fix: route创建时的校验

apps/mtm/serializers.py

@@ -150,7 +150,8 @@ class RouteSerializer(CustomModelSerializer):
 
     def create(self, validated_data):
         process = validated_data['process']
-        if process and Route.objects.filter(material=validated_data['material'], process=process).exists():
+        material = validated_data.get('material', None)
+        if material and process and Route.objects.filter(material=material, process=process).exists():
             raise ValidationError('已选择该工序')
         with transaction.atomic():
             instance = super().create(validated_data)