[jira] [Commented] (THRIFT-1528) Inconsistency in optional fields between Java/C# and python

["James Haggerty (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/THRIFT-1528?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13865039#comment-13865039 ] 

James Haggerty commented on THRIFT-1528:
----------------------------------------

As Josh mentioned, there are significant advantages to not serialising default values.

Say you have a large Struct with a lot of boolean options in it, but 90% of the time those options don't move from their defaults (normally False). To get around this issue, you could try to implement booleans defaulting to False by using optional without a default (i.e. counting !isset/null/None as false). But abusing things like this means you can't distinguish between fields that are null because they are not filled in and fields that are null because that represents false... which is a pain when you're custom encoding the struct as JSON for the end user.

IMO it doesn't make much sense to have 'optional with default' unless this behaviour is supported.

> Inconsistency in optional fields between Java/C# and python
> -----------------------------------------------------------
>
>                 Key: THRIFT-1528
>                 URL: https://issues.apache.org/jira/browse/THRIFT-1528
>             Project: Thrift
>          Issue Type: Bug
>          Components: Python - Compiler
>    Affects Versions: 0.8
>            Reporter: Stefan Gmeiner
>             Fix For: 1.0
>
>
> If a struct contains optional fields with default values the generated python code serialize differently than Java or C# code.
> In Java or C# optional fields are only serialized if a field was set by the client. If not the field is omited during serialization. This is possible because C#/Java maintains for each field a 'isset'-boolean which records if a field was set or not.
> However the generated python code does not have such a 'isset'-structure. It writes every field which is not equal None. As the constructor initialize the optional fields with their default value, these fields are written whether they are set or not.



--
This message was sent by Atlassian JIRA
(v6.1.5#6160)