client-api: Always serialize the search results field.

It was skipped when empty, so a search response whose final page has no
results omitted the field entirely. Clients expect it to always be present.

Signed-off-by: Jason Volk <jason@zemos.net>

Author: jevolk

crates/ruma-client-api/CHANGELOG.md

@@ -28,6 +28,8 @@ Bug fixes:
 
 - Fix `sync_events::v5::Request::set_presence` being read from / serialized to
   the JSON body instead of the query string.
+- Serialize the `results` field of `search_events` responses even when empty,
+  so clients can rely on the key being present.
 
 [MSC4383]: https://github.com/matrix-org/matrix-spec-proposals/pull/4383
 

crates/ruma-client-api/src/search/search_events.rs

@@ -369,7 +369,9 @@ pub mod v3 {
         pub next_batch: Option<String>,
 
         /// List of results in the requested order.
-        #[serde(default, skip_serializing_if = "Vec::is_empty")]
+        ///
+        /// Serialized even when empty so that clients can rely on the field being present.
+        #[serde(default)]
         pub results: Vec<SearchResult>,
 
         /// The current state for every room in the results.