Delete node error

[Vladimir Yudin]

When you try to remove a single node from a branch with a value, an error occurs.

To reproduce:

var Trie = require('merkle-patricia-tree')

trie = new Trie()
var ops = [
   { type: 'put', key: 'do', value: 'verb' }
 , { type: 'put', key: 'dog', value: 'puppy' }
]

trie.batch(ops,
 () => {
  trie.del('dog')
 }
)

Output:

node test_trie.js
/home/local/tmp/node_modules/merkle-patricia-tree/baseTrie.js:631
var branchNodeKey = branchNode.key;
^

TypeError: Cannot read property 'key' of undefined
at processBranchNode (/home/local/tmp/node_modules/merkle-patricia-tree/baseTrie.js:631:40)
at /home/local/tmp/node_modules/merkle-patricia-tree/baseTrie.js:730:19
at /home/local/tmp/node_modules/merkle-patricia-tree/baseTrie.js:212:11
at /home/local/tmp/node_modules/merkle-patricia-tree/util.js:87:7
at /home/local/tmp/node_modules/async/dist/async.js:473:16
at replenish (/home/local/tmp/node_modules/async/dist/async.js:1006:25)
at iterateeCallback (/home/local/tmp/node_modules/async/dist/async.js:995:17)
at /home/local/tmp/node_modules/async/dist/async.js:969:16
at /home/local/tmp/node_modules/merkle-patricia-tree/util.js:83:7
at /home/local/tmp/node_modules/merkle-patricia-tree/baseTrie.js:187:13

The reason is that when nodes in a branch are counted (baseTrie.js:573), the value of the node is taken as a reference to the node.
Next, there is a try to get the node (baseTrie.js:588) and access it (baseTrie.js:490).

[Holger Drewes]

Thanks for reporting, can you open a PR on this?

[Holger Drewes]

(optimally with an additional test case?)

[Vladimir Yudin]

Sorry! But I am writing in C ++, I tried to port the algorithm and came across errors. I ran the node.js to check if I introduced these errors. I just reported them.

[Holger Drewes]

@Lion17 Ok, that's nevertheless valuable, thanks! 👍

[Holger Drewes]

Update: see https://github.com/ethereumjs/merkle-patricia-tree/issues/85 for a path to an updated example to retest this.

[Holger Drewes]

Will close this in favor of #85