Transfer returned checksum values (#1719)

Checksums were missing from multipart uploads.

Author: klauspost

api-datatypes.go

@@ -87,6 +87,8 @@ type UploadInfo struct {
 	ExpirationRuleID string
 
 	// Verified checksum values, if any.
+	// Values are base64 (standard) encoded.
+	// For multipart objects this is a checksum of the checksum of each part.
 	ChecksumCRC32  string
 	ChecksumCRC32C string
 	ChecksumSHA1   string

api-put-object-multipart.go

@@ -448,5 +448,10 @@ func (c *Client) completeMultipartUpload(ctx context.Context, bucketName, object
 		Location:         completeMultipartUploadResult.Location,
 		Expiration:       expTime,
 		ExpirationRuleID: ruleID,
+
+		ChecksumSHA256: completeMultipartUploadResult.ChecksumSHA256,
+		ChecksumSHA1:   completeMultipartUploadResult.ChecksumSHA1,
+		ChecksumCRC32:  completeMultipartUploadResult.ChecksumCRC32,
+		ChecksumCRC32C: completeMultipartUploadResult.ChecksumCRC32C,
 	}, nil
 }