feat: removed zero postings entirely

internal/interpreter/interpreter.go

@@ -247,6 +247,20 @@ type programState struct {
 	CurrentBalanceQuery BalanceQuery
 }
 
+func (st *programState) pushSender(name string, monetary *big.Int) {
+	if monetary.Cmp(big.NewInt(0)) == 0 {
+		return
+	}
+	st.Senders = append(st.Senders, Sender{Name: name, Monetary: monetary})
+}
+
+func (st *programState) pushReceiver(name string, monetary *big.Int) {
+	if monetary.Cmp(big.NewInt(0)) == 0 {
+		return
+	}
+	st.Receivers = append(st.Receivers, Receiver{Name: name, Monetary: monetary})
+}
+
 func (st *programState) runStatement(statement parser.Statement) ([]Posting, InterpreterError) {
 	st.Senders = nil
 	st.Receivers = nil
@@ -413,10 +427,7 @@ func (s *programState) sendAllToAccount(accountLiteral parser.ValueExpr, ovedraf
 
 	// we sent balance+overdraft
 	sentAmt := new(big.Int).Add(balance, ovedraft)
-	s.Senders = append(s.Senders, Sender{
-		Name:     *account,
-		Monetary: sentAmt,
-	})
+	s.pushSender(*account, sentAmt)
 	return sentAmt, nil
 }
 
@@ -506,10 +517,7 @@ func (s *programState) trySendingToAccount(accountLiteral parser.ValueExpr, amou
 		actuallySentAmt = utils.MinBigInt(safeSendAmt, amount)
 	}
 
-	s.Senders = append(s.Senders, Sender{
-		Name:     *account,
-		Monetary: actuallySentAmt,
-	})
+	s.pushSender(*account, actuallySentAmt)
 	return actuallySentAmt, nil
 }
 
@@ -585,10 +593,7 @@ func (s *programState) receiveFrom(destination parser.Destination, amount *big.I
 		if err != nil {
 			return err
 		}
-		s.Receivers = append(s.Receivers, Receiver{
-			Name:     *account,
-			Monetary: amount,
-		})
+		s.pushReceiver(*account, amount)
 		return nil
 
 	case *parser.DestinationAllotment:
@@ -659,13 +664,12 @@ func (s *programState) receiveFrom(destination parser.Destination, amount *big.I
 	}
 }
 
+const KEPT_ADDR = "<kept>"
+
 func (s *programState) receiveFromKeptOrDest(keptOrDest parser.KeptOrDestination, amount *big.Int) InterpreterError {
 	switch destinationTarget := keptOrDest.(type) {
 	case *parser.DestinationKept:
-		s.Receivers = append(s.Receivers, Receiver{
-			Name:     "<kept>",
-			Monetary: amount,
-		})
+		s.pushReceiver(KEPT_ADDR, amount)
 		return nil
 
 	case *parser.DestinationTo:

internal/interpreter/interpreter_test.go

@@ -1731,7 +1731,6 @@ func TestDestinationComplex(t *testing.T) {
 // TODO TestNeededBalances, TestSetTxMeta, TestSetAccountMeta
 
 func TestSendZero(t *testing.T) {
-	// TODO double check
 	tc := NewTestCase()
 	tc.compile(t, `
 	send [COIN 0] (
@@ -1740,6 +1739,7 @@ func TestSendZero(t *testing.T) {
 	)`)
 	tc.expected = CaseResult{
 		Postings: []Posting{
+			// Zero posting is omitted
 			// {
 			// 	Asset:       "COIN",
 			// 	Amount:      big.NewInt(0),
@@ -1815,7 +1815,6 @@ func TestNegativeBalanceLiteral(t *testing.T) {
 }
 
 func TestBalanceNotFound(t *testing.T) {
-	// TODO double check
 	tc := NewTestCase()
 	tc.compile(t, `
 	vars {
@@ -1828,6 +1827,7 @@ func TestBalanceNotFound(t *testing.T) {
 	)`)
 	tc.expected = CaseResult{
 		Postings: []Posting{
+			// Zero posting is omitted
 			// {
 			// 	Asset:       "EUR/2",
 			// 	Amount:      big.NewInt(0),
@@ -2683,6 +2683,41 @@ func TestZeroPostingsDestination(t *testing.T) {
 	test(t, tc)
 }
 
+func TestZeroPostingsExplicitInorder(t *testing.T) {
+	tc := NewTestCase()
+	tc.compile(t, `
+	send [COIN 0] (
+		source = {
+			@a
+			@b
+			@c
+		}
+		destination = @dest
+	)
+	`)
+	tc.expected = CaseResult{
+		Postings: []machine.Posting{},
+	}
+	test(t, tc)
+}
+
+func TestZeroPostingsExplicitAllotment(t *testing.T) {
+	tc := NewTestCase()
+	tc.compile(t, `
+	send [COIN 0] (
+		source = {
+			1/2 from @a
+			1/2 from @b
+		}
+		destination = @dest
+	)
+	`)
+	tc.expected = CaseResult{
+		Postings: []machine.Posting{},
+	}
+	test(t, tc)
+}
+
 func TestUnboundedOverdraftWhenNotEnoughFunds(t *testing.T) {
 	tc := NewTestCase()
 	tc.setBalance("users:2345:main", "USD/2", 8000)

internal/interpreter/reconciler.go

@@ -33,13 +33,6 @@ type Receiver struct {
 }
 
 func Reconcile(asset string, senders []Sender, receivers []Receiver) ([]Posting, InterpreterError) {
-	var sendersFiltered []Sender
-	for _, e := range senders {
-		if e.Monetary.Cmp(big.NewInt(0)) != 0 {
-			sendersFiltered = append(sendersFiltered, e)
-		}
-	}
-	senders = sendersFiltered
 
 	// We reverse senders and receivers once so that we can
 	// treat them as stack and push/pop in O(1)
@@ -54,7 +47,7 @@ func Reconcile(asset string, senders []Sender, receivers []Receiver) ([]Posting,
 		}
 
 		// Ugly workaround
-		if receiver.Name == "<kept>" {
+		if receiver.Name == KEPT_ADDR {
 			sender, empty := popStack(&senders)
 			if !empty {
 				var newMon big.Int

internal/interpreter/reconciler_test.go

@@ -43,15 +43,14 @@ func TestReconcileSingletonExactMatch(t *testing.T) {
 }
 
 func TestReconcileZero(t *testing.T) {
-	// TODO double check
 	runReconcileTestCase(t, ReconcileTestCase{
 		Currency:  "COIN",
 		Senders:   []Sender{{"src", big.NewInt(0)}},
 		Receivers: []Receiver{{"dest", big.NewInt(0)}},
-		Expected:  nil,
-		// []Posting{
-		// 	// {"src", "dest", big.NewInt(0), "COIN"}
-		// },
+		Expected: []Posting{
+			{"src", "dest", big.NewInt(0), "COIN"},
+		},
+		ExpectedErr: nil,
 	})
 }