Merge pull request #399 from onflow/fxamacker/fix-get-child-reference…

…s-to-handle-storage-id-in-element-in-stable-cadence

Fix migration filter for old unreferenced slabs (non-inlining feature branch)

storage.go

@@ -1071,40 +1071,60 @@ func (s *PersistentSlabStorage) FixLoadedBrokenReferences(needToFix func(old Val
 			return false
 		}
 
-		var isMetaDataSlab bool
-
 		switch slab.(type) {
-		case *ArrayMetaDataSlab, *MapMetaDataSlab:
-			isMetaDataSlab = true
-		}
+		case *ArrayMetaDataSlab, *MapMetaDataSlab: // metadata slabs
+			var foundBrokenRef bool
 
-		var foundBrokenRef bool
-		for _, childStorable := range slab.ChildStorables() {
+			for _, childStorable := range slab.ChildStorables() {
 
-			storageIDStorable, ok := childStorable.(StorageIDStorable)
-			if !ok {
-				continue
-			}
+				if slabIDStorable, ok := childStorable.(StorageIDStorable); ok {
 
-			childID := StorageID(storageIDStorable)
+					childID := StorageID(slabIDStorable)
 
-			// Track parent-child relationship of root slabs and non-root slabs.
-			if isMetaDataSlab {
-				parentOf[childID] = id
-			}
+					// Track parent-child relationship of root slabs and non-root slabs.
+					parentOf[childID] = id
 
-			if s.existIfLoaded(childID) {
-				continue
+					if !s.existIfLoaded(childID) {
+						foundBrokenRef = true
+					}
+
+					// Continue with remaining child storables to track parent-child relationship.
+				}
 			}
 
-			foundBrokenRef = true
+			return foundBrokenRef
+
+		default: // data slabs
+			childStorables := slab.ChildStorables()
+
+			for len(childStorables) > 0 {
+
+				var nextChildStorables []Storable
+
+				for _, childStorable := range childStorables {
+
+					if slabIDStorable, ok := childStorable.(StorageIDStorable); ok {
 
-			if !isMetaDataSlab {
-				return true
+						if !s.existIfLoaded(StorageID(slabIDStorable)) {
+							return true
+						}
+
+						continue
+					}
+
+					// Append child storables of this childStorable to
+					// handle nested StorageIDStorable, such as Cadence SomeValue.
+					nextChildStorables = append(
+						nextChildStorables,
+						childStorable.ChildStorables()...,
+					)
+				}
+
+				childStorables = nextChildStorables
 			}
-		}
 
-		return foundBrokenRef
+			return false
+		}
 	}
 
 	var brokenStorageIDs []StorageID
@@ -1273,6 +1293,11 @@ func (s *PersistentSlabStorage) getAllChildReferences(slab Slab) (
 
 			storageIDStorable, ok := childStorable.(StorageIDStorable)
 			if !ok {
+				nextChildStorables = append(
+					nextChildStorables,
+					childStorable.ChildStorables()...,
+				)
+
 				continue
 			}