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Jens Geyer edited comment on THRIFT-3650 at 2/19/16 8:34 PM: ------------------------------------------------------------- Thanks to Fynn who [first reported the problem on SO|http://stackoverflow.com/q/35488379/499466]. was (Author: jensg): Thanks to Fynn who [first reported the problem on SO](http://stackoverflow.com/q/35488379/499466). > incorrect union serialization > ------------------------------ > > Key: THRIFT-3650 > URL: https://issues.apache.org/jira/browse/THRIFT-3650 > Project: Thrift > Issue Type: Bug > Components: C++ - Compiler > Reporter: Jens Geyer > > With C++ the following {{union}} generates incorrect serialization code: > {code} > union type_ex > { > 1 : string STRING, > 2 : i64 INT64, > 3 : double DOUBLE > } > {code} > This results in all three fields being *unconditionally* written, which not > only wastes space on the wire, but also sets all {{__isset}} bits during > deserialization. This makes it a bit hard to the other side to find out which > {{union}} field is the right one. > {code} > uint32_t type_ex::write(::apache::thrift::protocol::TProtocol* oprot) const { > uint32_t xfer = 0; > apache::thrift::protocol::TOutputRecursionTracker tracker(*oprot); > xfer += oprot->writeStructBegin("type_ex"); > xfer += oprot->writeFieldBegin("STRING", > ::apache::thrift::protocol::T_STRING, 1); > xfer += oprot->writeString(this->STRING); > xfer += oprot->writeFieldEnd(); > xfer += oprot->writeFieldBegin("INT64", ::apache::thrift::protocol::T_I64, > 2); > xfer += oprot->writeI64(this->INT64); > xfer += oprot->writeFieldEnd(); > xfer += oprot->writeFieldBegin("DOUBLE", > ::apache::thrift::protocol::T_DOUBLE, 3); > xfer += oprot->writeDouble(this->DOUBLE); > xfer += oprot->writeFieldEnd(); > xfer += oprot->writeFieldStop(); > xfer += oprot->writeStructEnd(); > return xfer; > } > {code} > *Workaround* > Add explicit {{optionals}}: > {code} > union type_ex > { > 1 : optional string STRING, > 2 : optional i64 INT64, > 3 : optional double DOUBLE > } > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)