Remove Option wrapper around directory filters

ruma-client-api/src/r0/directory/get_public_rooms_filtered.rs

@@ -35,8 +35,8 @@ ruma_api! {
         pub since: Option<&'a str>,
 
         /// Filter to apply to the results.
-        #[serde(skip_serializing_if = "Option::is_none")]
-        pub filter: Option<Filter<'a>>,
+        #[serde(default, skip_serializing_if = "Filter::is_empty")]
+        pub filter: Filter<'a>,
 
         /// Network to fetch the public room lists from.
         #[serde(flatten, skip_serializing_if = "ruma_serde::is_default")]

ruma-common/src/directory.rs

@@ -98,6 +98,7 @@ impl From<PublicRoomsChunkInit> for PublicRoomsChunk {
 /// A filter for public rooms lists
 #[derive(Clone, Debug, Default, Outgoing, Serialize)]
 #[cfg_attr(not(feature = "unstable-exhaustive-types"), non_exhaustive)]
+#[incoming_derive(Default)]
 pub struct Filter<'a> {
     /// A string to search for in the room metadata, e.g. name, topic, canonical alias etc.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -109,6 +110,11 @@ impl Filter<'_> {
     pub fn new() -> Self {
         Default::default()
     }
+
+    /// Returns `true` if the filter is empty.
+    pub fn is_empty(&self) -> bool {
+        self.generic_search_term.is_none()
+    }
 }
 
 /// Information about which networks/protocols from application services on the

ruma-federation-api/src/directory/get_public_rooms_filtered/v1.rs

@@ -27,8 +27,8 @@ ruma_api! {
         pub since: Option<&'a str>,
 
         /// Filter to apply to the results.
-        #[serde(skip_serializing_if = "Option::is_none")]
-        pub filter: Option<Filter<'a>>,
+        #[serde(default, skip_serializing_if = "Filter::is_empty")]
+        pub filter: Filter<'a>,
 
         /// Network to fetch the public room lists from.
         #[serde(flatten, skip_serializing_if = "ruma_serde::is_default")]