Policy lists via UTXO: lists updated before block confirmation.

[lawlawlaw]

This currently applies to the utxolists branch.

In validation.cpp, in ConnectBlock. The policy lists are updated from the transactions in the block before the block is fully validated; ConnectBlock could later return "false" with CValidationState other than "MODE_VALID".

[nkostoulas]

Is this still a problem?

[lawlawlaw]

Potentially, yes. Ideally, the policy lists etc. should be updated just before the "return true". However, this could affect transactions within the same block that depend on policy.

[nkostoulas]

Ok this sounds serious. Affect how do you mean?

[lawlawlaw]

For example, an address is added to the freeze list in a policy transaction. In a later transaction, in the same block, the asset from the frozen address is spent. So in this case the earlier transaction invalidates the later transaction.

[lawlawlaw]

Unless we want policy list changes only to take effect in the next block.

[nkostoulas]

I think this part is fine since policy lists are used for mempool rejection. Still we shouldn't be updating them until the block is fully validated.

[lawlawlaw]

I'll push a fix for this in a moment.
Another possible issue is if e.g. DisconnectBlock is called, the policy lists wont be updated.
This also affects AssetMap and FreezeHistory.

[nkostoulas]

partly resolved. relevant issue open #128