Index: modules/analysis/icu/src/java/org/apache/lucene/collation/tokenattributes/ICUCollatedTermAttributeImpl.java
===================================================================
--- modules/analysis/icu/src/java/org/apache/lucene/collation/tokenattributes/ICUCollatedTermAttributeImpl.java	(revision 1075830)
+++ modules/analysis/icu/src/java/org/apache/lucene/collation/tokenattributes/ICUCollatedTermAttributeImpl.java	(working copy)
@@ -42,7 +42,8 @@
   @Override
   public int toBytesRef(BytesRef target) {
     collator.getRawCollationKey(toString(), key);
-    target.bytes = key.bytes;
+    target.grow(key.size);
+    System.arraycopy(key.bytes, 0, target.bytes, 0, key.size);
     target.offset = 0;
     target.length = key.size;
     return target.hashCode();
Index: lucene/src/test/org/apache/lucene/index/Test2BTerms.java
===================================================================
--- lucene/src/test/org/apache/lucene/index/Test2BTerms.java	(revision 1075520)
+++ lucene/src/test/org/apache/lucene/index/Test2BTerms.java	(working copy)
@@ -75,9 +75,7 @@
 
     private final static class MyTermAttributeImpl extends AttributeImpl implements TermToBytesRefAttribute {
       public int toBytesRef(BytesRef bs) {
-        bs.bytes = bytes.bytes;
-        bs.offset = bytes.offset;
-        bs.length = bytes.length;
+        bs.copy(bytes);
         return bytes.hashCode();
       }
       @Override
Index: lucene/src/java/org/apache/lucene/analysis/tokenattributes/TermToBytesRefAttribute.java
===================================================================
--- lucene/src/java/org/apache/lucene/analysis/tokenattributes/TermToBytesRefAttribute.java	(revision 1075520)
+++ lucene/src/java/org/apache/lucene/analysis/tokenattributes/TermToBytesRefAttribute.java	(working copy)
@@ -44,6 +44,8 @@
    * Implement this for performance reasons, if your code can calculate
    * the hash on-the-fly. If this is not the case, just return
    * {@code termBytes.hashCode()}.
+   * NOTE: you must make a new copy of the underlying byte[] for each term, as
+   * the consumer owns this byte array.
    */
   public int toBytesRef(BytesRef termBytes);
 }