template<typename T, typename Func>