Patch to naively synchronize RubyHash to protect direct-addressing data store

synchronize.diff

diff --git a/core/src/main/java/org/jruby/RubyHash.java b/core/src/main/java/org/jruby/RubyHash.java
index 231971b6be..a17a473e0a 100644
--- a/core/src/main/java/org/jruby/RubyHash.java
+++ b/core/src/main/java/org/jruby/RubyHash.java
@@ -697,7 +697,7 @@ public class RubyHash extends RubyObject implements Map {
                 IRubyObject otherKey = entryKey(entries, index);
                 int otherHash = hashes[index];
 
-                if (internalKeyExist(key, hash, otherKey, otherHash)) return bin;
+                if (internalKeyExist(key, hash, otherKey, otherHash, isComparedByIdentity())) return bin;
             }
 
             bin = secondaryBucketIndex(bin, bins.length);
@@ -728,7 +728,7 @@ public class RubyHash extends RubyObject implements Map {
         set(entries, index, null, null);
     }
 
-    private final int internalGetIndexLinearSearch(final int hash, final IRubyObject key) {
+    private synchronized final int internalGetIndexLinearSearch(final int hash, final IRubyObject key) {
         long extents = this.extents;
         int start = START(extents);
         int end = END(extents);
@@ -741,7 +741,7 @@ public class RubyHash extends RubyObject implements Map {
 
             int otherHash = hashes[i];
 
-            if (internalKeyExist(key, hash, otherKey, otherHash)) return i;
+            if (internalKeyExist(key, hash, otherKey, otherHash, isComparedByIdentity())) return i;
         }
         return EMPTY_BIN;
     }
@@ -770,8 +770,8 @@ public class RubyHash extends RubyObject implements Map {
         return internalGetEntry(key);
     }
 
-    private boolean internalKeyExist(IRubyObject key, int hash, IRubyObject otherKey, int otherHash) {
-        return (hash == otherHash && (key == otherKey || (!isComparedByIdentity() && key.eql(otherKey))));
+    private static boolean internalKeyExist(IRubyObject key, int hash, IRubyObject otherKey, int otherHash, boolean identity) {
+        return (hash == otherHash && (key == otherKey || (!identity && key.eql(otherKey))));
     }
 
     // delete implementation
@@ -793,7 +793,7 @@ public class RubyHash extends RubyObject implements Map {
         return internalDelete(hashValue(key), MATCH_ENTRY, key, value);
     }
 
-    private final IRubyObject internalDeleteOpenAddressing(final int hash, final EntryMatchType matchType, final IRubyObject key, final IRubyObject value) {
+    private synchronized final IRubyObject internalDeleteOpenAddressing(final int hash, final EntryMatchType matchType, final IRubyObject key, final IRubyObject value) {
         int[] bins = this.bins;
 
         int bin = bucketIndex(hash, bins.length);
@@ -824,7 +824,7 @@ public class RubyHash extends RubyObject implements Map {
         return null;  // no entry found
     }
 
-    private final IRubyObject internalDeleteLinearSearch(final EntryMatchType matchType, final IRubyObject key, final IRubyObject value) {
+    private synchronized final IRubyObject internalDeleteLinearSearch(final EntryMatchType matchType, final IRubyObject key, final IRubyObject value) {
         long extents = this.extents;
         int start = START(extents);
         int end = END(extents);
@@ -946,7 +946,7 @@ public class RubyHash extends RubyObject implements Map {
         visitLimited(context, visitor, -1, state);
     }
 
-    private <T> void visitLimited(ThreadContext context, VisitorWithState visitor, long size, T state) {
+    private synchronized <T> void visitLimited(ThreadContext context, VisitorWithState visitor, long size, T state) {
         int startGeneration = generation;
         long count = size;
         int index = 0;
@@ -977,7 +977,7 @@ public class RubyHash extends RubyObject implements Map {
         if (count > 0) throw concurrentModification();
     }
 
-    public <T> boolean allSymbols() {
+    public synchronized <T> boolean allSymbols() {
         int startGeneration = generation;
 
         long extents = this.extents;
@@ -1243,7 +1243,7 @@ public class RubyHash extends RubyObject implements Map {
         return this;
     }
 
-    private void rehashOpenAddressing() {
+    private synchronized void rehashOpenAddressing() {
         IRubyObject[] entries = this.entries;
 
         IRubyObject[] newEntries = new IRubyObject[entries.length];
@@ -1274,7 +1274,7 @@ public class RubyHash extends RubyObject implements Map {
                 // cannot be non-EMPTY_BIN and not contain a valid newEntry.
                 IRubyObject otherKey = entryKey(newEntries, index);
                 int otherHash = newHashes[index];
-                if (internalKeyExist(key, hash, otherKey, otherHash)) {
+                if (internalKeyExist(key, hash, otherKey, otherHash, isComparedByIdentity())) {
                     // exists, we do not need to add this key
                     exists = true;
                     break;
@@ -1298,7 +1298,7 @@ public class RubyHash extends RubyObject implements Map {
         this.setExtents(0, size = newIndex);
     }
 
-    private void rehashLinearSearch() {
+    private synchronized void rehashLinearSearch() {
         IRubyObject[] entries = this.entries;
         int[] hashes = this.hashes;
 
@@ -1319,7 +1319,7 @@ public class RubyHash extends RubyObject implements Map {
             for(int j = 0; j < i; j++) {
                 int otherHash = hashes[j];
                 IRubyObject otherKey = entryKey(newEntries, j);
-                if (internalKeyExist(key, newHash, otherKey, otherHash)) {
+                if (internalKeyExist(key, newHash, otherKey, otherHash, isComparedByIdentity())) {
                     exists = true;
                     break;
                 }
@@ -2044,7 +2044,7 @@ public class RubyHash extends RubyObject implements Map {
      *
      */
     @JRubyMethod(name = "shift")
-    public IRubyObject shift(ThreadContext context) {
+    public synchronized IRubyObject shift(ThreadContext context) {
         modify();
 
         long extents = this.extents;
@@ -2417,7 +2417,7 @@ public class RubyHash extends RubyObject implements Map {
     }
 
     @JRubyMethod(name = "compact!")
-    public IRubyObject compact_bang(ThreadContext context) {
+    public synchronized IRubyObject compact_bang(ThreadContext context) {
         boolean changed = false;
         modify();
         iteratorEntry();
@@ -2485,7 +2485,7 @@ public class RubyHash extends RubyObject implements Map {
         return any_p_i(context, block);
     }
 
-    private IRubyObject any_p_i(ThreadContext context, Block block) {
+    private synchronized IRubyObject any_p_i(ThreadContext context, Block block) {
         iteratorEntry();
         try {
             long extents = this.extents;
@@ -2508,7 +2508,7 @@ public class RubyHash extends RubyObject implements Map {
         }
     }
 
-    private IRubyObject any_p_i_fast(ThreadContext context, Block block) {
+    private synchronized IRubyObject any_p_i_fast(ThreadContext context, Block block) {
         iteratorEntry();
         try {
             long extents = this.extents;
@@ -2530,7 +2530,7 @@ public class RubyHash extends RubyObject implements Map {
         }
     }
 
-    private IRubyObject any_p_p(ThreadContext context, IRubyObject pattern) {
+    private synchronized IRubyObject any_p_p(ThreadContext context, IRubyObject pattern) {
         iteratorEntry();
         try {
             long extents = this.extents;