[trainer] fix: resolve dataset config in agent loop

[yyDing1]

What does this PR do?

line 516: dataset_config=self.config.data

verl/verl/experimental/agent_loop/agent_loop.py

Lines 509 to 517 in 772c224

	agent_loop = hydra.utils.instantiate(
	config=agent_loop_config,
	trainer_config=DictConfigWrap(config=self.config),
	server_manager=self.server_manager,
	tokenizer=self.tokenizer,
	processor=self.processor,
	dataset_cls=self.dataset_cls,
	dataset_config=self.config.data,
	)

self.config.data may have unresolved arguments like 'tool_config_path': '${oc.select:actor_rollout_ref.rollout.multi_turn.tool_config_path, null}', which cannot be instantiated. This will cause error

*** omegaconf.errors.InterpolationResolutionError: TypeError raised while resolving interpolation: Index 'actor_rollout_ref' (str) is not an int

Solution:

Wrap it in DictConfigWrap, so that it will not be initialized in hydra resolve config.

Checklist Before Starting

• Search for similar PRs. Paste at least one query link here: ...
• Format the PR title as [{modules}] {type}: {description} (This will be checked by the CI)
  • {modules} include fsdp, megatron, veomni, sglang, vllm, rollout, trainer, ci, training_utils, recipe, hardware, deployment, ray, worker, single_controller, misc, perf, model, algo, env, tool, ckpt, doc, data, cfg, reward
  • If this PR involves multiple modules, separate them with , like [megatron, fsdp, doc]
  • {type} is in feat, fix, refactor, chore, test
  • If this PR breaks any API (CLI arguments, config, function signature, etc.), add [BREAKING] to the beginning of the title.
  • Example: [BREAKING][fsdp, megatron] feat: dynamic batching

Test

For changes that can not be tested by CI (e.g., algorithm implementation, new model support), validate by experiment(s) and show results like training curve plots, evaluation results, etc.

API and Usage Example

Demonstrate how the API changes if any, and provide usage example(s) if possible.

# Add code snippet or script demonstrating how to use this

Design & Code Changes

Demonstrate the high-level design if this PR is complex, and list the specific changes.

Checklist Before Submitting

Important

Please check all the following items before requesting a review, otherwise the reviewer might deprioritize this PR for review.

• Read the Contribute Guide.
• Apply pre-commit checks: pre-commit install && pre-commit run --all-files --show-diff-on-failure --color=always
• Add / Update the documentation.
• Add unit or end-to-end test(s) to the CI workflow to cover all the code. If not feasible, explain why: ...
• Once your PR is ready for CI, send a message in the ci-request channel in the verl Slack workspace. (If not accessible, please try the Feishu group (飞书群).)
• If your PR is related to the recipe submodule, please also update the reference to the submodule commit via git submodule update --remote or cd recipe && git pull origin main.

[gemini-code-assist]

Code Review

This pull request correctly resolves an OmegaConf interpolation error by wrapping the dataset_config in a DictConfigWrap class to prevent premature resolution by Hydra. The changes are consistent and effectively address the issue. I've also identified a critical race condition in the AsyncLLMServerManager that is closely related to the code being changed and should be addressed.