RATIS-2051 Fix Sonar bugs for Ratis

ratis-common/src/main/java/org/apache/ratis/util/LeakDetector.java

@@ -84,6 +84,7 @@ private void run() {
           tracker.reportLeak();
         }
       } catch (InterruptedException e) {
+        Thread.currentThread().interrupt();
         LOG.warn("Thread interrupted, exiting.", e);
         break;
       }

ratis-common/src/main/java/org/apache/ratis/util/PeerProxyMap.java

@@ -45,6 +45,7 @@ public class PeerProxyMap<PROXY extends Closeable> implements RaftPeer.Add, Clos
   /** Peer and its proxy. */
   private class PeerAndProxy {
     private final RaftPeer peer;
+    @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
     private volatile PROXY proxy = null;
     private final LifeCycle lifeCycle;
 

ratis-common/src/main/java/org/apache/ratis/util/Preconditions.java

@@ -78,6 +78,11 @@ static void assertTrue(boolean value, Supplier<Object> message) {
     }
   }
 
+  static void assertSame(int expected, int computed, String name) {
+    assertTrue(expected == computed,
+        () -> name + ": expected == " + expected + " but computed == " + computed);
+  }
+
   static void assertSame(long expected, long computed, String name) {
     assertTrue(expected == computed,
         () -> name + ": expected == " + expected + " but computed == " + computed);

ratis-grpc/src/main/java/org/apache/ratis/grpc/server/GrpcLogAppender.java

@@ -156,6 +156,7 @@ synchronized int process(Event event) {
   private final TimeDuration logMessageBatchDuration;
   private final int maxOutstandingInstallSnapshots;
   private final TimeoutExecutor scheduler = TimeoutExecutor.getInstance();
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile StreamObservers appendLogRequestObserver;
   private final boolean useSeparateHBChannel;
 

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

@@ -41,8 +41,10 @@ public class ConfigurationManager {
    * The current raft configuration. If configurations is not empty, should be
    * the last entry of the map. Otherwise is initialConf.
    */
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile RaftConfigurationImpl currentConf;
   /** Cache the peer corresponding to {@link #id}. */
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile RaftPeer currentPeer;
 
   ConfigurationManager(RaftPeerId id, RaftConfigurationImpl initialConf) {

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

@@ -59,6 +59,7 @@ int update(AtomicInteger outstanding) {
   private final RaftServerImpl server;
 
   private final Timestamp creationTime = Timestamp.currentTime();
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile Timestamp lastRpcTime = creationTime;
   private volatile boolean isRunning = true;
   private final AtomicInteger outstandingOp = new AtomicInteger();

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

@@ -92,7 +92,7 @@ private Timestamp getMaxTimestampWithMajorityAck(List<FollowerInfo> followers) {
       return Timestamp.currentTime();
     }
 
-    final int mid = followers.size() / 2;
+    final long mid = followers.size() / 2;
     return followers.stream()
         .map(FollowerInfo::getLastRespondedAppendEntriesSendTime)
         .sorted()

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

@@ -269,7 +269,7 @@ static boolean isSameConf(CurrentOldFollowerInfos cached, RaftConfigurationImpl
 
   static class FollowerInfoMap {
     private final Map<RaftPeerId, FollowerInfo> map = new ConcurrentHashMap<>();
-
+    @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
     private volatile CurrentOldFollowerInfos followerInfos;
 
     void put(RaftPeerId id, FollowerInfo info) {
@@ -333,6 +333,7 @@ boolean isApplied() {
   private final RaftServerImpl server;
   private final RaftLog raftLog;
   private final long currentTerm;
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile ConfigurationStagingState stagingState;
 
   private final FollowerInfoMap followerInfoMap = new FollowerInfoMap();

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

@@ -148,6 +148,7 @@ boolean isStable() {
     return oldConf == null;
   }
 
+  @SuppressWarnings({"squid:S6466"}) // Suppress  ArrayIndexOutOfBoundsException warning
   boolean containsInConf(RaftPeerId peerId, RaftPeerRole... roles) {
     if (roles == null || roles.length == 0) {
       return conf.contains(peerId);

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

@@ -87,6 +87,7 @@ class ServerState {
   /**
    * Candidate that this peer granted vote for in current term (or null if none)
    */
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile RaftPeerId votedFor;
 
   /**
@@ -171,6 +172,7 @@ private RaftLog initRaftLog(LongSupplier getSnapshotIndexFromStateMachine, RaftP
     }
   }
 
+  @SuppressWarnings({"squid:S2095"}) // Suppress closeable  warning
   private static RaftLog initRaftLog(RaftGroupMemberId memberId, RaftServerImpl server, RaftStorage storage,
       Consumer<LogEntryProto> logConsumer, LongSupplier getSnapshotIndexFromStateMachine,
       RaftProperties prop) throws IOException {

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

@@ -199,6 +199,7 @@ public void run() {
         }
       } catch (Throwable t) {
         if (t instanceof InterruptedException && state == State.STOP) {
+          Thread.currentThread().interrupt();
           LOG.info("{} was interrupted.  Exiting ...", this);
         } else {
           state = State.EXCEPTION;

ratis-server/src/main/java/org/apache/ratis/server/metrics/LeaderElectionMetrics.java

@@ -51,6 +51,7 @@ public final class LeaderElectionMetrics extends RatisMetrics {
 
   private final Timekeeper electionTime = getRegistry().timer(LEADER_ELECTION_TIME_TAKEN);
 
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile Timestamp lastElectionTime;
 
   private LeaderElectionMetrics(RaftGroupMemberId serverId, LongSupplier getLastLeaderElapsedTimeMs) {

ratis-server/src/main/java/org/apache/ratis/server/raftlog/segmented/LogSegment.java

@@ -294,10 +294,10 @@ File getFile() {
   private volatile boolean isOpen;
   private long totalFileSize = SegmentedRaftLogFormat.getHeaderLength();
   /** Segment start index, inclusive. */
-  private long startIndex;
+  private final long startIndex;
   /** Segment end index, inclusive. */
   private volatile long endIndex;
-  private RaftStorage storage;
+  private final RaftStorage storage;
   private final SizeInBytes maxOpSize;
   private final LogEntryLoader cacheLoader;
   /** later replace it with a metric */

ratis-server/src/main/java/org/apache/ratis/server/raftlog/segmented/SegmentedRaftLog.java

@@ -211,6 +211,7 @@ public TransactionContext getTransactionContext(LogEntryProto entry, boolean cre
   private final boolean stateMachineCachingEnabled;
   private final SegmentedRaftLogMetrics metrics;
 
+  @SuppressWarnings({"squid:S2095"}) // Suppress closeable  warning
   private SegmentedRaftLog(Builder b) {
     super(b.memberId, b.snapshotIndexSupplier, b.properties);
     this.metrics = new SegmentedRaftLogMetrics(b.memberId);

ratis-server/src/main/java/org/apache/ratis/server/raftlog/segmented/SegmentedRaftLogCache.java

@@ -396,6 +396,7 @@ public String toString() {
   }
 
   private final String name;
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile LogSegment openSegment;
   private final LogSegmentList closedSegments;
   private final RaftStorage storage;

ratis-server/src/main/java/org/apache/ratis/server/raftlog/segmented/SegmentedRaftLogWorker.java

@@ -143,6 +143,7 @@ synchronized void updateIndex(long i) {
   private volatile boolean running = true;
   private final ExecutorService workerThreadExecutor;
   private final RaftStorage storage;
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile SegmentedRaftLogOutputStream out;
   private final Runnable submitUpdateCommitEvent;
   private final StateMachine stateMachine;

ratis-server/src/main/java/org/apache/ratis/server/storage/RaftStorageDirectoryImpl.java

@@ -210,6 +210,7 @@ void lock() throws IOException {
    * <code>null</code> if storage is already locked.
    * @throws IOException if locking fails.
    */
+  @SuppressWarnings({"squid:S2095"}) // Suppress closeable  warning
   private FileLock tryLock(File lockF) throws IOException {
     boolean deletionHookAdded = false;
     if (!lockF.exists()) {

ratis-server/src/main/java/org/apache/ratis/server/storage/SnapshotManager.java

@@ -77,6 +77,7 @@ public class SnapshotManager {
         new File(dir.get().getRoot(), c.getFilename()).toPath()).toString();
   }
 
+  @SuppressWarnings({"squid:S2095"}) // Suppress closeable  warning
   private FileChannel open(FileChunkProto chunk, File tmpSnapshotFile) throws IOException {
     final FileChannel out;
     final boolean exists = tmpSnapshotFile.exists();

ratis-server/src/main/java/org/apache/ratis/statemachine/impl/BaseStateMachine.java

@@ -50,6 +50,7 @@
 public class BaseStateMachine implements StateMachine, StateMachine.DataApi,
     StateMachine.EventApi, StateMachine.LeaderEventApi, StateMachine.FollowerEventApi {
   private final CompletableFuture<RaftServer> server = new CompletableFuture<>();
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile RaftGroupId groupId;
   private final LifeCycle lifeCycle = new LifeCycle(JavaUtils.getClassSimpleName(getClass()));
 

ratis-server/src/main/java/org/apache/ratis/statemachine/impl/TransactionContextImpl.java

@@ -49,6 +49,7 @@ public class TransactionContextImpl implements TransactionContext {
   private final RaftClientRequest clientRequest;
 
   /** Exception from the {@link StateMachine} or from the log */
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile Exception exception;
 
   /** Data from the {@link StateMachine} */
@@ -60,6 +61,7 @@ public class TransactionContextImpl implements TransactionContext {
    * {@link StateMachine#startTransaction(RaftClientRequest)} and
    * {@link StateMachine#applyTransaction(TransactionContext)}.
    */
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile Object stateMachineContext;
 
   /**
@@ -70,11 +72,14 @@ public class TransactionContextImpl implements TransactionContext {
   private boolean shouldCommit = true;
 
   /** Committed LogEntry. */
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile LogEntryProto logEntry;
   /** Committed LogEntry copy. */
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile Supplier<LogEntryProto> logEntryCopy;
 
   /** For wrapping {@link #logEntry} in order to release the underlying buffer. */
+  @SuppressWarnings({"squid:S3077"}) // Suppress volatile for generic type
   private volatile ReferenceCountedObject<?> delegatedRef;
 
   private final CompletableFuture<Long> logIndexFuture = new CompletableFuture<>();