protobuf.dart#952 reproducer #1

a.proto

syntax = "proto3";
message A {}

b.proto

syntax = "proto3";
message B {}

Dockerfile

FROM dart:3.7.0-sdk

RUN apt-get update
RUN apt-get install -y protobuf-compiler libprotobuf-dev

RUN dart pub global activate protoc_plugin

has_a.proto

syntax = "proto3";

import "a.proto";

message HasA {
  A a = 1;
}

has_ab.proto

syntax = "proto3";

import "a.proto";
import "b.proto";

message HasAB {
  A a = 1;
  B b = 2;
}

has_b.proto

syntax = "proto3";

import "b.proto";

message HasB {
  B b = 1;
}

repro.sh

#!/bin/sh
set -eu

dart --version
dart pub global list
protoc --version
printf '\n'

rm -rf out_ab out_ba
mkdir out_ab out_ba

protoc -I/src --dart_out=out_ab /src/has_a.proto /src/has_b.proto /src/has_ab.proto
protoc -I/src --dart_out=out_ba /src/has_b.proto /src/has_a.proto /src/has_ab.proto

diff -u out_ab/has_ab.pb.dart out_ba/has_ab.pb.dart

run.sh

#!/bin/sh
set -eu
image=dart-protobuf-952
docker build -t "${image}" .
docker run --rm -v "$PWD:/src:ro" "${image}" /src/repro.sh