Zero out contents of a newly-created persisted ChronicleHash

src/main/java/net/openhft/chronicle/hash/impl/VanillaChronicleHash.java

@@ -56,6 +56,10 @@ public abstract class VanillaChronicleHash<K, KI, MKI extends MetaBytesInterop<K
     // Version
     public final String dataFileVersion;
 
+    /////////////////////////////////////////////////
+    // If the hash was created in the first place, or read from disk
+    public transient boolean created = false;
+
     /////////////////////////////////////////////////
     // Key Data model
     public final Class<K> kClass;
@@ -110,10 +114,15 @@ public abstract class VanillaChronicleHash<K, KI, MKI extends MetaBytesInterop<K
 
     public transient CompactOffHeapLinearHashTable hashLookup;
 
-    public VanillaChronicleHash(ChronicleMapBuilder<K, ?> builder, boolean replicated) {
+    public VanillaChronicleHash(
+            ChronicleMapBuilder<K, ?> builder, boolean replicated) {
         // Version
         dataFileVersion = BuildVersion.version();
 
+        // Because we are in constructor. If the Hash is not created, deserialization bypasses
+        // the constructor and created = false
+        this.created = true;
+
         @SuppressWarnings("deprecation")
         ChronicleHashBuilderPrivateAPI<K> privateAPI = builder.privateAPI();
 
@@ -205,6 +214,9 @@ public abstract class VanillaChronicleHash<K, KI, MKI extends MetaBytesInterop<K
         //OS.warnOnWindows(sizeInBytes());
         createMappedStoreAndSegments(new MappedStore(file, FileChannel.MapMode.READ_WRITE,
                 sizeInBytes(), BytesMarshallableSerializer.create()));
+        // newly-extended file contents are not guaranteed to be zero
+        if (created)
+            bytes.zeroOut(headerSize, bytes.capacity(), true);
     }
 
     private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {

src/main/java/net/openhft/chronicle/map/ChronicleMapBuilder.java

@@ -1358,7 +1358,8 @@ public final class ChronicleMapBuilder<K, V> implements
             File file, SingleChronicleHashReplication singleHashReplication,
             ReplicationChannel channel) throws IOException {
         for (int i = 0; i < 10; i++) {
-            if (file.exists() && file.length() > 0) {
+            long fileLength = file.length();
+            if (fileLength > 0) {
                 try (FileInputStream fis = new FileInputStream(file);
                      ObjectInputStream ois = new ObjectInputStream(fis)) {
                     Object m;
@@ -1379,6 +1380,12 @@ public final class ChronicleMapBuilder<K, V> implements
                             (VanillaChronicleMap<K, ?, ?, V, ?, ?, ?>) m;
                     map.initTransientsFromBuilder(this);
                     map.headerSize = roundUpMapHeaderSize(fis.getChannel().position());
+                    long sizeInBytes = map.sizeInBytes();
+                    if (sizeInBytes != fileLength) {
+                        throw new IOException("The file " + file + "the map is serialized from " +
+                                "has unexpected length " + fileLength + ", probably corrupted. " +
+                                "Expected length is " + sizeInBytes);
+                    }
                     map.createMappedStoreAndSegments(file);
                     // This is needed to property initialize key and value serialization builders,
                     // which are later used in replication
@@ -1388,7 +1395,7 @@ public final class ChronicleMapBuilder<K, V> implements
                     return establishReplication(map, singleHashReplication, channel);
                 }
             }
-            if (file.createNewFile() || file.length() == 0) {
+            if (file.createNewFile() || fileLength == 0) {
                 break;
             }
             try {

src/main/java/net/openhft/chronicle/map/ReplicatedChronicleMap.java

@@ -208,10 +208,10 @@ public class ReplicatedChronicleMap<K, KI, MKI extends MetaBytesInterop<K, ? sup
     public void onHeaderCreated() {
         long offset = super.mapHeaderInnerSize();
 
-        identifierUpdatedBytes = ms.bytes(offset, LAST_UPDATED_HEADER_SIZE).zeroOut();
+        identifierUpdatedBytes = ms.bytes(offset, LAST_UPDATED_HEADER_SIZE);
         offset += LAST_UPDATED_HEADER_SIZE;
 
-        Bytes modDelBytes = ms.bytes(offset, assignedModIterBitSetSizeInBytes()).zeroOut();
+        Bytes modDelBytes = ms.bytes(offset, assignedModIterBitSetSizeInBytes());
         offset += assignedModIterBitSetSizeInBytes();
         startOfModificationIterators = offset;
         modIterSet = new ATSDirectBitSet(modDelBytes);