swarm/shed: add UseMockStore field to IndexItem

swarm/shed/index.go

@@ -37,6 +37,9 @@ type IndexItem struct {
 	Data            []byte
 	AccessTimestamp int64
 	StoreTimestamp  int64
+	// UseMockStore is a pointer to identify
+	// an unset state of the field in Join function.
+	UseMockStore *bool
 }
 
 // Merge is a helper method to construct a new
@@ -55,6 +58,9 @@ func (i IndexItem) Merge(i2 IndexItem) (new IndexItem) {
 	if i.StoreTimestamp == 0 {
 		i.StoreTimestamp = i2.StoreTimestamp
 	}
+	if i.UseMockStore == nil {
+		i.UseMockStore = i2.UseMockStore
+	}
 	return i
 }