Handling deserializing new Values on enums with UNKNOWN_ENUM_VALUE_(enumName)_(newValue)

[nbergaoui]

Hi all ,
We are using the proto version 3.0.0 and your plugin to generate deserialization classes from our protobuf files .
Here is the version used :
org.xolstice.maven.plugins
protobuf-maven-plugin
0.5.0

com.google.protobuf:protoc:3.0.0:exe:${os.detected.classifier}

Now when we look at our proto file it looks like that :

enum TypeCreneauProto {
UNKNOWN_TYPE_CRENEAU_PROTO = 0;
JOURNEE = 1;
MATINEE = 2;
APRES_MIDI = 3;
DEBUT_MATINEE = 4;
FIN_MATINEE = 5;
DEBUT_APRES_MIDI = 6;
FIN_APRES_MIDI = 7;
AU_PLUS_TOT = 8;
}

When we receive a value 9 , well it is supposed to put the value to the default one ie : UNKNOWN_TYPE_CRENEAU_PROTO , but it still creates a new value non exiting on our enum

UNKNOWN_ENUM_VALUE_TypeCreneauProto_9

this causes us trouble when serialising back to other formats .
Why does it bevave this way ? It looks like a bug as what is annouced it that it get to the default value ( set to 0 on the top of the enum )
The field is optionnal ( no mention for the "optional" tag as we are using proto 3.0.0

Can you please get back to me on this issue ?
Thanks