feat(sdk/vm): support return values from main in msgrun

gno.land/cmd/gnoland/testdata/run.txtar

@@ -8,7 +8,7 @@ gnokey maketx addpkg -pkgdir $WORK/bar -pkgpath gno.land/r/foobar/bar -gas-fee 1
 gnokey maketx run -gas-fee 1000000ugnot -gas-wanted 2000000 -broadcast -chainid=tendermint_test test1 $WORK/script/script.gno
 
 ## compare render
-stdout 'main: --- hello from foo ---'
+stdout '("main: --- hello from foo ---" string)'
 stdout 'OK!'
 stdout 'GAS WANTED: 200000'
 stdout 'GAS USED: '
@@ -23,6 +23,6 @@ func Render(path string) string {
 -- script/script.gno --
 package main
 import "gno.land/r/foobar/bar"
-func main() {
-	println("main: ---", bar.Render(""), "---")
+func main() string {
+	return "main: --- " + bar.Render("") + " ---"
 }

gno.land/pkg/gnoclient/client_test.go

@@ -68,17 +68,20 @@ func TestClient_Run(t *testing.T) {
 
 import (
 	"std"
+	"strings"
 
 	"gno.land/p/demo/ufmt"
 	"gno.land/r/demo/tests"
 )
 
-func main() {
-	println(ufmt.Sprintf("- before: %d", tests.Counter()))
+func main() string {
+	var buf strings.Builder
+	buf.WriteString(ufmt.Sprintf("- before: %d\n", tests.Counter()))
 	for i := 0; i < 10; i++ {
 		tests.IncCounter()
 	}
-	println(ufmt.Sprintf("- after: %d", tests.Counter()))
+	buf.WriteString(ufmt.Sprintf("- after: %d\n", tests.Counter()))
+	return buf.String()
 }`
 	memPkg := &std.MemPackage{
 		Files: []*std.MemFile{
@@ -96,5 +99,5 @@ func main() {
 	require.NoError(t, err)
 	require.NotNil(t, res)
 	require.NotEmpty(t, res.DeliverTx.Data)
-	require.Equal(t, string(res.DeliverTx.Data), "- before: 0\n- after: 10\n")
+	require.Contains(t, string(res.DeliverTx.Data), `"- before: 0\n- after: 10\n"`)
 }

gno.land/pkg/integration/testdata/adduser.txtar

@@ -29,6 +29,6 @@ func Render(path string) string {
 -- script/script.gno --
 package main
 import "gno.land/r/foobar/bar"
-func main() {
-	println("main: ---", bar.Render(""), "---")
+func main() string {
+	return "main: --- " + bar.Render("") + " ---"
 }

gno.land/pkg/sdk/vm/keeper.go

@@ -3,9 +3,8 @@
 // TODO: move most of the logic in ROOT/gno.land/...
 
 import (
-	"bytes"
 	"fmt"
-	"os"
+	"io"
 	"regexp"
 	"strings"
 
@@ -85,7 +84,7 @@
 		m2 := gno.NewMachineWithOptions(
 			gno.MachineOptions{
 				PkgPath: "",
-				Output:  os.Stdout, // XXX
+				Output:  io.Discard,
 				Store:   vm.gnoStore,
 			})
 		defer m2.Release()
@@ -192,7 +191,7 @@
 	m2 := gno.NewMachineWithOptions(
 		gno.MachineOptions{
 			PkgPath:   "",
-			Output:    os.Stdout, // XXX
+			Output:    io.Discard,
 			Store:     store,
 			Alloc:     store.GetAllocator(),
 			Context:   msgCtx,
@@ -267,7 +266,7 @@
 	m := gno.NewMachineWithOptions(
 		gno.MachineOptions{
 			PkgPath:   "",
-			Output:    os.Stdout, // XXX
+			Output:    io.Discard,
 			Store:     store,
 			Context:   msgCtx,
 			Alloc:     store.GetAllocator(),
@@ -330,11 +329,10 @@
 		Banker:        NewSDKBanker(vm, ctx),
 	}
 	// Parse and run the files, construct *PV.
-	buf := new(bytes.Buffer)
 	m := gno.NewMachineWithOptions(
 		gno.MachineOptions{
 			PkgPath:   "",
-			Output:    buf,
+			Output:    io.Discard,
 			Store:     store,
 			Alloc:     store.GetAllocator(),
 			Context:   msgCtx,
@@ -347,7 +345,7 @@
 	m2 := gno.NewMachineWithOptions(
 		gno.MachineOptions{
 			PkgPath:   "",
-			Output:    buf,
+			Output:    io.Discard,
 			Store:     store,
 			Alloc:     store.GetAllocator(),
 			Context:   msgCtx,
@@ -362,11 +360,15 @@
 		}
 		m2.Release()
 	}()
-	m2.RunMain()
-	ctx.Logger().Info("CPUCYCLES call",
-		"cycles", m2.Cycles,
-	)
-	res = buf.String()
+
+	rtvs := m2.Eval(gno.Call(gno.X("main")))
+	ctx.Logger().Info("CPUCYCLES call", "num-cycles", m2.Cycles)
+	for i, rtv := range rtvs {
+		res = res + rtv.String()
+		if i < len(rtvs)-1 {
+			res += "\n"
+		}
+	}
 	return res, nil
 }
 
@@ -464,7 +466,7 @@
 	m := gno.NewMachineWithOptions(
 		gno.MachineOptions{
 			PkgPath:   pkgPath,
-			Output:    os.Stdout, // XXX
+			Output:    io.Discard,
 			Store:     store,
 			Context:   msgCtx,
 			Alloc:     alloc,
@@ -524,7 +526,7 @@
 	m := gno.NewMachineWithOptions(
 		gno.MachineOptions{
 			PkgPath:   pkgPath,
-			Output:    os.Stdout, // XXX
+			Output:    io.Discard,
 			Store:     store,
 			Context:   msgCtx,
 			Alloc:     alloc,

gno.land/pkg/sdk/vm/keeper_test.go

@@ -352,8 +352,8 @@ func TestVMKeeperRunSimple(t *testing.T) {
 		{"script.gno", `
 package main
 
-func main() {
-	println("hello world!")
+func main() string {
+	return "hello world!"
 }
 `},
 	}
@@ -362,7 +362,7 @@ func main() {
 	msg2 := NewMsgRun(addr, coins, files)
 	res, err := env.vmk.Run(ctx, msg2)
 	assert.NoError(t, err)
-	assert.Equal(t, res, "hello world!\n")
+	assert.Contains(t, res, `"hello world!" string`)
 }
 
 // Call Run with stdlibs.
@@ -381,9 +381,9 @@ package main
 
 import "std"
 
-func main() {
+func main() string {
 	addr := std.GetOrigCaller()
-	println("hello world!", addr)
+	return "hello world! " + addr.String()
 }
 `},
 	}
@@ -392,6 +392,6 @@ func main() {
 	msg2 := NewMsgRun(addr, coins, files)
 	res, err := env.vmk.Run(ctx, msg2)
 	assert.NoError(t, err)
-	expectedString := fmt.Sprintf("hello world! %s\n", addr.String())
-	assert.Equal(t, res, expectedString)
+	expectedString := fmt.Sprintf("hello world! %s", addr.String())
+	assert.Contains(t, res, expectedString)
 }