Removed defer/panic. #503

1 files changed, 4 insertions, 6 deletions

diff --git a/core/vm/stack.go b/core/vm/stack.go
index 1e093476b..168637708 100644
--- a/core/vm/stack.go
+++ b/core/vm/stack.go
@@ -17,10 +17,7 @@ type stack struct {
 }
 
 func (st *stack) push(d *big.Int) {
-	if len(st.data) == maxStack {
-		panic(fmt.Sprintf("stack limit reached (%d)", maxStack))
-	}
-
+	// NOTE push limit (1024) is checked in baseCheck
 	stackItem := new(big.Int).Set(d)
 	if len(st.data) > st.ptr {
 		st.data[st.ptr] = stackItem
@@ -52,10 +49,11 @@ func (st *stack) peek() *big.Int {
 	return st.data[st.len()-1]
 }
 
-func (st *stack) require(n int) {
+func (st *stack) require(n int) error {
 	if st.len() < n {
-		panic(fmt.Sprintf("stack underflow (%d <=> %d)", len(st.data), n))
+		return fmt.Errorf("stack underflow (%d <=> %d)", len(st.data), n)
 	}
+	return nil
 }
 
 func (st *stack) Print() {