From 31e882841940f8c362b392a883eec86634efb7d9 Mon Sep 17 00:00:00 2001
From: Timon Passlick <timon.passlick@student.kit.edu>
Date: Thu, 25 Jun 2026 00:29:55 +0200
Subject: [PATCH] fix state inconsistency in Orleans Chirper account (issue
 #7124)

---
 orleans/Chirper/Chirper.Grains/ChirperAccount.cs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/orleans/Chirper/Chirper.Grains/ChirperAccount.cs b/orleans/Chirper/Chirper.Grains/ChirperAccount.cs
index 5d72315b932..b58fcc76b5b 100644
--- a/orleans/Chirper/Chirper.Grains/ChirperAccount.cs
+++ b/orleans/Chirper/Chirper.Grains/ChirperAccount.cs
@@ -3,10 +3,11 @@
 using Microsoft.Extensions.Logging;
 using Orleans.Concurrency;
 using Orleans.Runtime;
+using Orleans.Serialization.Invocation;
 
 namespace Chirper.Grains;
 
-[Reentrant]
+[MayInterleave(nameof(WontFollowAndUnfollowSimultaneously))]
 public sealed class ChirperAccount : Grain, IChirperAccount
 {
     /// <summary>
@@ -48,6 +49,9 @@ public ChirperAccount(
     private static string GrainType => nameof(ChirperAccount);
     private string GrainKey => this.GetPrimaryKeyString();
 
+    public static bool WontFollowAndUnfollowSimultaneously(IInvokable request) =>
+        request.GetMethodName() is not (nameof(FollowUserIdAsync) or nameof(UnfollowUserIdAsync));
+
     public override Task OnActivateAsync(CancellationToken _)
     {
         _logger.LogInformation("{GrainType} {GrainKey} activated.", GrainType, GrainKey);