From ca6a92bb845cb7325655ef4cf1891dec9fde4bcd Mon Sep 17 00:00:00 2001
From: niksis02 <sisnikoyan@gmail.com>
Date: Thu, 18 Sep 2025 16:09:02 +0400
Subject: [PATCH] fix: changes empty mp parts error on CompleteMultipartUpload

Fixes #1328

If `CompleteMultipartUpload` is attempted with empty `Parts` list, the gateway used to return `InvalidRequest`. Now it's changed to `MalformedXML`.
---
 s3api/controllers/object-post.go      | 2 +-
 s3api/controllers/object-post_test.go | 2 +-
 s3err/s3err.go                        | 6 ------
 tests/integration/tests.go            | 2 +-
 4 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/s3api/controllers/object-post.go b/s3api/controllers/object-post.go
index 4f4df45..3dbba5c 100644
--- a/s3api/controllers/object-post.go
+++ b/s3api/controllers/object-post.go
@@ -278,7 +278,7 @@ func (c S3ApiController) CompleteMultipartUpload(ctx *fiber.Ctx) (*Response, err
 			MetaOpts: &MetaOptions{
 				BucketOwner: parsedAcl.Owner,
 			},
-		}, s3err.GetAPIError(s3err.ErrEmptyParts)
+		}, s3err.GetAPIError(s3err.ErrMalformedXML)
 	}
 
 	var mpuObjectSize *int64
diff --git a/s3api/controllers/object-post_test.go b/s3api/controllers/object-post_test.go
index cf07ec7..57fcff8 100644
--- a/s3api/controllers/object-post_test.go
+++ b/s3api/controllers/object-post_test.go
@@ -404,7 +404,7 @@ func TestS3ApiController_CompleteMultipartUpload(t *testing.T) {
 						BucketOwner: "root",
 					},
 				},
-				err: s3err.GetAPIError(s3err.ErrEmptyParts),
+				err: s3err.GetAPIError(s3err.ErrMalformedXML),
 			},
 		},
 		{
diff --git a/s3err/s3err.go b/s3err/s3err.go
index 85fb111..627069c 100644
--- a/s3err/s3err.go
+++ b/s3err/s3err.go
@@ -82,7 +82,6 @@ const (
 	ErrInvalidPartNumberMarker
 	ErrInvalidObjectAttributes
 	ErrInvalidPart
-	ErrEmptyParts
 	ErrInvalidPartNumber
 	ErrInvalidPartOrder
 	ErrInvalidCompleteMpPartNumber
@@ -311,11 +310,6 @@ var errorCodeResponse = map[ErrorCode]APIError{
 		Description:    "One or more of the specified parts could not be found.  The part may not have been uploaded, or the specified entity tag may not match the part's entity tag.",
 		HTTPStatusCode: http.StatusBadRequest,
 	},
-	ErrEmptyParts: {
-		Code:           "InvalidRequest",
-		Description:    "You must specify at least one part",
-		HTTPStatusCode: http.StatusBadRequest,
-	},
 	ErrInvalidPartNumber: {
 		Code:           "InvalidArgument",
 		Description:    "Part number must be an integer between 1 and 10000, inclusive.",
diff --git a/tests/integration/tests.go b/tests/integration/tests.go
index 9c7e9aa..cfbdb36 100644
--- a/tests/integration/tests.go
+++ b/tests/integration/tests.go
@@ -13012,7 +13012,7 @@ func CompleteMultipartUpload_empty_parts(s *S3Conf) error {
 			},
 		})
 		cancel()
-		if err := checkApiErr(err, s3err.GetAPIError(s3err.ErrEmptyParts)); err != nil {
+		if err := checkApiErr(err, s3err.GetAPIError(s3err.ErrMalformedXML)); err != nil {
 			return err
 		}