feat: Get rid of "common extensions"

Common extensions are confusing, and they've included `e2ee` and `to-device` by default. This is not a sane default anymore,
now that there's the concept of `EncryptionSync`: it's either we have the encryption sync that enables e2ee and to-device +
a room list sync that doesn't, OR we have a single room list that has both.

Room List was misconfigured to always use `e2ee` and `to-device`, which was incorrect when it's running with the `EncryptionSync`
in the background. This is now removed, and properly tested.

bindings/matrix-sdk-ffi/src/sliding_sync.rs

@@ -813,12 +813,6 @@ impl SlidingSyncBuilder {
         Ok(Arc::new(builder))
     }
 
-    pub fn with_common_extensions(self: Arc<Self>) -> Arc<Self> {
-        let mut builder = unwrap_or_clone_arc(self);
-        builder.inner = builder.inner.with_common_extensions();
-        Arc::new(builder)
-    }
-
     pub fn without_e2ee_extension(self: Arc<Self>) -> Arc<Self> {
         let mut builder = unwrap_or_clone_arc(self);
         builder.inner = builder.inner.without_e2ee_extension();

crates/matrix-sdk-ui/src/room_list/mod.rs

@@ -80,7 +80,9 @@ use matrix_sdk::{
 pub use room::*;
 pub use room_list::*;
 use ruma::{
-    api::client::sync::sync_events::v4::{E2EEConfig, SyncRequestListFilters, ToDeviceConfig},
+    api::client::sync::sync_events::v4::{
+        AccountDataConfig, E2EEConfig, SyncRequestListFilters, ToDeviceConfig,
+    },
     assign,
     events::{StateEventType, TimelineEventType},
     OwnedRoomId, RoomId,
@@ -131,8 +133,12 @@ impl RoomListService {
     }
 
     async fn new_internal(client: Client, with_encryption: bool) -> Result<Self, Error> {
-        let mut builder =
-            client.sliding_sync("room-list").map_err(Error::SlidingSync)?.with_common_extensions();
+        let mut builder = client
+            .sliding_sync("room-list")
+            .map_err(Error::SlidingSync)?
+            .with_account_data_extension(
+                assign!(AccountDataConfig::default(), { enabled: Some(true) }),
+            );
 
         if with_encryption {
             builder = builder
@@ -459,4 +465,21 @@ mod tests {
 
         Ok(())
     }
+
+    #[async_test]
+    async fn test_no_to_device_and_e2ee_if_not_explicitly_set() -> Result<(), Error> {
+        let (client, _) = new_client().await;
+
+        let no_encryption = RoomListService::new(client.clone()).await?;
+        let extensions = no_encryption.sliding_sync.extensions_config();
+        assert_eq!(extensions.e2ee.enabled, None);
+        assert_eq!(extensions.to_device.enabled, None);
+
+        let with_encryption = RoomListService::new_with_encryption(client).await?;
+        let extensions = with_encryption.sliding_sync.extensions_config();
+        assert_eq!(extensions.e2ee.enabled, Some(true));
+        assert_eq!(extensions.to_device.enabled, Some(true));
+
+        Ok(())
+    }
 }

crates/matrix-sdk/src/sliding_sync/README.md

@@ -192,9 +192,9 @@ any implementation as they please. Handling of the data of the e2ee,
 to-device and typing-extensions takes place transparently within the SDK.
 
 By default [`SlidingSync`][] doesn't activate _any_ extensions to save on
-bandwidth, but we generally recommend to use the [`with_common_extensions`
-when building sliding sync](`SlidingSyncBuilder::with_common_extensions`) to
-active e2ee, to-device-messages and account-data-extensions.
+bandwidth, but we generally recommend to use the `with_XXX_extensions` family
+of methods when building sliding sync to enable e2ee, to-device-messages and
+account-data-extensions.
 
 ## Timeline events
 
@@ -419,7 +419,13 @@ let active_list_name = "active-list".to_owned();
 let sliding_sync_builder = client
     .sliding_sync("main-sync")?
     .sliding_sync_proxy(Url::parse("http://sliding-sync.example.org")?) // our proxy server
-    .with_common_extensions(); // we want the e2ee and to-device enabled, please
+    .with_account_data_extension(
+        assign!(v4::AccountDataConfig::default(), { enabled: Some(true) }),
+    ) // we enable the account-data extension
+    .with_e2ee_extension(assign!(v4::E2EEConfig::default(), { enabled: Some(true) })) // and the e2ee extension
+    .with_to_device_extension(
+        assign!(v4::ToDeviceConfig::default(), { enabled: Some(true) }),
+    ); // and the to-device extension
 
 let full_sync_list = SlidingSyncList::builder(&full_sync_list_name)
     .sync_mode(SlidingSyncMode::Growing { batch_size: 50, maximum_number_of_rooms_to_fetch: Some(500) }) // sync up by growing the window

crates/matrix-sdk/src/sliding_sync/builder.rs

@@ -98,37 +98,6 @@ impl SlidingSyncBuilder {
         Ok(self.add_list(list))
     }
 
-    /// Activate e2ee, to-device-message and account data extensions if not yet
-    /// configured.
-    ///
-    /// Will leave any extension configuration found untouched, so the order
-    /// does not matter.
-    pub fn with_common_extensions(mut self) -> Self {
-        {
-            let cfg = self.extensions.get_or_insert_with(Default::default);
-            if cfg.to_device.enabled.is_none() {
-                cfg.to_device.enabled = Some(true);
-            }
-
-            if cfg.e2ee.enabled.is_none() {
-                cfg.e2ee.enabled = Some(true);
-            }
-
-            if cfg.account_data.enabled.is_none() {
-                cfg.account_data.enabled = Some(true);
-            }
-
-            // TODO: Re-enable once a `lists` and `rooms` will support `*`. See
-            // https://github.com/matrix-org/matrix-rust-sdk/issues/2037 for more info.
-            /*
-            if cfg.receipts.enabled.is_none() {
-                cfg.receipts.enabled = Some(true);
-            }
-            */
-        }
-        self
-    }
-
     /// Activate e2ee, to-device-message, account data, typing and receipt
     /// extensions if not yet configured.
     ///

crates/matrix-sdk/src/sliding_sync/mod.rs

@@ -700,6 +700,16 @@ impl SlidingSync {
     pub async fn force_cache_to_storage(&self, to_device_token: Option<String>) -> Result<()> {
         self.cache_to_storage(to_device_token).await
     }
+
+    /// Read the static extension configuration for this Sliding Sync.
+    ///
+    /// Note: this is not the next content of the sticky parameters, but rightly
+    /// the static configuration that was set during creation of this
+    /// Sliding Sync.
+    pub fn extensions_config(&self) -> ExtensionsConfig {
+        let sticky = self.inner.sticky.read().unwrap();
+        sticky.data().extensions.clone()
+    }
 }
 
 #[derive(Debug)]

testing/sliding-sync-integration-test/src/lib.rs

@@ -14,8 +14,7 @@ async fn setup(
     let client = get_client_for_user(name, use_sqlite_store).await?;
     let sliding_sync_builder = client
         .sliding_sync("test-slidingsync")?
-        .sliding_sync_proxy(sliding_sync_proxy_url.parse()?)
-        .with_common_extensions();
+        .sliding_sync_proxy(sliding_sync_proxy_url.parse()?);
     Ok((client, sliding_sync_builder))
 }