SSZ hash: error in Container hashing function

[zilm13]

What's wrong

PR #595 that changed usage of regular hash to merkle_hash for Containers adds an error, because container fields are not of homogeneous length if you follow the spec. Let me point it:

1. Container

Recursively tree hash the values in the container in the same order as the fields, and Merkle hash the results.

return merkle_hash([hash_tree_root_internal(getattr(x, field)) for field in value.fields])

2. The below hash_tree_root_internal algorithm is defined recursively in the case of lists and containers, and it outputs a value equal to or less than 32 bytes in size.

 # Merkle tree hash of a list of **homogenous**, non-empty items
def merkle_hash(lst):

Proposal

Use hash_tree_root instead of hash_tree_root_internal in Container function, so fields are homogenous.

[JustinDrake]

The SSZ spec was rewritten here, and no longer has a hash_tree_root_internal. Feedback welcome there :)

[zilm13]

@JustinDrake yeah I saw it, but it looks too far from final. Or did you decide to remove Python code at all? It helped a lot. So new spec doesn't contain this error?

[JustinDrake]

I believe the re-write does not have this error.

[zilm13]

Cool, so I close this and trying to get into rewrite