fix(vbank): ensure that multiple balance updates are sorted

go.sum

@@ -293,6 +293,7 @@ github.com/golang/mock v1.4.1/go.mod h1:UOMv5ysSaYNkG+OFQykRIcU/QvvxJf3p21QfJ2Bt
 github.com/golang/mock v1.4.3/go.mod h1:UOMv5ysSaYNkG+OFQykRIcU/QvvxJf3p21QfJ2Bt3cw=
 github.com/golang/mock v1.4.4 h1:l75CXGRSwbaYNpl/Z2X1XIIAMSCquvXgpVZDhwEIJsc=
 github.com/golang/mock v1.4.4/go.mod h1:l3mdAwkq5BuhzHwde/uurv3sEJeZMXNpwsxVWU71h+4=
+github.com/golang/mock v1.5.0 h1:jlYHihg//f7RRwuPfptm04yp4s7O6Kw8EZiVYIGcH0g=
 github.com/golang/mock v1.5.0/go.mod h1:CWnOUgYIOo4TcNZ0wHX3YZCqsaM1I1Jvs6v3mP3KVu8=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.0/go.mod h1:Qd/q+1AKNOZr9uGQzbzCmRO6sUih6GTPZv6a1/R87v0=

golang/cosmos/x/vbank/vbank.go

@@ -3,6 +3,7 @@ package vbank
 import (
 	"encoding/json"
 	"fmt"
+	"sort"
 
 	"github.com/Agoric/agoric-sdk/golang/cosmos/vm"
 	sdk "github.com/cosmos/cosmos-sdk/types"
@@ -35,10 +36,37 @@ type vbankSingleBalanceUpdate struct {
 	Amount  string `json:"amount"`
 }
 
+// Make vbankManyBalanceUpdates sortable
+type vbankManyBalanceUpdates []vbankSingleBalanceUpdate
+
+var _ sort.Interface = vbankManyBalanceUpdates{}
+
+func (vbu vbankManyBalanceUpdates) Len() int {
+	return len(vbu)
+}
+
+func (vbu vbankManyBalanceUpdates) Less(i int, j int) bool {
+	if vbu[i].Address < vbu[j].Address {
+		return true
+	} else if vbu[i].Address > vbu[j].Address {
+		return false
+	}
+	if vbu[i].Denom < vbu[j].Denom {
+		return true
+	} else if vbu[i].Denom > vbu[j].Denom {
+		return false
+	}
+	return vbu[i].Amount < vbu[j].Amount
+}
+
+func (vbu vbankManyBalanceUpdates) Swap(i int, j int) {
+	vbu[i], vbu[j] = vbu[j], vbu[i]
+}
+
 type vbankBalanceUpdate struct {
-	Nonce   uint64                     `json:"nonce"`
-	Type    string                     `json:"type"`
-	Updated []vbankSingleBalanceUpdate `json:"updated"`
+	Nonce   uint64                  `json:"nonce"`
+	Type    string                  `json:"type"`
+	Updated vbankManyBalanceUpdates `json:"updated"`
 }
 
 func marshalBalanceUpdate(ctx sdk.Context, keeper Keeper, addressToBalance map[string]sdk.Coins) ([]byte, error) {
@@ -53,6 +81,9 @@ func marshalBalanceUpdate(ctx sdk.Context, keeper Keeper, addressToBalance map[s
 		Nonce:   nonce,
 		Updated: make([]vbankSingleBalanceUpdate, 0, nentries),
 	}
+
+	// Note that Golang randomises the order of iteration, so we have to sort
+	// below to be deterministic.
 	for address, coins := range addressToBalance {
 		for _, coin := range coins {
 			update := vbankSingleBalanceUpdate{
@@ -64,6 +95,8 @@ func marshalBalanceUpdate(ctx sdk.Context, keeper Keeper, addressToBalance map[s
 		}
 	}
 
+	// Ensure we have a deterministic order of updates.
+	sort.Sort(event.Updated)
 	return json.Marshal(&event)
 }
 

golang/cosmos/x/vbank/vbank_test.go

@@ -82,7 +82,11 @@ func decodeBalances(encoded []byte) (balances, uint64, error) {
 		return nil, 0, fmt.Errorf("bad balance update type: %s", balanceUpdate.Type)
 	}
 	b := newBalances()
-	for _, u := range balanceUpdate.Updated {
+	fmt.Printf("updated balances %v\n", balanceUpdate.Updated)
+	for i, u := range balanceUpdate.Updated {
+		if i < len(balanceUpdate.Updated)-1 && balanceUpdate.Updated.Less(i+1, i) {
+			return nil, 0, fmt.Errorf("unordered balance update %v is before %v", u, balanceUpdate.Updated[i+1])
+		}
 		account(u.Address, coin(u.Denom, u.Amount))(b)
 	}
 	return b, balanceUpdate.Nonce, nil
@@ -99,6 +103,7 @@ func Test_marshalBalanceUpdate(t *testing.T) {
 		addressToBalance map[string]sdk.Coins
 		want             balances
 		wantErr          bool
+		encoded          []byte
 	}{
 		{
 			name:             "empty",
@@ -277,8 +282,9 @@ func Test_Receive_Give(t *testing.T) {
 	want := newBalances(account(addr1, coin("urun", "1000")))
 	got, gotNonce, err := decodeBalances([]byte(ret))
 	if err != nil {
-		t.Errorf("decode balances error = %v", err)
-	} else if !reflect.DeepEqual(got, want) {
+		t.Fatalf("decode balances error = %v", err)
+	}
+	if !reflect.DeepEqual(got, want) {
 		t.Errorf("got %+v, want %+v", got, want)
 	}
 	nonce := uint64(1)
@@ -418,8 +424,9 @@ func Test_Receive_Grab(t *testing.T) {
 	want := newBalances(account(addr1, coin("ubld", "1000")))
 	got, gotNonce, err := decodeBalances([]byte(ret))
 	if err != nil {
-		t.Errorf("decode balances error = %v", err)
-	} else if !reflect.DeepEqual(got, want) {
+		t.Fatalf("decode balances error = %v", err)
+	}
+	if !reflect.DeepEqual(got, want) {
 		t.Errorf("got %+v, want %+v", got, want)
 	}
 	nonce := uint64(1)
@@ -495,7 +502,7 @@ func Test_EndBlock_Events(t *testing.T) {
 	}
 	gotMsg, gotNonce, err := decodeBalances([]byte(msgsSent[0]))
 	if err != nil {
-		t.Errorf("decode balances error = %v", err)
+		t.Fatalf("decode balances error = %v", err)
 	}
 
 	nonce := uint64(1)