unmarshal both LegalHold and ObjectLockLegalHold XML types (#11921)

Because of silly AWS S3 behavior we to handle both types.

fixes #11920

pkg/bucket/lifecycle/lifecycle.go

@@ -18,6 +18,7 @@ package lifecycle
 
 import (
 	"encoding/xml"
+	"fmt"
 	"io"
 	"strings"
 	"time"
@@ -71,7 +72,8 @@ func (lc *Lifecycle) UnmarshalXML(d *xml.Decoder, start xml.StartElement) (err e
 	switch start.Name.Local {
 	case "LifecycleConfiguration", "BucketLifecycleConfiguration":
 	default:
-		return errUnknownXMLTag
+		return xml.UnmarshalError(fmt.Sprintf("expected element type <LifecycleConfiguration>/<BucketLifecycleConfiguration> but have <%s>",
+			start.Name.Local))
 	}
 	for {
 		// Read tokens from the XML document in a stream.
@@ -93,7 +95,7 @@ func (lc *Lifecycle) UnmarshalXML(d *xml.Decoder, start xml.StartElement) (err e
 				}
 				lc.Rules = append(lc.Rules, r)
 			default:
-				return errUnknownXMLTag
+				return xml.UnmarshalError(fmt.Sprintf("expected element type <Rule> but have <%s>", se.Name.Local))
 			}
 		}
 	}

pkg/bucket/object/lock/lock.go

@@ -489,6 +489,41 @@ type ObjectLegalHold struct {
 	Status  LegalHoldStatus `xml:"Status,omitempty"`
 }
 
+// UnmarshalXML - decodes XML data.
+func (l *ObjectLegalHold) UnmarshalXML(d *xml.Decoder, start xml.StartElement) (err error) {
+	switch start.Name.Local {
+	case "LegalHold", "ObjectLockLegalHold":
+	default:
+		return xml.UnmarshalError(fmt.Sprintf("expected element type <LegalHold>/<ObjectLockLegalHold> but have <%s>",
+			start.Name.Local))
+	}
+	for {
+		// Read tokens from the XML document in a stream.
+		t, err := d.Token()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+
+		switch se := t.(type) {
+		case xml.StartElement:
+			switch se.Name.Local {
+			case "Status":
+				var st LegalHoldStatus
+				if err = d.DecodeElement(&st, &se); err != nil {
+					return err
+				}
+				l.Status = st
+			default:
+				return xml.UnmarshalError(fmt.Sprintf("expected element type <Status> but have <%s>", se.Name.Local))
+			}
+		}
+	}
+	return nil
+}
+
 // IsEmpty returns true if struct is empty
 func (l *ObjectLegalHold) IsEmpty() bool {
 	return !l.Status.Valid()

pkg/bucket/object/lock/lock_test.go

@@ -18,6 +18,7 @@ package lock
 
 import (
 	"encoding/xml"
+	"errors"
 	"fmt"
 	"net/http"
 	"reflect"
@@ -467,6 +468,23 @@ func TestParseObjectLegalHold(t *testing.T) {
 			expectedErr: nil,
 			expectErr:   false,
 		},
+		{
+			value:       `<?xml version="1.0" encoding="UTF-8"?><ObjectLockLegalHold xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Status>ON</Status></ObjectLockLegalHold>`,
+			expectedErr: nil,
+			expectErr:   false,
+		},
+		// invalid Status key
+		{
+			value:       `<?xml version="1.0" encoding="UTF-8"?><ObjectLockLegalHold xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><MyStatus>ON</MyStatus></ObjectLockLegalHold>`,
+			expectedErr: errors.New("expected element type <Status> but have <MyStatus>"),
+			expectErr:   true,
+		},
+		// invalid XML attr
+		{
+			value:       `<?xml version="1.0" encoding="UTF-8"?><UnknownLegalHold xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Status>ON</Status></UnknownLegalHold>`,
+			expectedErr: errors.New("expected element type <LegalHold>/<ObjectLockLegalHold> but have <UnknownLegalHold>"),
+			expectErr:   true,
+		},
 		{
 			value:       `<?xml version="1.0" encoding="UTF-8"?><LegalHold xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Status>On</Status></LegalHold>`,
 			expectedErr: ErrMalformedXML,