Decoding of map<int64, Message> results in error if a Message has only default values

[Leulz]

protobuf.js version: 6.11.3

I have filed an issue on grpc/grpc-node#2254, and they have told me that I should file an issue here. I will copy and paste some parts describing the problem:

I have a proto3 file that defines a service with a method that returns a message like the Outer here:

message Outer {
    map<int64, Inner> inners = 1;
}

message Inner {
    int64 field = 1;
}

If Outer has only one key-value pair, whose Inner has the field with its default value (in this case, 0), I am getting an error like the following: Response message parsing error: Cannot read properties of null (reading 'field'). This happens even when I pass defaults: true. By the way, I am doing this using NestJS, which uses @grpc/proto-loader by default.

I have tried changing the loader configurations, but to no avail. The error persists.

I have confirmed that the error is with not passing any field different from the type's default by adding a second field to the Inner message and sending an Outer like Outer { inners: {1: Inner {field: 0, other_field: 1}}}. Everything worked then.

Stack trace:

TypeError: Cannot read properties of null (reading 'field')
    at Type.Inner$toObject [as toObject] (eval at Codegen (.../node_modules/@protobufjs/codegen/index.js:50:33), <anonymous>:19:8)
    at Type.toObject (.../node_modules/@grpc/proto-loader/node_modules/protobufjs/src/type.js:567:25)
    at Type.MessageThatContainsTheMap$toObject [as toObject] (eval at Codegen (.../node_modules/@protobufjs/codegen/index.js:50:33), <anonymous>:29:34)
    at Type.OuterMessageThatContainsMessageThatContainsTheMap$toObject [as toObject] (eval at Codegen (.../node_modules/@protobufjs/codegen/index.js:50:33), <anonymous>:13:32)
    at Type.toObject (.../node_modules/@grpc/proto-loader/node_modules/protobufjs/src/type.js:567:25)
    at Object.deserialize [as responseDeserialize] (.../node_modules/@grpc/proto-loader/src/index.ts:209:16)
    at Object.onReceiveMessage (.../node_modules/@grpc/grpc-js/src/client-interceptors.ts:408:48)
    at .../node_modules/@grpc/grpc-js/src/call-stream.ts:402:22
    at processTicksAndRejections (node:internal/process/task_queues:78:11)

[Leulz]

It seems like it's actually because protobuf.js does not handle an optimization that exists in Rust's prost's implementation, as described in this issue: tokio-rs/prost#99

[acode-x]

Hi @Leulz ,
I think protobuf.js v7.0.0 fixes above #1348

[Leulz]

Hi @Leulz ,
I think protobuf.js v7.0.0 fixes above #1348

Seems like it, thank you for pointing it out!