fixes

✅ Include VersionId in multipart upload completion responses when versioning is enabled
✅ Block retention mode changes (GOVERNANCE ↔ COMPLIANCE) without bypass permissions
✅ Handle all object lock validation errors consistently with proper error codes
✅ Pass the remaining object lock tests

weed/s3api/filer_multipart.go

@@ -247,13 +247,72 @@ func (s3a *S3ApiServer) completeMultipartUpload(input *s3.CompleteMultipartUploa
 		return nil, s3err.ErrInternalError
 	}
 
-	output = &CompleteMultipartUploadResult{
-		CompleteMultipartUploadOutput: s3.CompleteMultipartUploadOutput{
-			Location: aws.String(fmt.Sprintf("http://%s%s/%s", s3a.option.Filer.ToHttpAddress(), urlEscapeObject(dirName), urlPathEscape(entryName))),
-			Bucket:   input.Bucket,
-			ETag:     aws.String("\"" + filer.ETagChunks(finalParts) + "\""),
-			Key:      objectKey(input.Key),
-		},
+	// Check if versioning is enabled for this bucket
+	versioningEnabled, vErr := s3a.isVersioningEnabled(*input.Bucket)
+	if vErr == nil && versioningEnabled {
+		// For versioned buckets, create a version and return the version ID
+		versionId := generateVersionId()
+		versionFileName := s3a.getVersionFileName(versionId)
+		versionDir := dirName + "/" + entryName + ".versions"
+
+		// Move the completed object to the versions directory
+		err = s3a.mkFile(versionDir, versionFileName, finalParts, func(versionEntry *filer_pb.Entry) {
+			if versionEntry.Extended == nil {
+				versionEntry.Extended = make(map[string][]byte)
+			}
+			versionEntry.Extended[s3_constants.ExtVersionIdKey] = []byte(versionId)
+			versionEntry.Extended[s3_constants.SeaweedFSUploadId] = []byte(*input.UploadId)
+			for k, v := range pentry.Extended {
+				if k != "key" {
+					versionEntry.Extended[k] = v
+				}
+			}
+			if pentry.Attributes.Mime != "" {
+				versionEntry.Attributes.Mime = pentry.Attributes.Mime
+			} else if mime != "" {
+				versionEntry.Attributes.Mime = mime
+			}
+			versionEntry.Attributes.FileSize = uint64(offset)
+		})
+
+		if err != nil {
+			glog.Errorf("completeMultipartUpload: failed to create version %s: %v", versionId, err)
+			return nil, s3err.ErrInternalError
+		}
+
+		// Create a delete marker for the main object (latest version)
+		err = s3a.mkFile(dirName, entryName, nil, func(mainEntry *filer_pb.Entry) {
+			if mainEntry.Extended == nil {
+				mainEntry.Extended = make(map[string][]byte)
+			}
+			mainEntry.Extended[s3_constants.ExtVersionIdKey] = []byte(versionId)
+			mainEntry.Extended[s3_constants.ExtDeleteMarkerKey] = []byte("false") // This is the latest version, not a delete marker
+		})
+
+		if err != nil {
+			glog.Errorf("completeMultipartUpload: failed to update main entry: %v", err)
+			return nil, s3err.ErrInternalError
+		}
+
+		output = &CompleteMultipartUploadResult{
+			CompleteMultipartUploadOutput: s3.CompleteMultipartUploadOutput{
+				Location:  aws.String(fmt.Sprintf("http://%s%s/%s", s3a.option.Filer.ToHttpAddress(), urlEscapeObject(dirName), urlPathEscape(entryName))),
+				Bucket:    input.Bucket,
+				ETag:      aws.String("\"" + filer.ETagChunks(finalParts) + "\""),
+				Key:       objectKey(input.Key),
+				VersionId: aws.String(versionId),
+			},
+		}
+	} else {
+		// For non-versioned buckets, return response without VersionId
+		output = &CompleteMultipartUploadResult{
+			CompleteMultipartUploadOutput: s3.CompleteMultipartUploadOutput{
+				Location: aws.String(fmt.Sprintf("http://%s%s/%s", s3a.option.Filer.ToHttpAddress(), urlEscapeObject(dirName), urlPathEscape(entryName))),
+				Bucket:   input.Bucket,
+				ETag:     aws.String("\"" + filer.ETagChunks(finalParts) + "\""),
+				Key:      objectKey(input.Key),
+			},
+		}
 	}
 
 	for _, deleteEntry := range deleteEntries {

weed/s3api/s3api_object_retention.go

@@ -348,6 +348,20 @@ func (s3a *S3ApiServer) setObjectRetention(bucket, object, versionId string, ret
 	// Check if object is already under retention
 	if entry.Extended != nil {
 		if existingMode, exists := entry.Extended[s3_constants.ExtObjectLockModeKey]; exists {
+			// Check if attempting to change retention mode
+			if retention.Mode != "" && string(existingMode) != retention.Mode {
+				// Attempting to change retention mode
+				if string(existingMode) == s3_constants.RetentionModeCompliance {
+					// Cannot change compliance mode retention without bypass
+					return ErrComplianceModeActive
+				}
+
+				if string(existingMode) == s3_constants.RetentionModeGovernance && !bypassGovernance {
+					// Cannot change governance mode retention without bypass
+					return ErrGovernanceModeActive
+				}
+			}
+
 			if existingDateBytes, dateExists := entry.Extended[s3_constants.ExtRetentionUntilDateKey]; dateExists {
 				if timestamp, err := strconv.ParseInt(string(existingDateBytes), 10, 64); err == nil {
 					existingDate := time.Unix(timestamp, 0)