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https://issues.apache.org/jira/browse/THRIFT-529?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12754348#action_12754348
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Nathan Marz commented on THRIFT-529:
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I'm not a fan of "..., if and only if there are both optional and non-optional
fields in the struct. Otherwise, it only creates the standard constructors.".
An all optional field struct has just as brittle constructors as one with both
required fields and optional fields. I don't have any problems with an
all-optional field struct having only the empty constructor. Creating
constructors only for required fields gives the nice property that adding an
optional field will never cause the code to break.
David, if constructors only contain required fields does that resolve your
issue?
> Change generated constructors so that application code evolves better
> ---------------------------------------------------------------------
>
> Key: THRIFT-529
> URL: https://issues.apache.org/jira/browse/THRIFT-529
> Project: Thrift
> Issue Type: Improvement
> Components: Compiler (Java)
> Reporter: Nathan Marz
> Assignee: Bryan Duxbury
> Priority: Minor
> Fix For: 0.2
>
> Attachments: thrift-529.patch
>
>
> The constructors generated by the Java compiler encourage code that breaks
> when the thrift definition changes. For example, it is common to add an
> optional field to a pre-existing schema, like:
> struct Activity {
> 1: required i32 id;
> 2: required i32 type;
> 3: optional i64 timestamp; //newly added
> }
> Any code that used the Activity(int, int) constructor will now break.
> One option to address this problem is to only generate empty constructors.
> However, this makes it cumbersome to create new objects as a line of code is
> needed to instantiate each field. A second option is to generate constructors
> only for required fields. For example, to create an Activity with a
> timestamp, the user would need to do the following:
> Activity a = new Acitivity(3,4);
> a.set_timestamp(timestamp);
> This gracefully handles the addition of optional fields. For the case of
> adding a new required field, the constructors would break. Arguably this is
> desired behavior since all the code would need to be updated anyway, and this
> way you would be getting compile errors instead of runtime validation errors.
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