How to determine the cycles in protobuff?

Question

let's say I have the following mode.proto file:

message EntityD {
    optional EntityE ePointer = 1;
    optional int32 dField = 2;
}

message EntityE {
    optional EntityD dPointer = 1;
    optional int32 eField = 2;
}

it has 2 entities - D and E, which allow stitching. my problem is that after generating java code from the above * .proto im could not create a loop:

public static void main(String[] args) throws Exception {
    Model.EntityD.Builder dBuilder = Model.EntityD.newBuilder();
    Model.EntityE.Builder eBuilder = Model.EntityE.newBuilder();

    dBuilder.setDField(42);
    eBuilder.setEField(7);
    dBuilder.setEPointer(eBuilder);
    eBuilder.setDPointer(dBuilder);

    Model.EntityD d = dBuilder.build();
    Model.EntityE e = eBuilder.build();

    System.err.println("same d: "+(d==e.getDPointer()));
    System.err.println("same e: "+(e==d.getEPointer()));
}

im trying to create a simple cycle D ↔ E. Instead, I get the following:

same d: false 
same e: false

In the created model there is a cycle, but only starting from a certain depth.

is a problem with probuf generated java code? Does protobuf really support loops on the chart? What is the expected result for this in other "output" protobuff languages? (namely C ++)

Answer 1

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