Fix State.stackIndex for negative indices

zombiezen · zombiezen · commit e7d59e905dda · 2024-12-09T11:22:42.000-08:00
diff --git a/internal/mylua/lua.go b/internal/mylua/lua.go
@@ -130,7 +130,7 @@ func (l *State) stackIndex(idx int) (int, error) {
 		if idx < -l.Top() {
 			return -1, fmt.Errorf("invalid index %d (top = %d)", idx, l.Top())
 		}
-		return l.frame().registerStart() - idx - 1, nil
+		return len(l.stack) + idx, nil
 	}
 	i := l.frame().registerStart() + idx - 1
 	if i >= cap(l.stack) {

Original file line number	Diff line number	Diff line change
`@@ -130,7 +130,7 @@ func (l *State) stackIndex(idx int) (int, error) {`
`130`	`130`	`if idx < -l.Top() {`
`131`	`131`	`return -1, fmt.Errorf("invalid index %d (top = %d)", idx, l.Top())`
`132`	`132`	`}`
`133`		`- return l.frame().registerStart() - idx - 1, nil`
	`133`	`+ return len(l.stack) + idx, nil`
`134`	`134`	`}`
`135`	`135`	`i := l.frame().registerStart() + idx - 1`
`136`	`136`	`if i >= cap(l.stack) {`