Protorev Out Of Gas

[NotJeremyLiu]

Background

• With the new hook based approach, Protorev now stores swaps to backrun in state when triggered by GAMM and Concentrated Liquidity pool after swap hooks:

• osmosis/x/protorev/keeper/hooks.go

  Line 56 in b7fe65f

  func (h Hooks) AfterCFMMSwap(ctx sdk.Context, sender sdk.AccAddress, poolId uint64, input sdk.Coins, output sdk.Coins) {

• osmosis/x/protorev/keeper/hooks.go

  Line 83 in b7fe65f

  func (h Hooks) AfterConcentratedPoolSwap(ctx sdk.Context, sender sdk.AccAddress, poolId uint64, input sdk.Coins, output sdk.Coins) {

• Then, in the posthandler, ProtoRev deletes these stored swaps from state, regardless of the outcome of the rebalancing logic:

• osmosis/x/protorev/keeper/posthandler.go

  Line 66 in b7fe65f

  protoRevDec.ProtoRevKeeper.DeleteSwapsToBackrun(ctx.WithGasMeter(upperGasLimitMeter))

• The issue is that the upperGasLimitMeter used to delete the swaps to backrun from store on the real ctx is the same upperGasLimitMeter used in the cachectx to perform the rebalancing logic. So, if within the rebalancing logic the upperGasLimitMeter is depleted, the call to DeleteSwapsToBackrun will fail with an out of gas error, resulting in a failed transaction for the user.

Suggested Design

• Use an sdk.NewInfiniteGasMeter in the DeleteSwapsToBackrun call so that it never has the chance to run out of gas and fail the user's transaction. Using an infinite gas meter here should be safe as there is no looping logic within the DeleteSwapsToBackrun and the most number of swaps that is allowed to be stored in state in this kv store would be # of swaps the user took + # of swaps protorev performed to backrun.
• Alternatively, instead of using an infinite gas meter, we could use a new large gas meter (if using an infinite gas meter is unacceptable)

Acceptance Criteria

• Add and pass a test that depletes the gas meter used in the cachectx where protorev performs the rebalancing logic, while still successfully deleting the swaps from the kvstores and not failing the user's transaction.