github.com/ethereum-optimism/optimism@v1.7.2/packages/contracts-bedrock/invariant-docs/CrossDomainMessenger.md (about)

     1  # `CrossDomainMessenger` Invariants
     2  
     3  ## A call to `relayMessage` should succeed if at least the minimum gas limit can be supplied to the target context, there is enough gas to complete execution of `relayMessage` after the target context's execution is finished, and the target context did not revert.
     4  **Test:** [`CrossDomainMessenger.t.sol#L143`](../test/invariants/CrossDomainMessenger.t.sol#L143)
     5  
     6  There are two minimum gas limits here: 
     7  - The outer min gas limit is for the call from the `OptimismPortal` to the `L1CrossDomainMessenger`,  and it can be retrieved by calling the xdm's `baseGas` function with the `message` and inner limit. 
     8  - The inner min gas limit is for the call from the `L1CrossDomainMessenger` to the target contract. 
     9  
    10  ## A call to `relayMessage` should assign the message hash to the `failedMessages` mapping if not enough gas is supplied to forward `minGasLimit` to the target context or if there is not enough gas to complete execution of `relayMessage` after the target context's execution is finished.
    11  **Test:** [`CrossDomainMessenger.t.sol#L176`](../test/invariants/CrossDomainMessenger.t.sol#L176)
    12  
    13  There are two minimum gas limits here: 
    14  - The outer min gas limit is for the call from the `OptimismPortal` to the `L1CrossDomainMessenger`,  and it can be retrieved by calling the xdm's `baseGas` function with the `message` and inner limit. 
    15  - The inner min gas limit is for the call from the `L1CrossDomainMessenger` to the target contract.