fix: catch runtime panic

gnovm/pkg/gnolang/machine.go

@@ -1191,6 +1191,20 @@ const (
 // main run loop.
 
 func (m *Machine) Run() {
+	defer func() {
+		if r := recover(); r != nil {
+			switch r := r.(type) {
+			case []Exception:
+				panic(m.buildPanicString(r))
+			case error:
+				m.Panic(typedString(r.Error()))
+			default:
+				m.Panic(typedString(fmt.Sprintf("%v", r)))
+			}
+			m.Run()
+		}
+	}()
+
 	for {
 		if m.Debugger.enabled {
 			m.Debug()
@@ -2081,6 +2095,15 @@ func (m *Machine) CheckEmpty() error {
 	}
 }
 
+func (m *Machine) buildPanicString(exceptions []Exception) string {
+	// Build exception string just as go, separated by \n\t.
+	exs := make([]string, len(exceptions))
+	for i, ex := range exceptions {
+		exs[i] = ex.Sprint(m)
+	}
+	return strings.Join(exs, "\n\t")
+}
+
 func (m *Machine) Panic(ex TypedValue) {
 	m.Exceptions = append(
 		m.Exceptions,

gnovm/pkg/gnolang/op_call.go

@@ -3,7 +3,6 @@ package gnolang
 import (
 	"fmt"
 	"reflect"
-	"strings"
 )
 
 func (m *Machine) doOpPrecall() {
@@ -422,12 +421,7 @@ func (m *Machine) doOpPanic2() {
 		// Keep panicking
 		last := m.PopUntilLastCallFrame()
 		if last == nil {
-			// Build exception string just as go, separated by \n\t.
-			exs := make([]string, len(m.Exceptions))
-			for i, ex := range m.Exceptions {
-				exs[i] = ex.Sprint(m)
-			}
-			panic(strings.Join(exs, "\n\t"))
+			panic(m.Exceptions)
 		}
 		m.PushOp(OpPanic2)
 		m.PushOp(OpReturnCallDefers) // XXX rename, not return?

gnovm/tests/files/recover13a.gno

@@ -0,0 +1,18 @@
+package main
+
+func p() {
+	defer func() {
+		if r := recover(); r != nil {
+			println(r)
+		}
+	}()
+	i := 0
+	i = 1 / i
+}
+
+func main() {
+	p()
+}
+
+// Output:
+// runtime error: integer divide by zero

gnovm/tests/files/recover13b.gno

@@ -0,0 +1,22 @@
+package main
+
+type s struct {
+	el func()
+}
+
+func p() {
+	var el *s
+	defer func() {
+		if r := recover(); r != nil {
+			println(r)
+		}
+	}()
+	el.el()
+}
+
+func main() {
+	p()
+}
+
+// Output:
+// interface conversion: gnolang.Value is nil, not gnolang.PointerValue