Also parse int64 when processing indexes (go-mgo#476)

session.go

@@ -1534,12 +1534,25 @@ func (idxs indexSlice) Swap(i, j int)      { idxs[i], idxs[j] = idxs[j], idxs[i]
 
 func simpleIndexKey(realKey bson.D) (key []string) {
 	for i := range realKey {
+		var vi int
 		field := realKey[i].Name
-		vi, ok := realKey[i].Value.(int)
-		if !ok {
+
+		switch realKey[i].Value.(type) {
+		case int64:
+			vf, _ := realKey[i].Value.(int64)
+			vi = int(vf)
+		case float64:
 			vf, _ := realKey[i].Value.(float64)
 			vi = int(vf)
+		case string:
+			if vs, ok := realKey[i].Value.(string); ok {
+				key = append(key, "$"+vs+":"+field)
+				continue
+			}
+		case int:
+			vi = realKey[i].Value.(int)
 		}
+
 		if vi == 1 {
 			key = append(key, field)
 			continue
@@ -1548,10 +1561,6 @@ func simpleIndexKey(realKey bson.D) (key []string) {
 			key = append(key, "-"+field)
 			continue
 		}
-		if vs, ok := realKey[i].Value.(string); ok {
-			key = append(key, "$"+vs+":"+field)
-			continue
-		}
 		panic("Got unknown index key type for field " + field)
 	}
 	return