use error struct directly

Author: Fs02

add_error.go

@@ -5,28 +5,23 @@ type Error struct {
 Message string `json:"message"`
 Field string `json:"field,omitempty"`
 Code int `json:"code,omitempty"`
-// Err error `json:"-"` TODO: Unwrap
+Err error `json:"-"`
 }
 
 // Error prints error message.
 func (e Error) Error() string {
 return e.Message
 }
 
-// NewError creates an error with field and message.
-func NewError(message string, field string) error {
-return NewErrorWithCode(message, field, 0)
-}
-
-// NewErrorWithCode creates an error with code.
-func NewErrorWithCode(message string, field string, code int) error {
-return Error{message, field, code}
+// Unwrap internal error.
+func (e Error) Unwrap() error {
+return e.Err
 }
 
 // AddError adds an error to changeset.
 //	ch := changeset.Cast(user, params, fields)
 //	changeset.AddError(ch, "field", "error")
 //	ch.Errors() // []errors.Error{{Field: "field", Message: "error"}}
 func AddError(ch *Changeset, field string, message string) {
-ch.errors = append(ch.errors, NewError(message, field))
+ch.errors = append(ch.errors, Error{Message: message, Field: field})
 }

constraint.go

@@ -35,7 +35,12 @@ func (constraints Constraints) GetError(err rel.ConstraintError) error {
 continue
 }
 
-return NewErrorWithCode(c.Message, c.Field, c.Code)
+return Error{
+Message: c.Message,
+Field: c.Field,
+Code: c.Code,
+Err: err,
+}
 }
 }
 

constraint_test.go

@@ -21,17 +21,17 @@ func TestConstraint_GetError(t *testing.T) {
 {
 name: "unique",
 err: rel.ConstraintError{Key: "slug_unique_index", Type: rel.UniqueConstraint},
-expected: NewError("slug has already been taken", "slug"),
+expected: Error{Message: "slug has already been taken", Field: "slug", Err: rel.ConstraintError{Key: "slug_unique_index", Type: rel.UniqueConstraint}},
 },
 {
 name: "fk",
 err: rel.ConstraintError{Key: "user_id_ibfk1", Type: rel.ForeignKeyConstraint},
-expected: NewError("does not exist", "user_id"),
+expected: Error{Message: "does not exist", Field: "user_id", Err: rel.ConstraintError{Key: "user_id_ibfk1", Type: rel.ForeignKeyConstraint}},
 },
 {
 name: "check",
 err: rel.ConstraintError{Key: "state_check", Type: rel.CheckConstraint},
-expected: NewError("state is invalid", "state"),
+expected: Error{Message: "state is invalid", Field: "state", Err: rel.ConstraintError{Key: "state_check", Type: rel.CheckConstraint}},
 },
 {
 name: "undefined unique",