Using compare plugin does not work for oneof

[johanbrandhorst]

Hi,

When using a message which contains a message with a oneof variable and using the setting to generate compare methods, the generated interface for the variable does not have the Compare() function generated as part of the interface.

Here is a gist which reproduces the error:

https://gist.github.com/johanbrandhorst/783e0908940a2f81d7aef7b1ac93472e

The offending line is my.pb.go:44:

type isValue_Type interface {
    isValue_Type()
}

Should be

type isValue_Type interface {
    isValue_Type()
    Compare(interface{}) int
}

[johanbrandhorst]

It also generates invalid tests, but I will raise that as a separate issue

[awalterschulze]

I think this is the same issue

[awalterschulze]

The compare plugin was probably not tested with a oneof message

[johanbrandhorst]

Ok, I'll skip that issue

[johanbrandhorst]

This might also apply to the ProtoSize plugin, should I make a separate issue for that?

[awalterschulze]

Do you get a compile error, then yes.

[awalterschulze]

Here is a design for a fix:

We have to generated a type switch for each possible one of type for this and that.
This will then assign the oneof field number for each type to a thisType+NumGen.Next() and thatType+NumGen.Next() variable.
Then we compare the numbers, if they are equal, the Compare method for that field is called.
If they differ we return 1 or -1 as appropriate.

Anybody up for implementing this?