Fix Error Code for ObjectTagging Parsing (#8971)

Also add Mint tests

pkg/bucket/object/tagging/error.go

@@ -23,13 +23,14 @@ import (
 // Error is the generic type for any error happening during tag
 // parsing.
 type Error struct {
-	err error
+	err  error
+	code string
 }
 
 // Errorf - formats according to a format specifier and returns
 // the string as a value that satisfies error of type tagging.Error
-func Errorf(format string, a ...interface{}) error {
-	return Error{err: fmt.Errorf(format, a...)}
+func Errorf(format, code string, a ...interface{}) error {
+	return Error{err: fmt.Errorf(format, a...), code: code}
 }
 
 // Unwrap the internal error.
@@ -42,3 +43,11 @@ func (e Error) Error() string {
 	}
 	return e.err.Error()
 }
+
+// Code returns appropriate error code.
+func (e Error) Code() string {
+	if e.code == "" {
+		return "BadRequest"
+	}
+	return e.code
+}

pkg/bucket/object/tagging/tagging.go

@@ -33,10 +33,10 @@ const (
 
 // errors returned by tagging package
 var (
-	ErrTooManyTags     = Errorf("Cannot have more than 10 object tags")
-	ErrInvalidTagKey   = Errorf("The TagKey you have provided is invalid")
-	ErrInvalidTagValue = Errorf("The TagValue you have provided is invalid")
-	ErrInvalidTag      = Errorf("Cannot provide multiple Tags with the same key")
+	ErrTooManyTags     = Errorf("Object tags cannot be greater than 10", "BadRequest")
+	ErrInvalidTagKey   = Errorf("The TagKey you have provided is invalid", "InvalidTag")
+	ErrInvalidTagValue = Errorf("The TagValue you have provided is invalid", "InvalidTag")
+	ErrInvalidTag      = Errorf("Cannot provide multiple Tags with the same key", "InvalidTag")
 )
 
 // Tagging - object tagging interface
@@ -51,15 +51,15 @@ func (t Tagging) Validate() error {
 	if len(t.TagSet.Tags) > maxTags {
 		return ErrTooManyTags
 	}
-	if t.TagSet.ContainsDuplicateTag() {
-		return ErrInvalidTag
-	}
 	// Validate all the rules in the tagging config
 	for _, ts := range t.TagSet.Tags {
 		if err := ts.Validate(); err != nil {
 			return err
 		}
 	}
+	if t.TagSet.ContainsDuplicateTag() {
+		return ErrInvalidTag
+	}
 	return nil
 }