feat: support uuid.UUID in mapping (#2537)

core/mapping/unmarshaler.go

@@ -1,6 +1,7 @@
 package mapping
 
 import (
+	"encoding"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -318,6 +319,28 @@ func (u *Unmarshaler) processFieldStructWithMap(field reflect.StructField, value
 	return nil
 }
 
+func (u *Unmarshaler) processFieldTextUnmarshaler(field reflect.StructField, value reflect.Value,
+	mapValue interface{}) (bool, error) {
+	var tval encoding.TextUnmarshaler
+	var ok bool
+
+	if field.Type.Kind() == reflect.Ptr {
+		tval, ok = value.Interface().(encoding.TextUnmarshaler)
+	} else {
+		tval, ok = value.Addr().Interface().(encoding.TextUnmarshaler)
+	}
+	if ok {
+		switch mv := mapValue.(type) {
+		case string:
+			return true, tval.UnmarshalText([]byte(mv))
+		case []byte:
+			return true, tval.UnmarshalText(mv)
+		}
+	}
+
+	return false, nil
+}
+
 func (u *Unmarshaler) processNamedField(field reflect.StructField, value reflect.Value,
 	m Valuer, fullName string) error {
 	key, opts, err := u.parseOptionsWithContext(field, m, fullName)
@@ -348,8 +371,16 @@ func (u *Unmarshaler) processNamedFieldWithValue(field reflect.StructField, valu
 		return fmt.Errorf("field %s mustn't be nil", key)
 	}
 
+	if !value.CanSet() {
+		return fmt.Errorf("field %s is not settable", key)
+	}
+
 	maybeNewValue(field, value)
 
+	if yes, err := u.processFieldTextUnmarshaler(field, value, mapValue); yes {
+		return err
+	}
+
 	fieldKind := Deref(field.Type).Kind()
 	switch fieldKind {
 	case reflect.Array, reflect.Map, reflect.Slice, reflect.Struct: