fix: harden economy recovery, shutdown concurrency, world validation, and inventory-loss paths

1 files changed, 6 insertions, 2 deletions

diff --git a/internal/casino/machine.go b/internal/casino/machine.go
index 0f137ec..844c5e9 100644
--- a/internal/casino/machine.go
+++ b/internal/casino/machine.go
@@ -228,8 +228,12 @@ func (m *Machine) finishSpin() []Event {
 	events := []Event{}
 	result := m.spin.Payout + m.payoutRemainder
 	// Checked conversion: a runaway profile or overflow must clamp at the
-	// economy cap instead of wrapping through a machine-sized int.
-	if result > MaxCredits || result != result || result < 0 {
+	// economy cap instead of wrapping through a machine-sized int. A NaN or
+	// negative result is a corrupt computation, not a jackpot: clamp it to
+	// zero (fail closed) rather than up to the economy ceiling (fail open).
+	if math.IsNaN(result) || result < 0 {
+		result = 0
+	} else if result > MaxCredits {
 		result = MaxCredits
 	}
 	credits := int(math.Floor(result))