On Wed, Dec 9, 2015 at 4:44 AM, Ryan Butler <rryanani...@gmail.com> wrote: >>I agree, but nothing I have advocated creates significant technical >>debt. It is also a bad engineering practice to combine functional >>changes (especially ones with poorly understood system wide >>consequences and low user autonomy) with structural tidying. > > I don't think I would classify placing things in consensus critical code > when it doesn't need to be as "structural tidying". Gavin said "pile on" > which you took as implying "a lot", he can correct me, but I believe he > meant "add to".
Nothing being discussed would move something from consensus critical code to not consensus critical. What was being discussed was the location of the witness commitment; which is consensus critical regardless of where it is placed. Should it be placed in an available location which is compatible with the existing network, or should the block hashing data structure immediately be changed in an incompatible way to accommodate it in order to satisfy an ascetic sense of purity and to make fraud proofs somewhat smaller? I argue that the size difference in the fraud proofs is not interesting, the disruption to the network in an incompatible upgrade is interesting; and that if it really were desirable reorganization to move the commitment point could be done as part of a separate change that changes only the location of things (and/or other trivial adjustments); and that proceeding int this fashion would minimize disruption and risk... by making the incompatible changes that will force network wide software updates be as small and as simple as possible. >> (especially ones with poorly understood system wide consequences and low >> user autonomy) > > This implies there you have no confidence in the unit tests and functional > testing around Bitcoin and should not be a reason to avoid refactoring. > It's more a reason to increase testing so that you will have confidence when > you refactor. I am speaking from our engineering experience in a public, world-wide, multi-vendor, multi-version, inter-operable, distributed system which is constantly changing and in production contains private code, unknown and assorted hardware, mixtures of versions, unreliable networks, undisclosed usage patterns, and more sources of complex behavior than can be counted-- including complex economic incentives and malicious participants. Even if we knew the complete spectrum of possible states for the system the combinatioric explosion makes complete testing infeasible. Though testing is essential one cannot "unit test" away all the risks related to deploying a new behavior in the network. _______________________________________________ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
