Automatically merged updates to draft EIP(s) 1344 (#2079)

Hi, I'm a bot! This change was automatically merged because:

 - It only modifies existing Draft or Last Call EIP(s)
 - The PR was approved or written by at least one author of each modified EIP
 - The build is passing

EIPS/eip-1344.md

@@ -28,6 +28,10 @@ Currently, there is no specification for how chain ID is set for a particular ne
 
 In order to mitigate this situation, users of the proposed `CHAINID` opcode **must** ensure that their application can handle a potential update to the value of chain ID during their usage of their application in case this does occur, if required for the continued use of the application. A Trustless Oracle that logs the timestamp when a change is made to chain ID can be implemented either as an application-level feature inside the application contract system, or referenced as a globally standard contract. Failure to provide a mitigation for this scenario could lead to a sudden loss of legitimacy of previously signed off-chain messages, which could be an issue during settlement periods and other longer-term verification events for these types of messages. Not all applications of this opcode may need mitigations to handle this scenario, but developers should provide reasoning on a case-by-case basis.
 
+One example of a scenario where it would not make sense to leverage a global oracle is with the Plasma L2 paradigm. In the Plasma paradigm, an operator or group of operators submit blocks from the L2 network to the base chain (in this case Ethereum) summarizing transactions that have occurred on that chain. The submission of these blocks may not perfectly align with major events on the mainchain, such as a split causing an update of chain ID, which may cause a significant insecurity in the protocol if chain ID is utilized in signing messages. If the operators are not allowed to control the update of chain ID they will not be able to perfectly synchronize the update with their block submissions, and certain past transactions may be rejected because they do not align with the update. This is one example of the unintended consequences of trying to specify too much of the behavior of chain ID during a contentious split, and why having a simple opcode for access is most optimal, versus a more complicated precompile or contract.
+
+This proposed opcode would be the simplest possible way to implement this functionality, and allows developers the flexibility to implement their own global or local handling of chain ID changes, if required.
+
 ## Backwards Compatibility
 This EIP is fully backwards compatible with all chains which implement EIP-155 chain ID domain separator for transaction signing.
 
@@ -40,5 +44,8 @@ TBD
 ## Implementation
 A sample implementation was attempted here: https://github.com/fubuloubu/py-evm/commit/eaab5ffa2164d4cc06ae5c855a49d030965be828
 
+An example implementation of a trustless chain ID oracle was implemented here:
+https://github.com/fubuloubu/chain-id-oracle/blob/master/ChainIdOracle.vy
+
 ## Copyright
 Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).