Once Bitcoin forks, will it become a copycat coin? Gavin Andresen talks with Charlie Lee

Yesterday, Charlie Lee, the founder of Litecoin and the director of engineering at the digital currency company Coinbase, posted 13 tweets about Bitcoin Unlimited (BU), which sparked heated discussions in the Bitcoin community. Charlie Lee believes that even after Bitcoin forks, the BU chain will be abandoned by users, and the BU coin will eventually become a copycat coin. Gavin Andresen, who clearly supports Bitcoin Unlimited, responded: Miners are not fools.

Charlie Lee said:

1. Many people ask me, if there is a Bitcoin fork, what will GDAX choose? Which one will be the genuine Bitcoin? This is a million dollar question!

2. Coinbase/GDAX still hasn’t given an answer because we don’t know the answer either. But if this were to happen, I would give the following advice.
3. Bitcoin Unlimited (BU) is a compatible hard fork upgrade for Bitcoin. This means that the BU chain will accept all blocks of the 1Mb blockchain.
4. The current Bitcoin Core (BC) chain will not accept any blocks larger than 1Mb in its chain.
5. It is extremely dangerous for GDAX or any exchange to support the BU chain, it is unstable because it can be destroyed at any time.
6. This means that at any time, the BC chain will always be longer than the BU chain (in PoW mode);
7. All existing BU transactions will be discarded in the BC chain. GDAX exchange will be responsible for everything!
8. If the market makes the BC chain more valuable, then the computing power will be transferred to this chain, making it longer, but how can this actually happen?
9. Therefore, I would never recommend GDAX to support the BU code.
10. The only solution to this problem is for the BU team to release code to lock it in a block after the fork occurs.
11. This is because this block locking function is needed after the fork occurs, only in this way can GDAX start supporting BU at some time after the fork.
12. This means that when the fork occurs, the BTC traded on the GDAX exchange must come from the BC chain. The BU chain is a copycat coin that just forked the BC chain.
13. But if GDAX really supports the BU chain, it will also list Bitcoin Unlimited as another symbol, such as BTU.

Later, Gavin Andresen also joined the discussion on this topic.

Gavin: Why would miners switch from the BU chain back to the BC chain after the fork? This doesn’t make sense unless the miners are fools.

Charlie Lee: When the fork is settled, users will make the BC chain more valuable. By then, the BC chain will be more profitable and it will attract more miners.

Gavin: Maybe I'm missing something, can you write some scenarios that make sense where a 1MB chain with minority hashrate suddenly gains more value?

Charlie Lee: User value: BU was originally due to the acquisition of additional computing power. After the fork, developers and merchants decided to stick with the BC chain, so that the value of the BC chain would increase.

Charlie Lee: As I said, it's a naive idea to assume that things will happen as we think they will. We have made a mistake with ETC.

Gavin: Miners are not stupid, they will not generate blocks larger than >1MB if users/exchanges/etc say no.

A heated debate between the BC community and the BU community

The debate between Charlie Lee and Gavin also attracted more discussions, among which core supporter WhalePanda wrote a blog post titled "How Bitcoin Unlimited (BTU coin) will be cleared."

He wrote in the article:

“Let’s think about this: you are a large miner and you can influence the hashrate and difficulty of a coin. What is the most profitable thing to do?

At the beginning, you will invest most of your mining machines into mining BTU coins. After the first difficulty adjustment of BTC, you will arrange some of your mining machines to mine BTC, but not too much, and then gradually increase the investment in BTC (the difficulty is lower, so you can actually get more coins than before).

You will continue to do this until at some point you find yourself with all your miners moving from BTU to BTC, and then the BTC chain will catch up to the BTU chain, eventually wiping out the BTU chain…

”

R/btc user mallocdotc commented: Charlie Lee assumed that the blockchain would split, assuming that the chain with the lower proof of work would be BU.

That's good, it shows they are scared. They are trying to continue to make people think core is in control, but they realize the block size debate is at the end of emergency consensus. Don't be surprised if they take out their EC code and try to push a SWSF (user activated soft fork).

The real battle is over Segwit and node control. They will still push for SWSF (User Activated Soft Fork), but we cannot allow this dangerous Segwit code to be implemented. Flextrans is proven to be more resilient, efficient and secure.

BU developer Andrew Stone replied: Interestingly, there is already a solution. This is a hidden remote procedure call protocol (RPC) called invalidateblock , which was already present in the "Nakamoto" client when BU was launched. Basically, if the long blockchain starts to be caught up by the short blockchain, anyone who wants to stick to the shorter blockchain with a minority computing power can "invalidateblock" the 1MB chain.

Which side do you think makes more sense?