BEP89
Note: this feature is only available in Testnet after Lagrange Upgrade.
Motivations
5DAX Chain will have some hard forks inevitably in the long run. When different valdiator nodes use different version of 5DAX Chains codebase either unintentionally or as a result of an attack, it may lead to a consensus fork or a chain split. By far the vast majority of changes to the 5DAX Chain codebase have no impact on consensus rules. Note that this type of fork is very different than a codebase fork (usually done by cloning someone else’s repository).
When a change is proposed that affects compatibility with other nodes, a BEP (5DAX Evolution Proposal) is typically required. A brief description of the BEP process along with a list of existing BEPs can be found here.
BEP89 is introduced to enable the chain to display the whole view of validators that on different upcoming forks. Any nodes/validators can decide to upgrade/fork or not accordingly. 5DAX Chain full nodes are able to display the whole view of validators that on different upcoming forks.
Implementatiion
The proposal FORK_HASH takes an "IEEE CRC32 checksum ([4]byte) of the genesis hash + fork blocks numbers that already passed. Validator nodes will fill in Header.Extra with NEXT_FORK_HASH during preparing block header.
The fullnodes will log a warning message if the majority NEXT_FORK_HASH is different from local.
Example log of warning:
t=2021-01-20T21:40:09+0800 lvl=warn msg="there is a possible fork, and your client is not the majority. Please check..." nextForkHash=cd0d163d
t=2021-01-20T21:40:09+0800 lvl=warn msg="there is a possible fork, and your client is not the majority. Please check..." nextForkHash=cd0d163d
t=2021-01-20T21:40:09+0800 lvl=warn msg="there is a possible fork, and your client is not the majority. Please check..." nextForkHash=cd0d163d
t=2021-01-20T21:40:09+0800 lvl=warn msg="there is a possible fork, and your client is not the majority. Please check..." nextForkHash=cd0d163d
t=2021-01-20T21:40:09+0800 lvl=warn msg="there is a possible fork, and your client is not the majority. Please check..." nextForkHash=cd0d163d
t=2021-01-20T21:40:09+0800 lvl=warn msg="there is a possible fork, and your client is not the majority. Please check..." nextForkHash=cd0d163d
t=2021-01-20T21:40:09+0800 lvl=warn msg="there is a possible fork, and your client is not the majority. Please check..." nextForkHash=cd0d163d