This helps us prepare for a better backport of D3471.
- Group Reviewers
It doesn't looks like this is creating a self consistent API. In fact, you are importing assumption about the whole program (namely, that there is one config) into BlockAssembler, which a very clear and very bad regression.
You have a config here.
You are adding a new config parameter here. What if the don't match? What are the expectations here?