time: make Ticker.Reset(0) panic

Fixes #49315

Change-Id: I0887bad1059b25ae0749bfa1ed6ddccbecca7951
Reviewed-on: https://go-review.googlesource.com/c/go/+/361074
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Emmanuel Odeke <emmanuel@orijtech.com>

src/time/tick.go

@@ -48,8 +48,12 @@ func (t *Ticker) Stop() {
 }
 
 // Reset stops a ticker and resets its period to the specified duration.
-// The next tick will arrive after the new period elapses.
+// The next tick will arrive after the new period elapses. The duration d
+// must be greater than zero; if not, Reset will panic.
 func (t *Ticker) Reset(d Duration) {
+	if d <= 0 {
+		panic("non-positive interval for Ticker.Reset")
+	}
 	if t.r.f == nil {
 		panic("time: Reset called on uninitialized Ticker")
 	}

src/time/tick_test.go

@@ -134,6 +134,17 @@ func TestNewTickerLtZeroDuration(t *testing.T) {
 	NewTicker(-1)
 }
 
+// Test that Ticker.Reset panics when given a duration less than zero.
+func TestTickerResetLtZeroDuration(t *testing.T) {
+	defer func() {
+		if err := recover(); err == nil {
+			t.Errorf("Ticker.Reset(0) should have panicked")
+		}
+	}()
+	tk := NewTicker(Second)
+	tk.Reset(0)
+}
+
 func BenchmarkTicker(b *testing.B) {
 	benchmark(b, func(n int) {
 		ticker := NewTicker(Nanosecond)