fix: hardcode max vm cycles in keeper

gnovm/pkg/gnolang/machine.go

@@ -75,6 +75,7 @@ type MachineOptions struct {
 	Alloc         *Allocator // or see MaxAllocBytes.
 	MaxAllocBytes int64      // or 0 for no limit.
 	MaxCycles     int64      // or 0 for no limit.
+	IsTest        bool
 }
 
 // the machine constructor gets spammed
@@ -99,6 +100,10 @@ func NewMachineWithOptions(opts MachineOptions) *Machine {
 	checkTypes := opts.CheckTypes
 	readOnly := opts.ReadOnly
 	maxCycles := opts.MaxCycles
+	if !opts.IsTest && maxCycles == 0 {
+		// Never allow an infinite number of cycles.
+		maxCycles = 10_000_000
+	}
 	output := opts.Output
 	if output == nil {
 		output = os.Stdout
@@ -654,6 +659,13 @@ func (m *Machine) RunFunc(fn Name) {
 func (m *Machine) RunMain() {
 	defer func() {
 		if r := recover(); r != nil {
+			// This is likely due to an infinite loop or recursion.
+			// Don't tryp to print out the machine state as it may
+			// take a very long time or never finish.
+			if v, ok := r.(cpuCyclePanic); ok {
+				panic(v.String())
+			}
+
 			fmt.Printf("Machine.RunMain() panic: %v\n%s\n",
 				r, m.String())
 			panic(r)
@@ -949,10 +961,16 @@ const (
 //----------------------------------------
 // "CPU" steps.
 
+type cpuCyclePanic struct{}
+
+func (p cpuCyclePanic) String() string {
+	return "CPU cycle overrun"
+}
+
 func (m *Machine) incrCPU(cycles int64) {
 	m.Cycles += cycles
 	if m.MaxCycles != 0 && m.Cycles > m.MaxCycles {
-		panic("CPU cycle overrun")
+		panic(cpuCyclePanic{})
 	}
 }
 

gnovm/tests/file.go

@@ -57,6 +57,7 @@ func testMachineCustom(store gno.Store, pkgPath string, stdout io.Writer, maxAll
 		Store:         store,
 		Context:       ctx,
 		MaxAllocBytes: maxAlloc,
+		IsTest:        true,
 	})
 	return m
 }

gnovm/tests/files/cycles.gno

@@ -0,0 +1,12 @@
+package main
+
+func main() {
+	recurse()
+}
+
+func recurse() int {
+	return recurse()
+}
+
+// Error:
+// CPU cycle overrun

gnovm/tests/machine_test.go

@@ -47,6 +47,7 @@ func TestMachineTestMemPackage(t *testing.T) {
 							Output:  os.Stdout,
 							Store:   store,
 							Context: nil,
+							IsTest:  true,
 						})
 						memPkg := gno.ReadMemPackage(tt.path, "test")