# beacon_chain # Copyright (c) 2018-2022 Status Research & Development GmbH # Licensed and distributed under either of # * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT). # * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0). # at your option. This file may not be copied, modified, or distributed except according to those terms. when (NimMajor, NimMinor) < (1, 4): {.push raises: [Defect].} else: {.push raises: [].} # import ../interpreter # included to be able to use "suite" func setup_votes(): tuple[fork_choice: ForkChoiceBackend, ops: seq[Operation]] = var balances = @[Gwei(1), Gwei(1)] let GenesisRoot = fakeHash(0) # Initialize the fork choice context # We start with epoch 0 fully finalized to avoid epoch 0 special cases. result.fork_choice = ForkChoiceBackend.init( FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1)))) # ---------------------------------- # Head should be genesis result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))), justified_state_balances: balances, expected_head: GenesisRoot) # Add block 2 # # 0 # / # 2 result.ops.add Operation( kind: ProcessBlock, root: fakeHash(2), parent_root: GenesisRoot, blk_checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1)))) # Head should be 2 # # 0 # / # 2 <- head result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))), justified_state_balances: balances, expected_head: fakeHash(2)) # Add block 1 as a fork # # 0 # / \ # 2 1 result.ops.add Operation( kind: ProcessBlock, root: fakeHash(1), parent_root: GenesisRoot, blk_checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1)))) # Head is still 2 due to tiebreaker as fakeHash(2) (0xD8...) > fakeHash(1) (0x7C...) # # 0 # / \ # head-> 2 1 result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))), justified_state_balances: balances, expected_head: fakeHash(2)) # Add a vote to block 1 # # 0 # / \ # 2 1 <- +vote result.ops.add Operation( kind: ProcessAttestation, validator_index: ValidatorIndex(0), block_root: fakeHash(1), target_epoch: Epoch(2)) # Head is now 1 as 1 has an extra vote # # 0 # / \ # 2 1 <- head result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))), justified_state_balances: balances, expected_head: fakeHash(1)) # Add a vote to block 2 # # 0 # / \ # +vote-> 2 1 result.ops.add Operation( kind: ProcessAttestation, validator_index: ValidatorIndex(1), block_root: fakeHash(2), target_epoch: Epoch(2)) # Head is back to 2 due to tiebreaker as fakeHash(2) (0xD8...) > fakeHash(1) (0x7C...) # # 0 # / \ # head-> 2 1 result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))), justified_state_balances: balances, expected_head: fakeHash(2)) # Add block 3 as on chain 1 # # 0 # / \ # 2 1 # | # 3 result.ops.add Operation( kind: ProcessBlock, root: fakeHash(3), parent_root: fakeHash(1), blk_checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1)))) # Head is still 2 # # 0 # / \ # head-> 2 1 result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))), justified_state_balances: balances, expected_head: fakeHash(2) ) # Move validator #0 vote from 1 to 3 # # 0 # / \ # 2 1 <- -vote # | # 3 <- +vote result.ops.add Operation( kind: ProcessAttestation, validator_index: ValidatorIndex(0), block_root: fakeHash(3), target_epoch: Epoch(3)) # Head is still 2 # # 0 # / \ # head-> 2 1 result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))), justified_state_balances: balances, expected_head: fakeHash(2)) # Move validator #1 vote from 2 to 1 (this is an equivocation, but fork choice doesn't # care) # # 0 # / \ # -vote-> 2 1 <- +vote # | # 3 result.ops.add Operation( kind: ProcessAttestation, validator_index: ValidatorIndex(1), block_root: fakeHash(1), target_epoch: Epoch(3)) # Head is now 3 # # 0 # / \ # 2 1 # | # 3 <- head result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))), justified_state_balances: balances, expected_head: fakeHash(3)) # Add block 4 on chain 1-3 # # 0 # / \ # 2 1 # | # 3 # | # 4 result.ops.add Operation( kind: ProcessBlock, root: fakeHash(4), parent_root: fakeHash(3), blk_checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1)))) # Head is now 4 # # 0 # / \ # 2 1 # | # 3 # | # 4 <- head result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))), justified_state_balances: balances, expected_head: fakeHash(4)) # Add block 5, which has a justified epoch of 2. # # 0 # / \ # 2 1 # | # 3 # | # 4 # / # 5 <- justified epoch = 2 result.ops.add Operation( kind: ProcessBlock, root: fakeHash(5), parent_root: fakeHash(4), blk_checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2)))) # Ensure that 5 is filtered out and the head stays at 4. # # 0 # / \ # 2 1 # | # 3 # | # 4 <- head # / # 5 result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))), justified_state_balances: balances, expected_head: fakeHash(4)) # Add block 6, which has a justified epoch of 0. # # 0 # / \ # 2 1 # | # 3 # | # 4 # / \ # 5 6 <- justified epoch = 0 result.ops.add Operation( kind: ProcessBlock, root: fakeHash(6), parent_root: fakeHash(4), blk_checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1)))) # Move both votes to 5. # # 0 # / \ # 2 1 # | # 3 # | # 4 # / \ # +2 vote-> 5 6 result.ops.add Operation( kind: ProcessAttestation, validator_index: ValidatorIndex(0), block_root: fakeHash(5), target_epoch: Epoch(4)) result.ops.add Operation( kind: ProcessAttestation, validator_index: ValidatorIndex(1), block_root: fakeHash(5), target_epoch: Epoch(4)) # Add blocks 7, 8 and 9. Adding these blocks helps test the `best_descendant` # functionality. # # 0 # / \ # 2 1 # | # 3 # | # 4 # / \ # 5 6 # | # 7 # | # 8 # / # 9 result.ops.add Operation( kind: ProcessBlock, root: fakeHash(7), parent_root: fakeHash(5), blk_checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1)))) result.ops.add Operation( kind: ProcessBlock, root: fakeHash(8), parent_root: fakeHash(7), blk_checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1)))) # Finalizes 5 result.ops.add Operation( kind: ProcessBlock, root: fakeHash(9), parent_root: fakeHash(8), blk_checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2)))) # Ensure that 6 is the head, even though 5 has all the votes. This is testing to ensure # that 5 is filtered out due to a differing justified epoch. # # 0 # / \ # 2 1 # | # 3 # | # 4 # / \ # 5 6 <- head # | # 7 # | # 8 # / # 9 result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: GenesisRoot, epoch: Epoch(1)), finalized: Checkpoint(root: GenesisRoot, epoch: Epoch(1))), justified_state_balances: balances, expected_head: fakeHash(6)) # Change fork-choice justified epoch to 1, and the start block to 5 and ensure that 9 is # the head. # # << Change justified epoch to 1 >> # # 0 # / \ # 2 1 # | # 3 # | # 4 # / \ # 5 6 # | # 7 # | # 8 # / # head-> 9 result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))), justified_state_balances: balances, expected_head: fakeHash(9)) # Update votes to block 9 # 0 # / \ # 2 1 # | # 3 # | # 4 # / \ # 5 6 # | # 7 # | # 8 # / # 9 <- +2 votes result.ops.add Operation( kind: ProcessAttestation, validator_index: ValidatorIndex(0), block_root: fakeHash(9), target_epoch: Epoch(5)) result.ops.add Operation( kind: ProcessAttestation, validator_index: ValidatorIndex(1), block_root: fakeHash(9), target_epoch: Epoch(5)) # Head should still be 9 result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))), justified_state_balances: balances, expected_head: fakeHash(9)) # Add block 10 (also finalizes 5) # 0 # / \ # 2 1 # | # 3 # | # 4 # / \ # 5 6 # | # 7 # | # 8 # / \ # 9 10 result.ops.add Operation( kind: ProcessBlock, root: fakeHash(10), parent_root: fakeHash(8), blk_checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2)))) # Head should still be 9 result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))), justified_state_balances: balances, expected_head: fakeHash(9)) # Introduce 2 new validators balances = @[Gwei(1), Gwei(1), Gwei(1), Gwei(1)] # Have them vote for block 10 # 0 # / \ # 2 1 # | # 3 # | # 4 # / \ # 5 6 # | # 7 # | # 8 # / \ # 9 10 <- +2 votes result.ops.add Operation( kind: ProcessAttestation, validator_index: ValidatorIndex(2), block_root: fakeHash(10), target_epoch: Epoch(5)) result.ops.add Operation( kind: ProcessAttestation, validator_index: ValidatorIndex(3), block_root: fakeHash(10), target_epoch: Epoch(5)) # Check that the head is now 10. # # 0 # / \ # 2 1 # | # 3 # | # 4 # / \ # 5 6 # | # 7 # | # 8 # / \ # 9 10 <- head result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))), justified_state_balances: balances, expected_head: fakeHash(10)) # Set the last 2 validators balances to 0 balances = @[Gwei(1), Gwei(1), Gwei(0), Gwei(0)] # head should be 9 again # . # | # 8 # / \ # head -> 9 10 result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))), justified_state_balances: balances, expected_head: fakeHash(9)) # Set the last 2 validators balances back to 1 balances = @[Gwei(1), Gwei(1), Gwei(1), Gwei(1)] # head should be 10 again # . # | # 8 # / \ # 9 10 <- head result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))), justified_state_balances: balances, expected_head: fakeHash(10)) # Remove the validators balances = @[Gwei(1), Gwei(1)] # head should be 9 again # . # | # 8 # / \ # head -> 9 10 result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))), justified_state_balances: balances, expected_head: fakeHash(9)) # Ensure that pruning does prune. # # # 0 # / \ # 2 1 # | # 3 # | # 4 # -------pruned here ------ # 5 6 # | # 7 # | # 8 # / \ # 9 10 # Note: 5 and 6 become orphans # - 5 is the new root # - 6 is a discarded chain result.ops.add Operation( kind: Prune, finalized_root: fakeHash(5), expected_len: 6) # Prune shouldn't have changed the head result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))), justified_state_balances: balances, expected_head: fakeHash(9)) # Add block 11 # # 5 6 # | # 7 # | # 8 # / \ # 9 10 # | # 11 result.ops.add Operation( kind: ProcessBlock, root: fakeHash(11), parent_root: fakeHash(9), blk_checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2)))) # Head is now 11 result.ops.add Operation( kind: FindHead, checkpoints: FinalityCheckpoints( justified: Checkpoint(root: fakeHash(5), epoch: Epoch(2)), finalized: Checkpoint(root: fakeHash(5), epoch: Epoch(2))), justified_state_balances: balances, expected_head: fakeHash(11)) proc test_votes() = test "fork_choice - testing with votes": # for i in 0 ..< 12: # echo " block (", i, ") hash: ", fakeHash(i) # echo " ------------------------------------------------------" var (ctx, ops) = setup_votes() ctx.run(ops) test_votes()