Add panic if copy is performed with non-empty stack of snapshots

core/state/multi_tx_snapshot.go

@@ -550,8 +550,6 @@ func (stack *MultiTxSnapshotStack) Size() int {
 
 // Invalidate invalidates the latest snapshot. This is used when state changes are committed to trie.
 func (stack *MultiTxSnapshotStack) Invalidate() {
-	// TODO: if latest snapshot is invalid, then all previous snapshots
-	//   would also be invalidated, need to update logic to reflect that
 	size := len(stack.snapshots)
 	if size == 0 {
 		return
@@ -561,7 +559,6 @@ func (stack *MultiTxSnapshotStack) Invalidate() {
 	head.invalid = true
 	stack.snapshots = stack.snapshots[:0]
 	stack.snapshots = append(stack.snapshots, head)
-	//stack.snapshots[size-1].invalid = true
 }
 
 // UpdatePendingStatus updates the pending status for an address.

core/state/statedb.go

@@ -718,6 +718,11 @@ func (s *StateDB) Copy() *StateDB {
 		hasher:               crypto.NewKeccakState(),
 	}
 	// Initialize new multi-transaction snapshot stack for the copied state
+	// NOTE(wazzymandias): We avoid copying the snapshot stack from the original state
+	//   because it may contain snapshots that are not valid for the copied state.
+	if s.multiTxSnapshotStack.Size() > 0 {
+		panic("cannot copy state with active multi-transaction snapshot stack")
+	}
 	state.multiTxSnapshotStack = NewMultiTxSnapshotStack(state)
 	// Copy the dirty states, logs, and preimages
 	for addr := range s.journal.dirties {