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This page tracks breaking changes between Miles releases and how to update your code or launch scripts.

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Train loop: sync → async

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What changed

train.py, train_async.py, and RayTrainGroup now use Python async/await instead of ray.get()-style sync calls.

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Why

Async code is more expressive when you need to overlap work. A concrete example: in fault tolerance we want to capture Ray actor errors and retry actor_model.train while still letting critic_model.train proceed. That’s hard to write with synchronous ray.get.

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How to migrate mechanically

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1. Make train async

- def train(args):
+ async def train(args):
      ...

  if __name__ == "__main__":
-     train(parse_args())
+     asyncio.run(train(parse_args()))

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2. Drop async_ prefixes; ray.get(x) → await x

- ray.get(group.async_init(...))
+ await group.init(...)

- ray.get(group.async_train(...))
+ await group.train(...)

- group.save_model(...)
+ await group.save_model(...)

- group.update_weights()
+ await group.update_weights()

- ray.get(rollout_manager.generate.remote(rollout_id))
+ await rollout_manager.generate.remote(rollout_id)
Same pattern applies to offload, onload, clear_memory, connect, set_rollout_manager.

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3. Dispatch handles → eager tasks

- handle = critic.async_train(...)
- ray.get(actor.async_train(...))
- ray.get(handle)

+ task = await eager_create_task(critic.train(...))
+ await actor.train(...)
+ await task

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4. create_training_models is now async

- actor, critic = create_training_models(args, pgs, rollout_manager)
+ actor, critic = await create_training_models(args, pgs, rollout_manager)

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Other recent breakages

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v0.0.8 → v0.0.9

  • --rollout-router-ip renamed to --sglang-router-ip.
  • --rm-path renamed to --custom-rm-path (legacy alias warns then exits in v0.1.0).
  • --num-rollout is now required (previously defaulted to 1000).

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v0.0.7 → v0.0.8

  • Default --save-interval changed from 10 → 100. Set explicitly if you relied on the old cadence.
  • --apply-chat-template is no longer implicit when prompt is a list; pass it explicitly.

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Versioning policy

  • Patch (0.1.x): bug fixes only, no flag changes.
  • Minor (0.x.0): new features; old flags marked deprecated, alias kept for one minor.
  • Major (x.0.0): breaking changes; deprecated aliases removed.
We log a clear deprecation warning at startup whenever you use a soon-to-be-removed flag — pay attention to those, they’re the cheapest way to migrate ahead of time.

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Compatibility matrix

MilesSGLangMegatron-LMNotes
0.1.00.4.4+mcore-r0.10Current stable
0.0.90.4.3mcore-r0.9
0.0.80.4.2mcore-r0.8Last sync-loop release
If you’re pinned to a specific SGLang or Megatron version, use the matching Miles release rather than mixing.