This PR fixes an error in trie commit. If the trie.root is nil, it can be two possible scenarios:
- The trie was empty, and no change happens
- The trie was non-empty and all nodes are dropped
For the latter one, we should collect the deletions and apply them into database(e.g. in PBSS).
Co-authored-by: rjl493456442 <garyrong0905@gmail.com>
Trie tracer is an auxiliary tool to capture all deleted nodes
which can't be captured by trie.Committer. The deleted nodes
can be removed from the disk later.
Co-authored-by: rjl493456442 <garyrong0905@gmail.com>