fix: handle retrieval deals with zero price per byte

docs/retrievalclient.mmd

@@ -24,6 +24,7 @@ stateDiagram-v2
 	state "DealStatusCancelled" as 26
 	state "DealStatusRetryLegacy" as 27
 	state "DealStatusWaitForAcceptanceLegacy" as 28
+	state "DealStatusWaitingForLastBlocks" as 29
 	0 : On entry runs ProposeDeal
 	4 : On entry runs WaitPaymentChannelReady
 	5 : On entry runs WaitPaymentChannelReady
@@ -82,9 +83,12 @@ stateDiagram-v2
 	13 --> 18 : ClientEventAllBlocksReceived
 	14 --> 12 : ClientEventAllBlocksReceived
 	18 --> 18 : ClientEventAllBlocksReceived
+	29 --> 15 : ClientEventAllBlocksReceived
 	10 --> 10 : ClientEventBlocksReceived
 	13 --> 13 : ClientEventBlocksReceived
 	14 --> 14 : ClientEventBlocksReceived
+	21 --> 21 : ClientEventBlocksReceived
+	29 --> 29 : ClientEventBlocksReceived
 	10 --> 11 : ClientEventSendFunds
 	14 --> 12 : ClientEventSendFunds
 	22 --> 23 : ClientEventFundsExpended
@@ -100,6 +104,7 @@ stateDiagram-v2
 	19 --> 15 : ClientEventComplete
 	21 --> 15 : ClientEventCompleteVerified
 	21 --> 17 : ClientEventEarlyTermination
+	21 --> 29 : ClientEventWaitForLastBlocks
 	8 --> 17 : ClientEventCancelComplete
 	25 --> 26 : ClientEventCancelComplete
 	23 --> 22 : ClientEventRecheckFunds

retrievalmarket/dealstatus.go

@@ -106,6 +106,13 @@ const (
 
 	// DealStatusWaitForAcceptanceLegacy means we're waiting to hear the results on the legacy protocol
 	DealStatusWaitForAcceptanceLegacy
+
+	// DealStatusClientWaitingForLastBlocks means that the provider has told
+	// the client that all blocks were sent for the deal, and the client is
+	// waiting for the last blocks to arrive. This should only happen when
+	// the deal price per byte is zero (if it's not zero the provider asks
+	// for final payment after sending the last blocks).
+	DealStatusClientWaitingForLastBlocks
 )
 
 // DealStatuses maps deal status to a human readable representation
@@ -139,4 +146,5 @@ var DealStatuses = map[DealStatus]string{
 	DealStatusCancelled:                    "DealStatusCancelled",
 	DealStatusRetryLegacy:                  "DealStatusRetryLegacy",
 	DealStatusWaitForAcceptanceLegacy:      "DealStatusWaitForAcceptanceLegacy",
+	DealStatusClientWaitingForLastBlocks:   "DealStatusWaitingForLastBlocks",
 }

retrievalmarket/events.go

@@ -114,6 +114,11 @@ const (
 
 	// ClientEventCancel runs when a user cancels a deal
 	ClientEventCancel
+
+	// ClientEventWaitForLastBlocks is fired when the provider has told
+	// the client that all blocks were sent for the deal, and the client is
+	// waiting for the last blocks to arrive
+	ClientEventWaitForLastBlocks
 )
 
 // ClientEvents is a human readable map of client event name -> event description
@@ -152,6 +157,7 @@ var ClientEvents = map[ClientEvent]string{
 	ClientEventVoucherShortfall:              "ClientEventVoucherShortfall",
 	ClientEventRecheckFunds:                  "ClientEventRecheckFunds",
 	ClientEventCancel:                        "ClientEventCancel",
+	ClientEventWaitForLastBlocks:             "ClientEventWaitForLastBlocks",
 }
 
 // ProviderEvent is an event that occurs in a deal lifecycle on the provider

retrievalmarket/impl/clientstates/client_fsm.go

@@ -178,14 +178,17 @@ var ClientEvents = fsm.Events{
 		FromMany(paymentChannelCreationStates...).ToJustRecord().
 		FromMany(rm.DealStatusSendFunds, rm.DealStatusFundsNeeded).ToJustRecord().
 		From(rm.DealStatusFundsNeededLastPayment).To(rm.DealStatusSendFundsLastPayment).
+		From(rm.DealStatusClientWaitingForLastBlocks).To(rm.DealStatusCompleted).
 		Action(func(deal *rm.ClientDealState) error {
 			deal.AllBlocksReceived = true
 			return nil
 		}),
 	fsm.Event(rm.ClientEventBlocksReceived).
 		FromMany(rm.DealStatusOngoing,
 			rm.DealStatusFundsNeeded,
-			rm.DealStatusFundsNeededLastPayment).ToNoChange().
+			rm.DealStatusFundsNeededLastPayment,
+			rm.DealStatusCheckComplete,
+			rm.DealStatusClientWaitingForLastBlocks).ToNoChange().
 		FromMany(paymentChannelCreationStates...).ToJustRecord().
 		Action(recordReceived),
 
@@ -260,6 +263,11 @@ var ClientEvents = fsm.Events{
 			return nil
 		}),
 
+	// the provider indicated that all blocks have been sent, so the client
+	// should wait for the last blocks to arrive
+	fsm.Event(rm.ClientEventWaitForLastBlocks).
+		From(rm.DealStatusCheckComplete).To(rm.DealStatusClientWaitingForLastBlocks),
+
 	// after cancelling a deal is complete
 	fsm.Event(rm.ClientEventCancelComplete).
 		From(rm.DealStatusFailing).To(rm.DealStatusErrored).

retrievalmarket/impl/clientstates/client_states.go

@@ -171,7 +171,19 @@ func CancelDeal(ctx fsm.Context, environment ClientDealEnvironment, deal rm.Clie
 
 // CheckComplete verifies that a provider that completed without a last payment requested did in fact send us all the data
 func CheckComplete(ctx fsm.Context, environment ClientDealEnvironment, deal rm.ClientDealState) error {
+	// The provider indicated that it has sent all the blocks
 	if !deal.AllBlocksReceived {
+		// If the deal price per byte is zero, wait for the last blocks to
+		// arrive
+		if deal.PricePerByte.IsZero() {
+			return ctx.Trigger(rm.ClientEventWaitForLastBlocks)
+		}
+
+		// If the deal price per byte is non-zero, the provider should only
+		// have sent the complete message after receiving the last payment
+		// from the client, which should happen after all blocks have been
+		// received. So if they haven't been received the provider is trying
+		// to terminate the deal early.
 		return ctx.Trigger(rm.ClientEventEarlyTermination)
 	}
 

retrievalmarket/impl/dtutils/dtutils.go

@@ -129,7 +129,7 @@ func clientEvent(event datatransfer.Event, channelState datatransfer.ChannelStat
 
 // ClientDataTransferSubscriber is the function called when an event occurs in a data
 // transfer initiated on the client -- it reads the voucher to verify this even occurred
-// in a storage market deal, then, based on the data transfer event that occurred, it dispatches
+// in a retrieval market deal, then, based on the data transfer event that occurred, it dispatches
 // an event to the appropriate state machine
 func ClientDataTransferSubscriber(deals EventReceiver) datatransfer.Subscriber {
 	return func(event datatransfer.Event, channelState datatransfer.ChannelState) {
@@ -148,7 +148,8 @@ func ClientDataTransferSubscriber(deals EventReceiver) datatransfer.Subscriber {
 		// data transfer events for progress do not affect deal state
 		err := deals.Send(dealProposal.ID, retrievalEvent, params...)
 		if err != nil {
-			log.Errorf("processing dt event: %w", err)
+			log.Errorf("processing dt event %s for state %s: %s",
+				datatransfer.Events[event.Code], datatransfer.Statuses[channelState.Status()], err)
 		}
 	}
 }

retrievalmarket/impl/integration_test.go

@@ -187,6 +187,7 @@ func TestClientCanMakeDealWithProvider(t *testing.T) {
 		voucherAmts             []abi.TokenAmount
 		selector                ipld.Node
 		unsealPrice             abi.TokenAmount
+		zeroPricePerByte        bool
 		paramsV1, addFunds      bool
 		skipStores              bool
 		failsUnseal             bool
@@ -260,6 +261,11 @@ func TestClientCanMakeDealWithProvider(t *testing.T) {
 			filesize:    19000,
 			voucherAmts: []abi.TokenAmount{abi.NewTokenAmount(10136000), abi.NewTokenAmount(9784000)},
 		},
+		{name: "multi-block file retrieval with zero price per byte succeeds",
+			filename:         "lorem.txt",
+			filesize:         19000,
+			zeroPricePerByte: true,
+		},
 		{name: "multi-block file retrieval succeeds with V1 params and AllSelector",
 			filename:    "lorem.txt",
 			filesize:    19000,
@@ -337,6 +343,9 @@ func TestClientCanMakeDealWithProvider(t *testing.T) {
 				paymentIntervalIncrease = uint64(1000)
 			}
 			pricePerByte := abi.NewTokenAmount(1000)
+			if testCase.zeroPricePerByte {
+				pricePerByte = abi.NewTokenAmount(0)
+			}
 			unsealPrice := testCase.unsealPrice
 			if unsealPrice.Int == nil {
 				unsealPrice = big.Zero()
@@ -509,9 +518,11 @@ CurrentInterval: %d
 				require.NotNil(t, createdChan)
 				require.Equal(t, expectedTotal, createdChan.amt)
 				require.Equal(t, clientPaymentChannel, *newLaneAddr)
-				// verify that the voucher was saved/seen by the client with correct values
-				require.NotNil(t, createdVoucher)
-				tut.TestVoucherEquality(t, createdVoucher, expectedVoucher)
+				if !testCase.zeroPricePerByte {
+					// verify that the voucher was saved/seen by the client with correct values
+					require.NotNil(t, createdVoucher)
+					tut.TestVoucherEquality(t, createdVoucher, expectedVoucher)
+				}
 				assert.Equal(t, retrievalmarket.DealStatusCompleted, clientDealState.Status)
 			}
 			ctx, cancel = context.WithTimeout(bgCtx, 5*time.Second)

retrievalmarket/impl/requestvalidation/revalidator.go

@@ -84,7 +84,9 @@ func (pr *ProviderRevalidator) loadDealState(channel *channelData) error {
 func (pr *ProviderRevalidator) writeDealState(deal rm.ProviderDealState) {
 	channel := pr.trackedChannels[deal.ChannelID]
 	channel.totalSent = deal.TotalSent
-	channel.totalPaidFor = big.Div(big.Max(big.Sub(deal.FundsReceived, deal.UnsealPrice), big.Zero()), deal.PricePerByte).Uint64()
+	if !deal.PricePerByte.IsZero() {
+		channel.totalPaidFor = big.Div(big.Max(big.Sub(deal.FundsReceived, deal.UnsealPrice), big.Zero()), deal.PricePerByte).Uint64()
+	}
 	channel.interval = deal.CurrentInterval
 	channel.pricePerByte = deal.PricePerByte
 	channel.legacyProtocol = deal.LegacyProtocol
@@ -195,19 +197,20 @@ func (pr *ProviderRevalidator) OnPullDataSent(chid datatransfer.ChannelID, addit
 	}
 
 	channel.totalSent += additionalBytesSent
-	if channel.totalSent-channel.totalPaidFor >= channel.interval {
-		paymentOwed := big.Mul(abi.NewTokenAmount(int64(channel.totalSent-channel.totalPaidFor)), channel.pricePerByte)
-		err := pr.env.SendEvent(channel.dealID, rm.ProviderEventPaymentRequested, channel.totalSent)
-		if err != nil {
-			return true, nil, err
-		}
-		return true, finalResponse(&rm.DealResponse{
-			ID:          channel.dealID.DealID,
-			Status:      rm.DealStatusFundsNeeded,
-			PaymentOwed: paymentOwed,
-		}, channel.legacyProtocol), datatransfer.ErrPause
+	if channel.pricePerByte.IsZero() || channel.totalSent-channel.totalPaidFor < channel.interval {
+		return true, nil, pr.env.SendEvent(channel.dealID, rm.ProviderEventBlockSent, channel.totalSent)
 	}
-	return true, nil, pr.env.SendEvent(channel.dealID, rm.ProviderEventBlockSent, channel.totalSent)
+
+	paymentOwed := big.Mul(abi.NewTokenAmount(int64(channel.totalSent-channel.totalPaidFor)), channel.pricePerByte)
+	err = pr.env.SendEvent(channel.dealID, rm.ProviderEventPaymentRequested, channel.totalSent)
+	if err != nil {
+		return true, nil, err
+	}
+	return true, finalResponse(&rm.DealResponse{
+		ID:          channel.dealID.DealID,
+		Status:      rm.DealStatusFundsNeeded,
+		PaymentOwed: paymentOwed,
+	}, channel.legacyProtocol), datatransfer.ErrPause
 }
 
 // OnPushDataReceived is called on the responder side when more bytes are received

retrievalmarket/impl/requestvalidation/revalidator_test.go

@@ -29,9 +29,11 @@ func TestOnPushDataReceived(t *testing.T) {
 	require.NoError(t, err)
 	require.Nil(t, voucherResult)
 }
-func TestOnPullDataSent(t *testing.T) {
 
+func TestOnPullDataSent(t *testing.T) {
 	deal := *makeDealState(rm.DealStatusOngoing)
+	dealZeroPricePerByte := deal
+	dealZeroPricePerByte.PricePerByte = big.Zero()
 	legacyDeal := deal
 	legacyDeal.LegacyProtocol = true
 	testCases := map[string]struct {
@@ -60,6 +62,15 @@ func TestOnPullDataSent(t *testing.T) {
 			expectedHandled: true,
 			dataAmount:      uint64(500),
 		},
+		"record block zero price per byte": {
+			deal:            dealZeroPricePerByte,
+			channelID:       dealZeroPricePerByte.ChannelID,
+			expectedID:      dealZeroPricePerByte.Identifier(),
+			expectedEvent:   rm.ProviderEventBlockSent,
+			expectedArgs:    []interface{}{dealZeroPricePerByte.TotalSent + uint64(500)},
+			expectedHandled: true,
+			dataAmount:      uint64(500),
+		},
 		"request payment": {
 			deal:          deal,
 			channelID:     deal.ChannelID,
@@ -125,6 +136,8 @@ func TestOnPullDataSent(t *testing.T) {
 
 func TestOnComplete(t *testing.T) {
 	deal := *makeDealState(rm.DealStatusOngoing)
+	dealZeroPricePerByte := deal
+	dealZeroPricePerByte.PricePerByte = big.Zero()
 	legacyDeal := deal
 	legacyDeal.LegacyProtocol = true
 	channelID := deal.ChannelID
@@ -210,6 +223,26 @@ func TestOnComplete(t *testing.T) {
 			deal:      deal,
 			channelID: channelID,
 		},
+		"all funds paid zero price per byte": {
+			unpaidAmount: uint64(0),
+			expectedEvents: []eventSent{
+				{
+					ID:    dealZeroPricePerByte.Identifier(),
+					Event: rm.ProviderEventBlockSent,
+					Args:  []interface{}{dealZeroPricePerByte.TotalSent},
+				},
+				{
+					ID:    dealZeroPricePerByte.Identifier(),
+					Event: rm.ProviderEventBlocksCompleted,
+				},
+			},
+			expectedResult: &rm.DealResponse{
+				ID:     dealZeroPricePerByte.ID,
+				Status: rm.DealStatusCompleted,
+			},
+			deal:      dealZeroPricePerByte,
+			channelID: channelID,
+		},
 		"all funds paid, legacyDeal": {
 			unpaidAmount: uint64(0),
 			expectedEvents: []eventSent{