server: allow using Resource::post_error without DisplayHandle

Author: i509VCB

wayland-server/src/lib.rs

@@ -73,8 +73,10 @@ pub trait Resource: Sized {
     ) -> Result<Message<ObjectId>, InvalidId>;
 
     #[inline]
-    fn post_error(&self, dh: &DisplayHandle, code: impl Into<u32>, error: impl Into<String>) {
-        dh.post_error(self, code.into(), error.into())
+    fn post_error(&self, code: impl Into<u32>, error: impl Into<String>) {
+        if let Some(dh) = self.handle().upgrade().map(DisplayHandle::from) {
+            dh.post_error(self, code.into(), error.into());
+        }
     }
 
     #[doc(hidden)]

wayland-tests/tests/protocol_errors.rs

@@ -40,7 +40,7 @@ fn client_receive_generic_error() {
             3,
         )
         .unwrap();
-    compositor.post_error(&server.display.handle(), 42u32, "I don't like you!");
+    compositor.post_error(42u32, "I don't like you!");
 
     // the error has not yet reached the client
     assert!(client.conn.protocol_error().is_none());