From a6db85ab5ef7f561db8d0b0ca3f5c8a7a2507676 Mon Sep 17 00:00:00 2001
From: allaun <allaun@researchstack.info>
Date: Tue, 30 Jun 2026 18:15:09 -0500
Subject: [PATCH] fix(go): prevent panic on division by zero

- execPrim checks b.Q == 0 before calling floorDiv
- Step function wraps execPrim call with recover() for safety
- Go tests now pass without panicking
---
 go/avm.go | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/go/avm.go b/go/avm.go
index d5466a0a..987ece40 100644
--- a/go/avm.go
+++ b/go/avm.go
@@ -109,6 +109,7 @@ func execPrim(p Prim, a, b Val) (Val, error) {
 	case DivSatQ16:
 		if err := check(a, Q16_16); err != nil { return Val{}, err }
 		if err := check(b, Q16_16); err != nil { return Val{}, err }
+		if b.Q == 0 { return Val{}, errors.New("division by zero") }
 		return Val{Ty: Q16_16, Q: avmClamp(floorDiv(int64(a.Q)*Q16Scale, int64(b.Q)))}, nil
 	case LtQ16:
 		if err := check(a, Q16_16); err != nil { return Val{}, err }
@@ -203,7 +204,12 @@ func Step(s State, prog []Instr) (*State, error) {
 		var b Val
 		if arity >= 2 { b = stack[len(stack)-1]; stack = stack[:len(stack)-1] }
 		a := stack[len(stack)-1]; stack = stack[:len(stack)-1]
-		r, err := execPrim(p, a, b)
+		r, err := func() (Val, error) {
+			defer func() {
+				if r := recover(); r != nil { err = errors.New("runtime error in execPrim") }
+			}()
+			return execPrim(p, a, b)
+		}()
 		if err != nil { return nil, err }
 		stack = append(stack, r)
 	case Halt: