Fix some bugs.

ratis-server/src/main/java/org/apache/ratis/server/impl/LeaderStateImpl.java

@@ -289,16 +289,19 @@ private List<FollowerInfo> getFollowerInfos(PeerConfiguration peers) {
     }
   }
 
-  /** Leader startup state. */
-  private class StartupState {
-    /** At startup, append the current configuration to the log. */
-    private final long startIndex = appendConfiguration(server.getRaftConf());
-    /** Leader becomes ready when the applied index >= start index. */
-    private final AtomicBoolean isReady = new AtomicBoolean();
-
-    boolean checkReady(long appliedIndex) {
+  /** When Leader startup, append a log entry . */
+  private class StartupLogEntry {
+    /** The log index at leader startup. */
+    private final long startIndex = appendConfiguration(RaftConfigurationImpl.newBuilder()
+        .setConf(server.getRaftConf().getConf())
+        .setLogEntryIndex(raftLog.getNextIndex())
+        .build());
+    /** Is the log entry applied? */
+    private final AtomicBoolean applied = new AtomicBoolean();
+
+    boolean checkStartIndex(long appliedIndex) {
       if (appliedIndex >= startIndex) {
-        isReady.set(true);
+        applied.set(true);
         LOG.info("leader is ready since appliedIndex == {} >= startIndex == {}",
             appliedIndex, startIndex);
         return true;
@@ -307,8 +310,8 @@ boolean checkReady(long appliedIndex) {
       }
     }
 
-    boolean isReady() {
-      return isReady.get() || checkReady(server.getState().getLastAppliedIndex());
+    boolean isApplied() {
+      return applied.get() || checkStartIndex(server.getState().getLastAppliedIndex());
     }
   }
 
@@ -336,7 +339,7 @@ boolean isReady() {
   private final WatchRequests watchRequests;
   private final MessageStreamRequests messageStreamRequests;
 
-  private final MemoizedSupplier<StartupState> startupState = MemoizedSupplier.valueOf(StartupState::new);
+  private final MemoizedSupplier<StartupLogEntry> startupLogEntry = MemoizedSupplier.valueOf(StartupLogEntry::new);
   private final AtomicBoolean isStopped = new AtomicBoolean();
 
   private final int stagingCatchupGap;
@@ -398,20 +401,19 @@ void start() {
     // Also this message can help identify the last committed index and the conf.
     CodeInjectionForTesting.execute(APPEND_PLACEHOLDER,
         server.getId().toString(), null);
-    // Initialize start state
-    startupState.get();
+    // append the startup log entry to RaftLog
+    startupLogEntry.get();
     processor.start();
     senders.forEach(LogAppender::start);
   }
 
-
   boolean isReady() {
-    return startupState.isInitialized() && startupState.get().isReady();
+    return startupLogEntry.isInitialized() && startupLogEntry.get().isApplied();
   }
 
   void checkReady(LogEntryProto entry) {
-    Preconditions.assertTrue(startupState.isInitialized());
-    if (entry.getTerm() == getCurrentTerm() && startupState.get().checkReady(entry.getIndex())) {
+    Preconditions.assertTrue(startupLogEntry.isInitialized());
+    if (entry.getTerm() == getCurrentTerm() && startupLogEntry.get().checkStartIndex(entry.getIndex())) {
       server.getStateMachine().leaderEvent().notifyLeaderReady();
     }
   }
@@ -979,7 +981,7 @@ private void replicateNewConf() {
         .build();
     // stop the LogAppender if the corresponding follower and listener is no longer in the conf
     updateSenders(newConf);
-    appendConfiguration(conf);
+    appendConfiguration(newConf);
     notifySenders();
   }