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https://issues.apache.org/jira/browse/THRIFT-2429?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13960534#comment-13960534
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Randy Abernethy commented on THRIFT-2429:
-----------------------------------------
Hey Dave,
I think you're right we don't need the annotations. Here's the IDL and semantic
under consideration:
{code}
struct x {
1: optional i32 y = 5
}
{code}
* The optional modifier says: only serialize if set
* The default value says: never serialize if set to 5
The reader will set y to 5 and then read the stream, overwriting the 5 if a
value for y is provided by the stream. So the reader will always see some value
set for y at the end of the deserialization.
We are essentially giving the combination of optional requiredness and a
default value a clearly defined meaning in IDL across all languages. The result
is the interface optimization desired, the ability to elide default values
directly in Apache Thrift IDL.
-Randy
> Provide option to not write default values, rely on receiver default
> construction instead
> -----------------------------------------------------------------------------------------
>
> Key: THRIFT-2429
> URL: https://issues.apache.org/jira/browse/THRIFT-2429
> Project: Thrift
> Issue Type: Improvement
> Components: C++ - Compiler
> Affects Versions: 0.9.1
> Reporter: Chris Stylianou
> Assignee: Randy Abernethy
> Labels: default, optional, required
>
> Would there be any objections to a patch that does not write default values
> (essentially the same logic as the optional attributes). This obviously
> relies on the receiving application using the same IDL version to ensure the
> defaults used on object construction match the senders.
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