Fix trailing comma issues in teloxide::handler!

src/dispatching/dialogue/mod.rs

@@ -190,11 +190,11 @@ where
 /// (This next handler can be an endpoint or a more complex one.) The payload
 /// format depend on the form of `MyVariant`:
 ///
-///  - For `State::MyVariant(param)`, the payload is `param`.
+///  - For `State::MyVariant(param)` and `State::MyVariant { param }`, the
-///  - For `State::MyVariant(param1, ..., paramN)`, the payload is `(param1,
+///    payload is `param`.
-///    ..., paramN)` (where `N` > 1).
+///  - For `State::MyVariant(param1, ..., paramN)` and `State::MyVariant {
-///  - For `State::MyVariant { param1, ..., paramN }`, the payload is `(param1,
+///    param1, ..., paramN }`, the payload is `(param1, ..., paramN)` (where `N`
-///    ..., paramN)`.
+///    > 1).
 ///
 /// ## Dependency requirements
 ///
@@ -216,6 +216,12 @@ macro_rules! handler {
             _ => None,
         })
     };
+    ($($variant:ident)::+ {$param:ident}) => {
+        $crate::dptree::filter_map(|state| match state {
+            $($variant)::+{$param} => Some($param),
+            _ => None,
+        })
+    };
     ($($variant:ident)::+ {$($param:ident),+ $(,)?}) => {
         $crate::dptree::filter_map(|state| match state {
             $($variant)::+ { $($param),+ } => Some(($($param),+ ,)),
@@ -259,6 +265,18 @@ mod tests {
         assert!(matches!(h.dispatch(dptree::deps![State::Other]).await, ControlFlow::Continue(_)));
     }
 
+    #[tokio::test]
+    async fn handler_single_fn_variant_trailing_comma() {
+        let input = State::B(42);
+        let h = handler![State::B(x,)].endpoint(|(x,): (i32,)| async move {
+            assert_eq!(x, 42);
+            123
+        });
+
+        assert_eq!(h.dispatch(dptree::deps![input]).await, ControlFlow::Break(123));
+        assert!(matches!(h.dispatch(dptree::deps![State::Other]).await, ControlFlow::Continue(_)));
+    }
+
     #[tokio::test]
     async fn handler_fn_variant() {
         let input = State::C(42, "abc");
@@ -275,7 +293,20 @@ mod tests {
     #[tokio::test]
     async fn handler_single_struct_variant() {
         let input = State::D { foo: 42 };
-        let h = handler![State::D { foo }].endpoint(|(x,): (i32,)| async move {
+        let h = handler![State::D { foo }].endpoint(|x: i32| async move {
+            assert_eq!(x, 42);
+            123
+        });
+
+        assert_eq!(h.dispatch(dptree::deps![input]).await, ControlFlow::Break(123));
+        assert!(matches!(h.dispatch(dptree::deps![State::Other]).await, ControlFlow::Continue(_)));
+    }
+
+    #[tokio::test]
+    async fn handler_single_struct_variant_trailing_comma() {
+        let input = State::D { foo: 42 };
+        #[rustfmt::skip] // rustfmt removes the trailing comma from `State::D { foo, }`, but it plays a vital role in this test.
+        let h = handler![State::D { foo, }].endpoint(|(x,): (i32,)| async move {
             assert_eq!(x, 42);
             123
         });