Fix vartuple handling for nested objects

gen/decode.go

@@ -201,7 +201,8 @@ func (d *decodeGen) structAsTuple(s *Struct) {
 	d.p.declare(sz, u32)
 	d.assignArray(sz, arrayHeader, 0)
 	if s.AsVarTuple {
-		d.p.printf("\nif %[1]s == 0 { return }", sz)
+		d.p.printf("\nfor range 1 {")               // start the block
+		d.p.printf("\nif %[1]s == 0 { break }", sz) // exit from the block
 	} else {
 		d.p.arrayCheck(strconv.Itoa(len(s.Fields)), sz)
 	}
@@ -239,11 +240,12 @@ func (d *decodeGen) structAsTuple(s *Struct) {
 			d.p.printf("\n}") // close if statement
 		}
 		if s.AsVarTuple {
-			d.p.printf("\nif %[1]s--; %[1]s == 0 { return }", sz)
+			d.p.printf("\nif %[1]s--; %[1]s == 0 { break }", sz) // exit from the block
 		}
 	}
 	if s.AsVarTuple {
 		d.p.printf("\nfor ; %[1]s > 0; %[1]s-- {\nif err = dc.Skip(); err != nil {\nerr = msgp.WrapError(err)\nreturn\n}\n}", sz)
+		d.p.printf("\n}") // end the block
 	}
 }
 

gen/unmarshal.go

@@ -223,7 +223,8 @@ func (u *unmarshalGen) tuple(s *Struct) {
 	u.p.declare(sz, u32)
 	u.assignAndCheck(sz, arrayHeader)
 	if s.AsVarTuple {
-		u.p.printf("\nif %[1]s == 0 {\no = bts\nreturn\n}", sz)
+		u.p.printf("\nfor range 1 {")                          // start the block
+		u.p.printf("\nif %[1]s == 0 {\no = bts\nbreak\n}", sz) // exit from the block
 	} else {
 		u.p.arrayCheck(strconv.Itoa(len(s.Fields)), sz)
 	}
@@ -265,11 +266,12 @@ func (u *unmarshalGen) tuple(s *Struct) {
 			u.p.printf("\n}")
 		}
 		if s.AsVarTuple {
-			u.p.printf("\nif %[1]s--; %[1]s == 0 {\no = bts\nreturn\n}", sz)
+			u.p.printf("\nif %[1]s--; %[1]s == 0 {\no = bts\nbreak\n}", sz) // exit from the block
 		}
 	}
 	if s.AsVarTuple {
 		u.p.printf("\nfor ; %[1]s > 0; %[1]s-- {\nbts, err = msgp.Skip(bts)\nif err != nil {\nerr = msgp.WrapError(err)\nreturn\n}\n}", sz)
+		u.p.printf("\n}") // end the block
 	}
 }
 

issue430_test.go

@@ -0,0 +1,60 @@
+package main
+
+import "testing"
+
+func TestIssue430Nested(t *testing.T) {
+	mainFilename, err := generate(t, issue430Nested)
+	if err != nil {
+		t.Fatalf("generate failed: %v", err)
+	}
+
+	goExec(t, mainFilename, false) // exec go run
+	goExec(t, mainFilename, true)  // exec go test
+}
+
+var issue430Nested = `package main
+
+import (
+	"fmt"
+	"os"
+)
+
+//go:generate msgp
+
+//msgp:vartuple Bag
+type Bag struct {
+	ItemID  uint32
+	ItemNum uint32
+}
+
+//msgp:vartuple User
+type User struct {
+	Name string
+	Bag  []*Bag
+}
+
+func main() {
+	u := User{Name: "user", Bag: []*Bag{{1, 2}, {3, 4}}}
+	data, err := u.MarshalMsg(nil)
+	if err != nil {
+		fmt.Println("User MarshalMsg failed:", err)
+		os.Exit(1)
+	}
+
+	var user User
+	if _, err := user.UnmarshalMsg(data); err != nil {
+		fmt.Println("User UnmarshalMsg failed:", err)
+		os.Exit(1)
+	}
+	if user.Name != "user" ||
+		user.Bag[0] == nil ||
+		user.Bag[0].ItemID != 1 ||
+		user.Bag[0].ItemNum != 2 ||
+		user.Bag[1] == nil ||
+		user.Bag[1].ItemID != 3 ||
+		user.Bag[1].ItemNum != 4 {
+		fmt.Println("User UnmarshalMsg bad user:", user)
+		os.Exit(1)
+	}
+}
+`