perf: skip retry sleep if context deadline is too short

retry.go

@@ -72,14 +72,14 @@ func (r *retryer) WaitForRetry(ctx context.Context, duration time.Duration) {
 	}
 }
 
-func (r *retryer) WaitOrSkipRetry(
-	ctx context.Context, attempts int, cmd Completed, err error,
-) bool {
-	if delay := r.RetryDelay(attempts, cmd, err); delay == 0 {
+func (r *retryer) WaitOrSkipRetry(ctx context.Context, attempts int, cmd Completed, err error) bool {
+	delay := r.RetryDelay(attempts, cmd, err)
+	if delay == 0 {
 		runtime.Gosched()
 		return true
-	} else if delay > 0 {
-		if dl, ok := ctx.Deadline(); !ok || time.Until(dl) > delay {
+	}
+	if delay > 0 {
+		if dl, ok := ctx.Deadline(); !ok || time.Until(dl) > (delay+(100*time.Microsecond)) {
 			r.WaitForRetry(ctx, delay)
 			return true
 		}

retryer_custom_test.go

@@ -0,0 +1,27 @@
+package rueidis
+
+import (
+	"context"
+	"testing"
+	"time"
+)
+
+func TestWaitOrSkipRetry_DeadlineBuffer(t *testing.T) {
+	r := newRetryer(func(attempts int, cmd Completed, err error) time.Duration {
+		return 10 * time.Millisecond // This will force a 10ms delay.
+	})
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Millisecond)
+	defer cancel()
+
+	start := time.Now() // Returns false immediately b/c 5ms < 10ms + buffer inherently
+	retriable := r.WaitOrSkipRetry(ctx, 1, Completed{}, nil)
+	duration := time.Since(start)
+
+	if retriable {
+		t.Errorf("Expected retriable to be false when deadline is shorter than delay")
+	}
+	if duration > 2*time.Millisecond {
+		t.Errorf("Expected function to return immediately, but it took %v", duration)
+	}
+}