extending field and message options

[Arpit Baldeva]

Hi,

I have my proto file like following.

package example;

message ExFieldOptions 

{

  map<string, string> meta_data = 1;

}

extend google.protobuf.FieldOptions 

{

    ExFieldOptions exOptions = 4245; 

}

extend google.protobuf.MessageOptions 

{

    ExFieldOptions exOptions = 4245; 

} 

When I run it through ProtoC (for C++ code generation), I run into an error

"exOptions" is already defined in "example".

Is this a bug? Or is it required that extension name need to be unique across options?

Thanks. 

[Adam Cozzette]

I believe this is to be expected, because these top-level extensions would end up having the same name. For example in C++ they would both be called example::exOptions and so there would be a conflict there. To get around this you can either give them different names or keep the same names but nest them inside of messages, like this:

message MessageOptionsExtension {

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[Josh Humphries]

All fully-qualified symbols must be a unique for an invocation of protoc. In the generated code, you can refer to the generated extension (just like referring to generated messages, enums, and services), and if their fully-qualified names weren't unique, it would result in compilation errors in the generated code.

----
Josh Humphries
jh...@bluegosling.com

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