fix last commit breakage

db/btree.cpp

@@ -309,12 +309,12 @@ namespace mongo {
      *  does not bother returning that value.
      */
     template< class V >
-    void BucketBasics<V>::popBack(DiskLoc& recLoc, const Key *&key) {
+    void BucketBasics<V>::popBack(DiskLoc& recLoc, Key &key) {
         massert( 10282 ,  "n==0 in btree popBack()", this->n > 0 );
         assert( k(this->n-1).isUsed() ); // no unused skipping in this function at this point - btreebuilder doesn't require that
         KeyNode kn = keyNode(this->n-1);
         recLoc = kn.recordLoc;
-        key = &kn.key;
+        key.assign(kn.key);
         int keysize = kn.key.dataSize();
 
         massert( 10283 , "rchild not null in btree popBack()", this->nextChild.isNull());

db/btree.h

@@ -429,7 +429,7 @@ namespace mongo {
          *  - The last key of the bucket is removed, and its key and recLoc are
          *    returned.  As mentioned above, the key points to unallocated memory.
          */
-        void popBack(DiskLoc& recLoc, const Key *&key);
+        void popBack(DiskLoc& recLoc, Key &key);
 
         /**
          * Preconditions:

db/btreebuilder.cpp

@@ -114,19 +114,19 @@ namespace mongo {
                 }
 
                 BtreeBucket<V> *x = xloc.btreemod<V>();
-                const Key *k;
+                Key k;
                 DiskLoc r;
                 x->popBack(r,k);
                 bool keepX = ( x->n != 0 );
                 DiskLoc keepLoc = keepX ? xloc : x->nextChild;
 
-                if ( ! up->_pushBack(r, *k, ordering, keepLoc) ) {
+                if ( ! up->_pushBack(r, k, ordering, keepLoc) ) {
                     // current bucket full
                     DiskLoc n = BtreeBucket<V>::addBucket(idx);
                     up->setTempNext(n);
                     upLoc = n;
                     up = upLoc.btreemod<V>();
-                    up->pushBack(r, *k, ordering, keepLoc);
+                    up->pushBack(r, k, ordering, keepLoc);
                 }
 
                 DiskLoc nextLoc = x->tempNext(); // get next in chain at current level

db/key.h

@@ -28,7 +28,7 @@ namespace mongo {
 
         KeyV1 is the new implementation.
     */
-    class KeyBson { 
+    class KeyBson /* "KeyV0" */ { 
     public:
         KeyBson() { }
         explicit KeyBson(const char *keyData) : _o(keyData) { }
@@ -41,6 +41,7 @@ namespace mongo {
         BSONElement _firstElement() const { return _o.firstElement(); }
         bool isCompactFormat() const { return false; }
         bool woEqual(const KeyBson& r) const;
+        void assign(const KeyBson& rhs) { *this = rhs; }
     private:
         BSONObj _o;
     };
@@ -59,6 +60,11 @@ namespace mongo {
             dassert( _keyData > (const unsigned char *) 1 );
         }
 
+        // explicit version of operator= to be safe
+        void assign(const KeyV1& rhs) { 
+            _keyData = rhs._keyData;
+        }
+
         /** @param keyData can be a buffer containing data in either BSON format, OR in KeyV1 format. 
                    when BSON, we are just a wrapper
         */