From 128bd13a092d2c80e26c1eb91c68bd48e6e753af Mon Sep 17 00:00:00 2001
From: v3xro <175618876+v3xro@users.noreply.github.com>
Date: Wed, 11 Mar 2026 16:12:13 +0000
Subject: [PATCH] Fix #717 by not caching the _internalRef when calling .TryGet
 on the ActorRegistry

---
 src/Akka.Hosting.Tests/RequiredActorSpecs.cs | 33 ++++++++++++++++++++
 src/Akka.Hosting/ActorRegistry.cs            |  4 +--
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/src/Akka.Hosting.Tests/RequiredActorSpecs.cs b/src/Akka.Hosting.Tests/RequiredActorSpecs.cs
index c52a9dd2..3f99e314 100644
--- a/src/Akka.Hosting.Tests/RequiredActorSpecs.cs
+++ b/src/Akka.Hosting.Tests/RequiredActorSpecs.cs
@@ -138,4 +138,37 @@ public async Task ShouldNotCacheNobodyAfterWhenWaitedForRegistration()
         // assert
         cachedActorRef.Should().NotBeOfType<Nobody>();
     }
+    
+    [Fact]
+    public async Task ShouldNotCacheNobodyBeforeRegistrationWithSyncActorRef()
+    {
+        // arrange
+        using var host = new HostBuilder()
+            .ConfigureServices(services =>
+            {
+                services.AddAkka("MySys", (builder, _) =>
+                {
+                    builder.WithActors((system, registry) =>
+                    {
+                        var actor = system.ActorOf(Props.Create(() => new MyActorType()), "myactor");
+                        registry.Register<MyActorType>(actor);
+                    });
+                });
+            })
+            .Build();
+
+        var myRequiredActor = host.Services.GetRequiredService<IRequiredActor<MyActorType>>();
+
+        Action shouldThrow = () => _ = myRequiredActor.ActorRef;
+
+        shouldThrow.Should().Throw<MissingActorRegistryEntryException>();
+
+        await host.StartAsync();
+
+        // act
+        var cachedActorRef = await myRequiredActor.GetAsync();
+
+        // assert
+        cachedActorRef.Should().NotBeOfType<Nobody>();
+    }
 }
\ No newline at end of file
diff --git a/src/Akka.Hosting/ActorRegistry.cs b/src/Akka.Hosting/ActorRegistry.cs
index 017eebc2..62870a29 100644
--- a/src/Akka.Hosting/ActorRegistry.cs
+++ b/src/Akka.Hosting/ActorRegistry.cs
@@ -62,9 +62,9 @@ public IActorRef ActorRef
                     return _internalRef;
 
                 // attempt 2 - synchronously check the registry (fast path)
-                if (_registry.TryGet<TActor>(out _internalRef))
+                if (_registry.TryGet<TActor>(out var internalRef))
                 {
-                    return _internalRef;
+                    return _internalRef = internalRef;
                 }