fix getter func for attempt results to return bool instead of an err

aws/retry/metadata.go

@@ -1,7 +1,6 @@
 package retry
 
 import (
-	"fmt"
 	"github.com/aws/smithy-go/middleware"
 )
 
@@ -11,13 +10,9 @@ type attemptResultsKey struct {
 }
 
 // GetAttemptResults retrieves attempts results from middleware metadata.
-func GetAttemptResults(metadata middleware.Metadata) (AttemptResults, error) {
+func GetAttemptResults(metadata middleware.Metadata) (AttemptResults, bool) {
 	m, ok := metadata.Get(attemptResultsKey{}).(AttemptResults)
-	if !ok {
-		return AttemptResults{},
-			fmt.Errorf("failed to fetch attempt results from metadata")
-	}
-	return m, nil
+	return m, ok
 }
 
 // AttemptResults represents struct containing metadata returned by all request attempts.

aws/retry/middleware_test.go

@@ -395,9 +395,9 @@ func TestAttemptMiddleware(t *testing.T) {
 				t.Error(diff)
 			}
 
-			attemptResults, err := GetAttemptResults(metadata)
-			if err != nil {
-				t.Fatalf("expected no error, got %v", err)
+			attemptResults, ok := GetAttemptResults(metadata)
+			if !ok {
+				t.Fatalf("expected metadata to contain attempt results, got none")
 			}
 			if e, a := tt.ExpectResults, attemptResults; !reflect.DeepEqual(e, a) {
 				t.Fatalf("expected %v, got %v", e, a)