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https://issues.apache.org/jira/browse/THRIFT-5803?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sylwester Lachiewicz resolved THRIFT-5803.
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Resolution: Not A Bug
Per the Thrift IDL specification (doc/specs/idl.md):
{quote}
*required*
- Write: Required fields are always written
- Read: Required fields are always read and are expected to be contained in the
input stream.
- Defaults values: are always written
If a required field is missing during read, the expected behaviour is to
indicate an unsuccessful read operation to the caller, e.g. by throwing an
exception or returning an error.
{quote}
Write validation and initialization behavior across language implementations:
- In Go and C++, required scalar fields are stored as direct values (not
pointers/nullable references) and carry the language default/zero-value (e.g.
empty string ""). When written, both Go and C++ always serialize the field to
the wire, satisfying the IDL requirement that "Required fields are always
written" and allowing peer deserializers to succeed.
- In Rust, required fields must be supplied to the constructor
(StructRequired::new(f_1: String)), preventing uninitialized required fields at
compile time.
- In Java, struct.validate() is called before write, throwing a
TProtocolException if a required field is null.
- In Python and Node.js, an unset required field defaults to None/null and is
silently omitted during serialization (writing an empty struct 00), which
causes peer receivers to throw a TProtocolException on read.
In Go, instantiating a struct with required fields without explicitly assigning
a value will serialize the Go zero-value for that type. This is consistent with
Go idioms and fulfills the Thrift wire requirement that required fields be
present on the wire.
Resolving as Not A Bug.
> Inconsistencies in Handling Default Values for Required Fields Across Thrift
> Implementations
> --------------------------------------------------------------------------------------------
>
> Key: THRIFT-5803
> URL: https://issues.apache.org/jira/browse/THRIFT-5803
> Project: Thrift
> Issue Type: Bug
> Components: Go - Compiler
> Affects Versions: 0.19.0, 0.20.0
> Reporter: Team_RPCtester
> Priority: Major
>
> Hi,
> We discover an inconsistent behavior with respect to default values for
> required string fields. Specifically, in Go, a required string field is
> automatically initialized to an empty string if not explicitly set, whereas
> other languages do not automatically initialize this field. This
> inconsistency can be illustrated with the following example:
> Thrift Definition:
> {code:java}
> namespace go commonResource
> struct StructClass_0 {
> 1: required string f_1,
> }
> service DataService {
> StructClass_0 Method_1(1: StructClass_0 agr_method_1)
> }
> {code}
> Go client side,
> {code:java}
> agr_method_1_0 := commonResource.NewStructClass_0()
> fmt.Println(agr_method_1_0)
> // method_1_re_agr_method_1_0: StructClass_0({F_1:})
> {code}
> python client side
> {code:java}
> agr_method_1 = StructClass_0()
> print(agr_method_1)
> # StructClass_0(f_1=None)
> {code}
> nodejs client side
> {code:java}
> arg_Method_1 = new ttypes.StructClass_0();
> console.log(arg_Method_1);
> // { f_1: null }
> {code}
> GO server side
> {code:java}
> func (d DataServiceHandler) Method_1(ctx context.Context, agr_method_1
> *commonResource.StructClass_0) (re_agr_method_1
> *commonResource.StructClass_0, _err error) {
> re_agr_method_1 = agr_method_1
> return re_agr_method_1, nil
> }
> {code}
> *Behavior Observed:*
> * On the Go client side, if agr_method_1_0 is sent with an uninitialized
> f_1, Go automatically sets f_1 to an empty string. The server receives this
> empty string and processes it accordingly.
> * On the Node.js client side, if arg_Method_1 is sent with an uninitialized
> f_1, Node.js client reports an error: "Required field f_1 is unset!" and does
> not allow the call to proceed.
> * On the Python client side, if agr_method_1 is sent with f_1 as null, the
> Go server reports: "*commonResource.StructClass_0 error reading struct:
> Required field F_1 is not, the Nodejs server will prompt “"Required field f_1
> is unset!"”, the Python server will return what it receives.
> Can you help check this issue.
> Thank you.
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