Can someone explain, technically, what would happen if a majority of the miners adopted a soft fork (forward-compatible) making some tx invalid and then a miner who didn't fork happened to mine a block containing an invalid tx (but still valid on his fork)?
Basically what I don't understand is that there's a proposal where, apparently, miners can choose which addresses they want to block.
So what if, say, there are 4 groups of miners:
- group 1 considers invalid tx to/from address A (17% of miners)
- group 2 considers invalid tx to/from address B (23% of miners)
- group 3 considers invalid tx to/from address A & B (20% of miners)
- group 4 doesn't want to soft fork or doesn't bother (40% of miners)
Isn't group 4 guaranteed to "win", because group 1, 2 and 3 will each be on their own fork, resulting in four forks? Although should have groups 1,2 and 3 all agreed on the same rules for what was invalid, they'd have 60% of the mining power and hence "won"?
Or is the upcoming proposal going to be the same for everyone, and everybody who wants to fork is going to consider the exact same blocks as invalids?
And the second thing I don't understand: there has to be a block at which the new rule kick in and 50%+1 of the miners have to have updated to the soft fork by then for the (forward-compatible) fork to be succesful right? Yet I don't see any block number at which the new rules would kick in the current soft fork proposal code.
Any technical answer is very welcome (*).