retrieval: skip payment channel creation if total price is zero (#480)

* feat: skip payment channel creation if total price is zero

* fix: add missing event name

docs/retrievalclient.mmd

@@ -63,6 +63,7 @@ stateDiagram-v2
 	4 --> 8 : ClientEventPaymentChannelErrored
 	5 --> 8 : ClientEventPaymentChannelErrored
 	6 --> 8 : ClientEventPaymentChannelErrored
+	6 --> 13 : ClientEventPaymentChannelSkip
 	6 --> 4 : ClientEventPaymentChannelCreateInitiated
 	6 --> 24 : ClientEventPaymentChannelAddingFunds
 	22 --> 5 : ClientEventPaymentChannelAddingFunds
@@ -101,6 +102,7 @@ stateDiagram-v2
 	11 --> 13 : ClientEventPaymentSent
 	12 --> 19 : ClientEventPaymentSent
 	13 --> 21 : ClientEventComplete
+	18 --> 21 : ClientEventComplete
 	19 --> 15 : ClientEventComplete
 	21 --> 15 : ClientEventCompleteVerified
 	21 --> 17 : ClientEventEarlyTermination

retrievalmarket/events.go

@@ -119,6 +119,10 @@ const (
 	// the client that all blocks were sent for the deal, and the client is
 	// waiting for the last blocks to arrive
 	ClientEventWaitForLastBlocks
+
+	// ClientEventPaymentChannelSkip is fired when the total deal price is zero
+	// so there's no need to set up a payment channel
+	ClientEventPaymentChannelSkip
 )
 
 // ClientEvents is a human readable map of client event name -> event description
@@ -158,6 +162,7 @@ var ClientEvents = map[ClientEvent]string{
 	ClientEventRecheckFunds:                  "ClientEventRecheckFunds",
 	ClientEventCancel:                        "ClientEventCancel",
 	ClientEventWaitForLastBlocks:             "ClientEventWaitForLastBlocks",
+	ClientEventPaymentChannelSkip:            "ClientEventPaymentChannelSkip",
 }
 
 // ProviderEvent is an event that occurs in a deal lifecycle on the provider

retrievalmarket/impl/clientstates/client_fsm.go

@@ -80,12 +80,18 @@ var ClientEvents = fsm.Events{
 			deal.Message = xerrors.Errorf("error from payment channel: %w", err).Error()
 			return nil
 		}),
+
+	// Price of deal is zero so skip creating a payment channel
+	fsm.Event(rm.ClientEventPaymentChannelSkip).
+		From(rm.DealStatusAccepted).To(rm.DealStatusOngoing),
+
 	fsm.Event(rm.ClientEventPaymentChannelCreateInitiated).
 		From(rm.DealStatusAccepted).To(rm.DealStatusPaymentChannelCreating).
 		Action(func(deal *rm.ClientDealState, msgCID cid.Cid) error {
 			deal.WaitMsgCID = &msgCID
 			return nil
 		}),
+
 	fsm.Event(rm.ClientEventPaymentChannelAddingFunds).
 		FromMany(rm.DealStatusAccepted).To(rm.DealStatusPaymentChannelAllocatingLane).
 		FromMany(rm.DealStatusCheckFunds).To(rm.DealStatusPaymentChannelAddingFunds).
@@ -98,6 +104,7 @@ var ClientEvents = fsm.Events{
 			}
 			return nil
 		}),
+
 	fsm.Event(rm.ClientEventPaymentChannelReady).
 		From(rm.DealStatusPaymentChannelCreating).To(rm.DealStatusPaymentChannelAllocatingLane).
 		From(rm.DealStatusPaymentChannelAddingFunds).To(rm.DealStatusOngoing).
@@ -113,6 +120,7 @@ var ClientEvents = fsm.Events{
 			deal.Message = ""
 			return nil
 		}),
+
 	fsm.Event(rm.ClientEventAllocateLaneErrored).
 		FromMany(rm.DealStatusPaymentChannelAllocatingLane).
 		To(rm.DealStatusFailing).
@@ -253,6 +261,7 @@ var ClientEvents = fsm.Events{
 	// completing deals
 	fsm.Event(rm.ClientEventComplete).
 		From(rm.DealStatusOngoing).To(rm.DealStatusCheckComplete).
+		From(rm.DealStatusBlocksComplete).To(rm.DealStatusCheckComplete).
 		From(rm.DealStatusFinalizing).To(rm.DealStatusCompleted),
 	fsm.Event(rm.ClientEventCompleteVerified).
 		From(rm.DealStatusCheckComplete).To(rm.DealStatusCompleted),

retrievalmarket/impl/clientstates/client_states.go

@@ -36,6 +36,10 @@ func ProposeDeal(ctx fsm.Context, environment ClientDealEnvironment, deal rm.Cli
 
 // SetupPaymentChannelStart initiates setting up a payment channel for a deal
 func SetupPaymentChannelStart(ctx fsm.Context, environment ClientDealEnvironment, deal rm.ClientDealState) error {
+	// If the total funds required for the deal are zero, skip creating the payment channel
+	if deal.TotalFunds.IsZero() {
+		return ctx.Trigger(rm.ClientEventPaymentChannelSkip)
+	}
 
 	tok, _, err := environment.Node().GetChainHead(ctx.Context())
 	if err != nil {

retrievalmarket/impl/clientstates/client_states_test.go

@@ -146,6 +146,14 @@ func TestSetupPaymentChannel(t *testing.T) {
 		require.Equal(t, dealState.Status, retrievalmarket.DealStatusFailing)
 	})
 
+	t.Run("payment channel skip if total funds is zero", func(t *testing.T) {
+		envParams := testnodes.TestRetrievalClientNodeParams{}
+		dealState := makeDealState(retrievalmarket.DealStatusAccepted)
+		dealState.TotalFunds = abi.NewTokenAmount(0)
+		runSetupPaymentChannel(t, envParams, dealState)
+		assert.Empty(t, dealState.Message)
+		assert.Equal(t, dealState.Status, retrievalmarket.DealStatusOngoing)
+	})
 }
 
 func TestWaitForPaymentReady(t *testing.T) {

retrievalmarket/impl/integration_test.go

@@ -514,11 +514,12 @@ CurrentInterval: %d
 			} else if testCase.cancelled {
 				assert.Equal(t, retrievalmarket.DealStatusCancelled, clientDealState.Status)
 			} else {
-				assert.Equal(t, clientDealState.PaymentInfo.Lane, expectedVoucher.Lane)
-				require.NotNil(t, createdChan)
-				require.Equal(t, expectedTotal, createdChan.amt)
-				require.Equal(t, clientPaymentChannel, *newLaneAddr)
 				if !testCase.zeroPricePerByte {
+					assert.Equal(t, clientDealState.PaymentInfo.Lane, expectedVoucher.Lane)
+					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)