retry.Attempts(0) causes retry to not return error on context timeout

[merusso]

Problem

When using retry.Option retry.Attempts(0), this changes retry's error handling behavior for a timed-out context. retry.Do returns a nil response instead of an error.

Tested versions with this issue:

• v4.3.1
• v4.3.2

Expected

When a context times out, retry.Do should terminate and return an error.

Actual

When using retry.Attempts(0) and a context times out, retry.Do returns with no error, implying success. When retry.Attempts is not set or is set to another value, retry.Do returns an error.

Workaround

Set retry.Attempts to a large number, e.g. retry.Attempts(99999999)

Test

func TestRetry_timeoutWithAttempts0(t *testing.T) {
	g := NewGomegaWithT(t)

	// Test 1, default retry.Attempts (=10)
	// Passes

	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
	defer cancel()

	err := retry.Do(func() error {
		return errors.New("simulated error")
	}, retry.Context(ctx))
	g.Expect(err).To(HaveOccurred())

	ctx, cancel = context.WithTimeout(context.Background(), 1*time.Second)
	defer cancel()

	// Test 2, retry.Attempts(0)
	// Fails

	err = retry.Do(func() error {
		return errors.New("simulated error")
	}, retry.Context(ctx), retry.Attempts(0))
	g.Expect(err).To(HaveOccurred())
}