Legacy Chain Check

[oxarbitrage]

Solution

Check Finalized Transaction network_upgrade field

V5 transactions have a network_upgrade field. If Zebra has followed a legacy chain, the network_upgrade field will be different to the calculated network_upgrade for that height.

In StateService::new, immediately after the new state is created:

• get a block iterator using new_service.any_ancestor_blocks(new_service.best_tip().1)
  • if the state is empty, and the best_tip() is None, skip the legacy chain check
• call a function that does the following checks on each block in the iterator:
  • if the block height is less than the NU5 activation height, or there is no NU5 activation height, return Ok(())
  • if you've checked 100 blocks, return an error
    • this check finds pre-NU5 legacy chains, because they don't have V5 transactions with network upgrade fields
  • if Block.check_transaction_network_upgrade (Move the Transaction network upgrade check to zebra-chain #2343) returns an error, return an error
  • if there is at least one transaction with a network_upgrade, and Block.check_transaction_network_upgrade returns success, return Ok(())

Panic and Log User Action

If the finalized tip doesn't pass validation:

• panic
• suggest that the user deletes the database and retries a full sync
• give them the exact database path (Add a path method to the FinalizedState #2344)

Testing

Unit Tests

Test that the legacy chain function works:

If the block height is less than the NU5 activation height, or there is no NU5 activation height, return Ok(())

• test fake v5 blocks that are less than the NU5 activation height
  

  zebra/zebra-chain/src/transaction/tests/vectors.rs

  Lines 235 to 242 in 2291abc

  	let mut fake_block = original_block.clone();
  	fake_block.transactions = fake_block
  	.transactions
  	.iter()
  	.map(AsRef::as_ref)
  	.map(|t| arbitrary::transaction_to_fake_v5(t, network, Height(*height)))
  	.map(Into::into)
  	.collect();

• proptest a block vector containing at least 100 blocks, starting less than 100 blocks past the NU5 activation height
  • some blocks must be lower than the NU5 activation height
  • the transactions need to all be V4, use the transaction version override from Add property test strategies for V5 transactions #2347

If you've checked 100 blocks, return an error:

• proptest a block vector containing at least 100 blocks, starting 100 blocks or more past the NU5 activation height
  • the transactions need to all be V4, use the transaction version override from Add property test strategies for V5 transactions #2347

If Block.check_transaction_network_upgrade returns an error, return that error:

• proptest a block vector starting 100 blocks or more past the NU5 activation height
  • these transactions need to be V5 and some need invalid network_upgrade fields, use the transaction version override from Add property test strategies for V5 transactions #2347
  • to make sure there is an error, use at least 50 blocks

If there is at least one transaction with a network_upgrade, and Block.check_transaction_network_upgrade returns success, return Ok(())

• proptest a block vector containing blocks at the NU5 activation height or higher
  • in some tests, some blocks should be lower than the NU5 activation height
  • the transactions need to be V5 and have valid network_upgrade fields, use the transaction version override and valid network upgrade overrides from Add property test strategies for V5 transactions #2347

Success Cached State Test

Check that the legacy chain check passes in the existing cached state tests:

• search the log output to make sure that the legacy chain check runs and passes
  • add a log at info level when starting the check
  • add a log at info level when the check passes

This is part of a split of #1820