The function updateAndQuery of EMAOracle.sol subtracts the incomeIndex with the previous incomeIndex.
These incomeIndex values are retrieved via the moneyMarket contract from an external contract.
If, by accident, the previous incomeIndex is larger than the current incomeIndex, then the subtraction would be negative and the code halts (reverts) without an error message.
Also, the updateAndQuery function would not be able to execute (until the current incomeIndex is larger than the previous incomeIndex).
This situation could occur when an error occurs in one of the current or future money markets.
Recommend giving an error message when the previous incomeIndex is larger than the current incomeIndex and/or create a way to recover from this erroneous situation.
ZeframLou (88mph) confirmed:
