fix(core/supervisor): remove faulty optimization leading to deadlock

elfo-core/src/object.rs

@@ -147,13 +147,11 @@ pub(crate) trait GroupHandle: Send + Sync + 'static {
 /// Possible sequences of calls:
 /// * `done()`, if handled by a supervisor
 /// * `empty()`, if no relevant actors in a group
-/// * `visit_last()`, if only one relevant actor in a group
-/// * `visit()`, `visit()`, .., `visit_last()`
+/// * `visit()`, otherwise
 pub trait GroupVisitor {
     fn done(&mut self);
     fn empty(&mut self, envelope: Envelope);
-    fn visit(&mut self, object: &ObjectArc, envelope: &Envelope);
-    fn visit_last(&mut self, object: &ObjectArc, envelope: Envelope);
+    fn visit(&mut self, object: &ObjectArc, envelope: Envelope);
 }
 
 // === SendGroupVisitor ===
@@ -266,12 +264,7 @@ impl GroupVisitor for SendGroupVisitor<'_> {
         self.extra = Some(envelope);
     }
 
-    fn visit(&mut self, object: &ObjectArc, envelope: &Envelope) {
-        let envelope = self.extra.take().unwrap_or_else(|| envelope.duplicate());
-        self.try_send(object, envelope);
-    }
-
-    fn visit_last(&mut self, object: &ObjectArc, envelope: Envelope) {
+    fn visit(&mut self, object: &ObjectArc, envelope: Envelope) {
         self.try_send(object, envelope);
     }
 }
@@ -328,12 +321,7 @@ impl GroupVisitor for TrySendGroupVisitor {
         self.extra = Some(envelope);
     }
 
-    fn visit(&mut self, object: &ObjectArc, envelope: &Envelope) {
-        let envelope = self.extra.take().unwrap_or_else(|| envelope.duplicate());
-        self.try_send(object, envelope);
-    }
-
-    fn visit_last(&mut self, object: &ObjectArc, envelope: Envelope) {
+    fn visit(&mut self, object: &ObjectArc, envelope: Envelope) {
         self.try_send(object, envelope);
     }
 }

elfo-core/src/supervisor.rs

@@ -16,7 +16,7 @@ use crate::{
     actor::{Actor, ActorMeta, ActorStatus},
     config::{AnyConfig, Config, SystemConfig},
     context::Context,
-    envelope::Envelope,
+    envelope::{Envelope, EnvelopeOwned},
     exec::{Exec, ExecResult},
     group::{RestartMode, RestartPolicy, TerminationPolicy},
     message::Request,
@@ -218,11 +218,11 @@ where
 
         match outcome {
             Outcome::Unicast(key) => match get_or_spawn!(self, key) {
-                Some(object) => visitor.visit_last(&object, envelope),
+                Some(object) => visitor.visit(&object, envelope),
                 None => visitor.empty(envelope),
             },
             Outcome::GentleUnicast(key) => match self.objects.get(&key) {
-                Some(object) => visitor.visit_last(&object, envelope),
+                Some(object) => visitor.visit(&object, envelope),
                 None => visitor.empty(envelope),
             },
             Outcome::Multicast(list) => {
@@ -251,14 +251,12 @@ where
             return visitor.empty(envelope);
         }
 
-        loop {
-            let object = iter.next().unwrap();
-            if iter.peek().is_none() {
-                return visitor.visit_last(&object, envelope);
-            } else {
-                visitor.visit(&object, &envelope);
-            }
+        for item in iter {
+            visitor.visit(&item, envelope.duplicate());
         }
+
+        let (_, token) = envelope.unpack_request();
+        token.forget();
     }
 
     fn spawn(self: &Arc<Self>, key: R::Key, mut backoff: Backoff) -> Option<ObjectArc> {

elfo-network/src/worker/mod.rs

@@ -585,13 +585,7 @@ impl SocketReader {
                 // TODO: maybe emit some metric?
             }
 
-            fn visit(&mut self, object: &ObjectArc, envelope: &Envelope) {
-                let envelope = envelope.duplicate();
-                self.this
-                    .do_handle_message(self.flows, object, envelope, true);
-            }
-
-            fn visit_last(&mut self, object: &ObjectArc, envelope: Envelope) {
+            fn visit(&mut self, object: &ObjectArc, envelope: Envelope) {
                 self.this
                     .do_handle_message(self.flows, object, envelope, true);
             }