Renames tfresource.ExpectSingleResult to tfresource.AssertSingleResult and returns the value

Author: gdavison

internal/service/cognitoidp/find.go

@@ -112,11 +112,12 @@ func FindCognitoUserPoolClientByName(ctx context.Context, conn *cognitoidentityp
 		return nil, err
 	}
 
-	if err := tfresource.ExpectSingleResult(clientDescs); err != nil {
+	client, err := tfresource.AssertSingleResult(clientDescs)
+	if err != nil {
 		return nil, err
 	}
 
-	return FindCognitoUserPoolClientByID(ctx, conn, userPoolId, aws.StringValue(clientDescs[0].ClientId))
+	return FindCognitoUserPoolClientByID(ctx, conn, userPoolId, aws.StringValue(client.ClientId))
 }
 
 type cognitoUserPoolClientDescriptionNameFilter func(string) (bool, error)

internal/tfresource/not_found_error.go

@@ -92,13 +92,13 @@ func SingularDataSourceFindError(resourceType string, err error) error {
 	return fmt.Errorf("reading %s: %w", resourceType, err)
 }
 
-func ExpectSingleResult[T any](a []*T) error {
+func AssertSingleResult[T any](a []*T) (*T, error) {
 	if l := len(a); l == 0 {
-		return NewEmptyResultError(nil)
+		return nil, NewEmptyResultError(nil)
 	} else if l > 1 {
-		return NewTooManyResultsError(l, nil)
+		return nil, NewTooManyResultsError(l, nil)
 	} else if a[0] == nil {
-		return NewEmptyResultError(nil)
+		return nil, NewEmptyResultError(nil)
 	}
-	return nil
+	return a[0], nil
 }