May Progress:
I’ve finished implementing the AcceptBlock and ConnectBlock integration logic, meaning that when a mimblewimble block is received, it will be fully validated, added to the chain, and the UTXO set will be updated. This ended up requiring a lot more rework than I hoped, since the approach I originally took on the mimblewimble side for adding, validating, and removing blocks didn’t line up well with the existing code’s approach to handling the UTXO set using “views” and “caches” (See “Data Access Layer and Caching” here: Bitcoin Core 0.11 (ch 2): Data Storage - Bitcoin Wiki).
The logical next step was to work on DisconnectBlock, which will remove a block from the chain in the case of chain reorgs. However, I chose instead to start working on the mempool, with the hopes that we can soon start mining Mimblewimble blocks. Being able to mine valid mw blocks will allow us to test the end-to-end flow of including mw transactions in a block, validating those blocks, removing the transactions from the mempool, adding the blocks to the chain, updating the UTXO set, and flushing everything to disk. There’s a lot that could go wrong there, so the sooner we can get everything working together, the smoother the rest of development should go.
This is all subject to change, but for now, here’s the plan between now and the end of Summer testnet launch:
June: Wrap up mempool logic, and start mining valid chains with mw extension blocks, making sure all pieces work well together.
July: Initial block download. The way initial block download is handled in mimblewimble is quite a bit different than how litecoin does it. In LTC, every single block from the genesis block is downloaded and validated in order. With mimblewimble, we don’t need the whole history, but instead only parts of each transaction, and all of the unspent outputs. I’ll need to find a way to make those two very different syncing approaches work smoothly together.
August: DisconnectBlock logic (for chain reorgs).
September: Testnet activation logic and launch of the first mimblewimble testnet. Then start fixing everything I broke 