sr: fix Raft replay leader election

5 files changed, 89 insertions, 5 deletions

diff --git a/saved-simulations/raft.dat b/saved-simulations/raft.dat
index 5738148..262809a 100644
--- a/saved-simulations/raft.dat
+++ b/saved-simulations/raft.dat
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);
     }
 
     /**
diff --git a/src/main/java/simulator/builder/SimulationFactory.java b/src/main/java/simulator/builder/SimulationFactory.java
index 48ec638..165e42d 100644
--- a/src/main/java/simulator/builder/SimulationFactory.java
+++ b/src/main/java/simulator/builder/SimulationFactory.java
@@ -96,10 +96,12 @@ public class SimulationFactory {
             .activateClientsAt(100, 1)
             .activateClientsAt(1700, 2)
             // Bias process 1 toward a fast, clean post-crash election while
-            // keeping process 2's timeout comfortably behind it.
-            .setProtocolLong(1, "electionTimeout", 4000)
+            // keeping process 2's timeout comfortably behind it. The shorter
+            // timeout also keeps the headless replay active long enough to
+            // reach the first post-crash election deterministically.
+            .setProtocolLong(1, "electionTimeout", 2500)
             .setProtocolLong(1, "electionJitter", 0)
-            .setProtocolLong(2, "electionTimeout", 9000)
+            .setProtocolLong(2, "electionTimeout", 12000)
             .setProtocolLong(2, "electionJitter", 0)
             .addCrashEvent(0, 3500);
     }
diff --git a/src/test/java/protocols/implementations/VSRaftProtocolTest.java b/src/test/java/protocols/implementations/VSRaftProtocolTest.java
index 40dfd10..802c80f 100644
--- a/src/test/java/protocols/implementations/VSRaftProtocolTest.java
+++ b/src/test/java/protocols/implementations/VSRaftProtocolTest.java
@@ -390,6 +390,33 @@ class VSRaftProtocolTest {
     }
 
     @Test
+    void testDualRoleVoteRequestIsHandledOnce() throws Exception {
+        protocol.currentContextIsServer(false);
+        protocol.isClient(true);
+        protocol.isServer(true);
+        protocol.onInit();
+        clearInvocations(mockProcess, mockTaskManager);
+        when(mockProcess.getTime()).thenReturn(200L, 200L);
+
+        VSMessage voteRequest = new VSMessage();
+        setMessageProtocolClassname(voteRequest, VSRaftProtocol.class.getName());
+        setMessageServerFlag(voteRequest, true);
+        voteRequest.setString("type", "voteRequest");
+        voteRequest.setInteger("term", 2);
+        voteRequest.setInteger("candidateId", 11);
+
+        ArgumentCaptor<VSMessage> messageCaptor =
+            ArgumentCaptor.forClass(VSMessage.class);
+
+        protocol.onMessageRecvStart(voteRequest);
+
+        verify(mockProcess).sendMessage(messageCaptor.capture());
+        assertEquals("voteResponse", messageCaptor.getValue().getString("type"));
+        assertEquals(2, messageCaptor.getValue().getInteger("term"));
+        assertTrue(messageCaptor.getValue().getBoolean("voteGranted"));
+    }
+
+    @Test
     void testClientReceiveHeartbeatBecomesFollowerResetsTimeoutAndSendsAck()
     throws Exception {
         protocol.currentContextIsServer(false);
@@ -764,6 +791,20 @@ class VSRaftProtocolTest {
         field.setBoolean(protocol, value);
     }
 
+    private void setMessageProtocolClassname(VSMessage message, String classname)
+    throws Exception {
+        Field field = VSMessage.class.getDeclaredField("protocolClassname");
+        field.setAccessible(true);
+        field.set(message, classname);
+    }
+
+    private void setMessageServerFlag(VSMessage message, boolean isServerMessage)
+    throws Exception {
+        Field field = VSMessage.class.getDeclaredField("isServerMessage");
+        field.setAccessible(true);
+        field.setBoolean(message, isServerMessage);
+    }
+
     private int getIntField(String fieldName) throws Exception {
         Field field = VSRaftProtocol.class.getDeclaredField(fieldName);
         field.setAccessible(true);