From 0bebec08cd89039c32bd9b9e73d80d573b6bf0b3 Mon Sep 17 00:00:00 2001
From: Paul Buetow <paul@buetow.org>
Date: Fri, 27 Mar 2026 13:30:14 +0200
Subject: sr: fix Raft replay leader election

---
 src/main/java/protocols/VSAbstractProtocol.java    | 31 ++++++++++++++++++++--
 .../protocols/implementations/VSRaftProtocol.java  | 14 ++++++++++
 2 files changed, 43 insertions(+), 2 deletions(-)

(limited to 'src/main/java/protocols')

diff --git a/src/main/java/protocols/VSAbstractProtocol.java b/src/main/java/protocols/VSAbstractProtocol.java
index da12d31..ee0d6c2 100644
--- a/src/main/java/protocols/VSAbstractProtocol.java
+++ b/src/main/java/protocols/VSAbstractProtocol.java
@@ -180,8 +180,8 @@ abstract public class VSAbstractProtocol extends VSAbstractEvent {
      * This method:
      * <ul>
      *   <li>Filters out messages for other protocols</li>
-     *   <li>Ensures server/client initialization</li>
-     *   <li>Delegates to onServerRecv() or onClientRecv() based on context</li>
+     *   <li>Routes messages to the active role(s) without double-delivering
+     *       to dual-role peers</li>
      * </ul>
      *
      * @param message the received message
@@ -192,6 +192,21 @@ abstract public class VSAbstractProtocol extends VSAbstractEvent {
         if (isIncorrectProtocol(message))
             return;
 
+        if (isServer && isClient) {
+            if (message.isServerMessage()) {
+                currentContextIsServer(false);
+                if (!isClientInitialized)
+                    onInit();
+                onClientRecv(message);
+            } else {
+                currentContextIsServer(true);
+                if (!isServerInitialized)
+                    onInit();
+                onServerRecv(message);
+            }
+            return;
+        }
+
         if (isServer) {
             currentContextIsServer(true);
             if (!isServerInitialized)
@@ -226,6 +241,18 @@ abstract public class VSAbstractProtocol extends VSAbstractEvent {
         if (isIncorrectProtocol(message))
             return false;
 
+        return isRelevantMessageForContext(message);
+    }
+
+    /**
+     * Checks whether a message is relevant for this protocol instance.
+     * Subclasses can relax or specialize the default server/client routing
+     * rules while keeping the protocol-name filter intact.
+     *
+     * @param message the message to check
+     * @return true if the message should be processed by this protocol instance
+     */
+    protected boolean isRelevantMessageForContext(VSMessage message) {
         if (message.isServerMessage()) {
             if (!isClient)
                 return false;
diff --git a/src/main/java/protocols/implementations/VSRaftProtocol.java b/src/main/java/protocols/implementations/VSRaftProtocol.java
index c75628d..bad893c 100644
--- a/src/main/java/protocols/implementations/VSRaftProtocol.java
+++ b/src/main/java/protocols/implementations/VSRaftProtocol.java
@@ -103,6 +103,11 @@ public class VSRaftProtocol extends VSAbstractProtocol {
         handleMessage(recvMessage);
     }
 
+    @Override
+    protected boolean isRelevantMessageForContext(VSMessage message) {
+        return isServer() || isClient();
+    }
+
     /* (non-Javadoc)
      * @see protocols.VSAbstractProtocol#onServerSchedule()
      */
@@ -366,7 +371,10 @@ public class VSRaftProtocol extends VSAbstractProtocol {
         heartbeatAck.setInteger("term", currentTerm);
         heartbeatAck.setInteger("pid", process.getProcessID());
         heartbeatAck.setInteger("targetPid", messageLeaderId);
+        boolean previousContextIsServer = currentContextIsServer();
+        currentContextIsServer(true);
         sendMessage(heartbeatAck);
+        currentContextIsServer(previousContextIsServer);
     }
 
     /**
@@ -417,7 +425,10 @@ public class VSRaftProtocol extends VSAbstractProtocol {
         voteResponse.setInteger("pid", process.getProcessID());
         voteResponse.setBoolean("voteGranted", voteGranted);
         voteResponse.setInteger("targetPid", candidateId);
+        boolean previousContextIsServer = currentContextIsServer();
+        currentContextIsServer(true);
         sendMessage(voteResponse);
+        currentContextIsServer(previousContextIsServer);
     }
 
     /**
@@ -487,7 +498,10 @@ public class VSRaftProtocol extends VSAbstractProtocol {
         appendAck.setInteger("pid", process.getProcessID());
         appendAck.setInteger("logIndex", messageLogIndex);
         appendAck.setInteger("targetPid", messageLeaderId);
+        boolean previousContextIsServer = currentContextIsServer();
+        currentContextIsServer(true);
         sendMessage(appendAck);
+        currentContextIsServer(previousContextIsServer);
     }
 
     /**
-- 
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