The DynamicVerifier verifies a SignedHeader by first updating to a FullCommit for SignedHeader.Height - 1. Then it should have FullCommit.NextValidatorSet.Hash() == SignedHeader.ValidatorsHash and can verify the signatures.

It verifies this using a BaseVerifier once it has all the data.

Then, to update to a FullCommit for height SignedHeader.Height, it needs the validator set for SignedHeader.Height + 1.

The current behaviour is as follow:

• if it can't get this validator set, return no error
• if it can get this validator set, check that it matches the SignedHeader.NextValidatorsHash, and if not, return an error
• if it can get this val set, it matches, and it verifies, then save the new full commit and return no error

First, why do we ignore the error if we can't get the validator set? If it's because Tendermint doesn't expose the next validator set for the latest block over /validators, then maybe we can fix that.

Second, it seems we're doing a full verification of the commit twice: once with the BaseVerifier, and once with the FullCommit:

and

It seems the latter verification is mostly redundant. The only part that's needed from it is checking the NextValidatorSet matches up.

We should investigate and clean this up if it's indeed true.

Related: #3173