Fix evaluation workers hanging due to missing exec_run() timeouts

[sarvanithin]

User description

Problem

Evaluation workers hang indefinitely when running example 3 (03_parallel_eval_with_api.py). Symptom: 18 agent steps observed but wall-clock time far exceeding the expected 18 × 2 min = 36 min. Reported by Josh.

Root Cause

Four exec_run() call sites were missing timeout_s, so a single unresponsive container exec could block the entire evaluation indefinitely — even though per-operation timeouts appear to exist elsewhere.

1. mini_swe_agent.py — agent setup has no timeout

The 4 uname commands run with no timeout_s. If Daytona is slow during container startup, the code_agent_task hangs before making any LLM request, blocking _get_time_step() forever via asyncio.wait().

2. code_env.py (_compute_reward) — test execution has no timeout

bash {test_path} and reward file cat calls use no timeout. If a test script contains an infinite loop or the container hangs during scoring, the episode hangs indefinitely after the agent finishes all its steps.

3. code_env.py (_get_time_step) — asyncio.wait() has no timeout

No backstop at the step level. Even when per-operation timeouts are set, if the underlying Daytona SDK delays propagating CancelledError (e.g. during server-side cancel cleanup), the effective timeout can far exceed the configured value.

4. examples/03_parallel_eval_with_api.py — no per-task wall-clock limit

A hung task holds a semaphore slot indefinitely, reducing effective parallelism from num_parallel_workers down as workers pile up.

Fix

File	Change
mini_swe_agent.py	Add timeout_s=30 to the 4 setup exec_run() calls
code_env.py	Add _REWARD_EXEC_TIMEOUT_S = 300 (5 min) to all exec calls in _compute_reward() and _parse_reward_file()
code_env.py	Add timeout=_GET_TIME_STEP_TIMEOUT_S (10 min) to asyncio.wait() in _get_time_step() with a clear TimeoutError
examples/03_parallel_eval_with_api.py	Wrap each evaluate_task() with asyncio.wait_for(timeout=args.task_timeout_s) (default 30 min); timed-out tasks surface as errors via gather(return_exceptions=True)

Testing

All 163 existing tests pass. End-to-end testing with Daytona in progress.

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Generated description

Below is a concise technical summary of the changes proposed in this PR:
Implements comprehensive timeouts across container execution calls and task management to prevent evaluation workers from hanging indefinitely. These changes ensure that unresponsive container operations or delayed cancellations do not block system resources or parallel execution slots.

Topic	Details
Execution Timeouts	Integrates timeout_s into exec_run calls within MiniSWECodeAgent and CodeEnvironment to prevent blocking during agent setup, test execution, and reward parsing. Modified files (2) src/ares/code_agents/mini_swe_agent.py src/ares/environments/code_env.py Latest Contributors(2) User Commit Date joshua.greaves@gmail.com Add-an-LLMResponse-mod... January 29, 2026 ryan@withmartian.com Allowed-all-harbor-dat... January 28, 2026
Task Safeguards	Adds a 10-minute backstop to _get_time_step using asyncio.wait and introduces a configurable task_timeout_s in the parallel evaluation script to safeguard against hung tasks. Modified files (2) examples/03_parallel_eval_with_api.py src/ares/environments/code_env.py Latest Contributors(2) User Commit Date ryan@withmartian.com Fail-fast-cleanups-76 January 29, 2026 joshua.greaves@gmail.com Fail-fast-if-required-... January 29, 2026

This pull request is reviewed by Baz. Review like a pro on (Baz).