Market State.dealGetPaymentRemaining: Bad assertion allows for panic

[wadealexc]

specs-actors/actors/builtin/market/market_state.go

Lines 225 to 234 in 2540928

	func dealGetPaymentRemaining(deal *DealProposal, slashEpoch abi.ChainEpoch) abi.TokenAmount {
	Assert(slashEpoch <= deal.EndEpoch)
	// Payments are always for start -> end epoch irrespective of when the deal is slashed.
	if slashEpoch < deal.StartEpoch {
	slashEpoch = deal.StartEpoch
	}
	durationRemaining := deal.EndEpoch - slashEpoch
	Assert(durationRemaining > 0)

Assert(durationRemaining > 0) does not account for the case where slashEpoch == deal.EndEpoch.

(This shouldn't happen as OnMinerSectorsTerminate will not allow a slash epoch to be set for expired deals.)