stop overriding max backoff when none is set (#189)

retry/retry.go

@@ -124,7 +124,8 @@ func WithMaxAttempts(maxAttempts int) Option {
 // WithInitialBackoff sets initial backoff.
 //
 // If initial backoff option is not used, then default value of 50 milliseconds is used.
-// If initial backoff is larger than max backoff, it takes precedence.
+// If initial backoff is larger than max backoff and the max backoff is nonzero, the initial backoff will be
+// used as the max.
 func WithInitialBackoff(initialBackoff time.Duration) Option {
 	return func(o *options) {
 		o.initialBackoff = initialBackoff
@@ -181,8 +182,10 @@ func Start(ctx context.Context, opts ...Option) Retrier {
 	for _, option := range opts {
 		option(&r.options)
 	}
-	// If initial backoff is larger than max backoff, it takes precedence.
-	r.options.maxBackoff = max(r.options.maxBackoff, r.options.initialBackoff)
+	// If initial backoff is larger than max backoff and the max backoff is set, initial takes precedence.
+	if r.options.maxBackoff != 0 {
+		r.options.maxBackoff = max(r.options.maxBackoff, r.options.initialBackoff)
+	}
 	r.Reset()
 	return r
 }

retry/retry_test.go

@@ -97,6 +97,27 @@ func TestRetrier_Next_WithInitialBackoffLargerThanMax(t *testing.T) {
 	}
 }
 
+func TestRetrier_Next_WithInitialBackoffLargerThanMaxAndMaxNotSet(t *testing.T) {
+	const initialBackoff = time.Second * 5
+	const maxBackoff = 0
+	const multiplier = 2
+
+	options := []Option{
+		WithInitialBackoff(initialBackoff),
+		WithMaxBackoff(maxBackoff),
+		WithMultiplier(multiplier),
+		WithMaxAttempts(11),
+		WithRandomizationFactor(0),
+	}
+
+	r := Start(context.Background(), options...).(*retrier)
+	r.currentAttempt = 1
+	d := r.retryIn()
+	if d != initialBackoff*multiplier {
+		t.Fatalf("expected second attempt to increase backoff: %s vs %s", d, initialBackoff*multiplier)
+	}
+}
+
 func TestRetrier_Next_WithMaxAttempts(t *testing.T) {
 	const maxAttempts = 2