I have built a merkle tree by tree.insert(hashes), and then I want to update the value of a leaf_node and update the value of the node in the path, but don't build a new tree, how can i complish this goal? I didn't find the functions in the TreeT that I can use. And if I want to add a new leaf, I can insert it, and it will automatically modify the tree, but how can I delete a node, and it will automatically modify the tree too. Thanks so much for seeing here, english is not my native language, sorry for not flunent.

Hello! The size returned by the serialised_size() method of the path is inconsistent with the actual serialization size.

int main() {
  merkle::Tree::Hash hash("fa8f44eabb728d4020e7f33d1aa973faaef19de6c06679bccdc5100a3c01f54a");
  merkle::Tree tree;
  tree.insert(hash);
  auto root = tree.root();
  auto path = tree.path(0);

  std::cout << path->serialised_size() << std::endl;
  // output: 32

  std::vector<uint8_t> serialised_path;
  path->serialise(serialised_path);
  std::cout << serialised_path.size() << std::endl;
  // output: 56

  return 0;
}

Hello,

I noticed that the original example provided in the main documentation page of the repo isn't working.

For example, the path method which is present on the tree structure, doesn't return a reference but a pointer... which makes this line in the example wrong:

auto path = tree.path(0);
assert(path.verify(root));

Which should be:

auto path = tree.path(0);
assert(path->verify(root));

But even if we fix this little issue, another come just after (with the VS compiler in my case), which comes from the line

After some research, the problem comes from the hash size passed in parameters, the hash should be of size 32bits, but the provided example only provide a string "message", which is not 32bits, hence making the example crash.

I think this should be explained in the documentation, because it's not obvious that the string should be 32 bits.

Spotted by @fournet:

We need to add bounds checks here, or use .at() instead of operator[].