Bug: get_factor_env() overwrites extra_volumes with empty dict, causing StopIteration in QTDockerEnv.prepare()

[newhwa]

Description

Running rdagent fin_factor with Docker backend crashes immediately with StopIteration because get_factor_env() unconditionally overwrites the QlibDockerConf default extra_volumes with an empty dict.

Environment

• rdagent version: 0.8.1.dev28
• Python: 3.12
• OS: Ubuntu 24.04 (WSL2)
• Backend: Docker (MODEL_CoSTEER_env_type=docker)

Steps to Reproduce

1. Install rdagent with default configuration
2. Set MODEL_CoSTEER_env_type=docker in .env
3. Ensure qlib data exists at ~/.qlib/qlib_data/cn_data
4. Run:

   rdagent fin_factor --loop-n 3

Expected Behavior

QTDockerEnv should use its default extra_volumes from QlibDockerConf (mounting ~/.qlib/ to /root/.qlib/), and prepare() should succeed.

Actual Behavior

StopIteration

Full traceback:

rdagent/app/qlib_rd_loop/factor.py:54 in main
    factor_loop = FactorRDLoop(FACTOR_PROP_SETTING)
rdagent/components/workflow/rd_loop.py:34 in __init__
    scen: Scenario = import_class(PROP_SETTING.scen)()
rdagent/scenarios/qlib/experiment/factor_experiment.py:35 in __init__
    runtime_environment=self.get_runtime_environment(),
rdagent/scenarios/qlib/experiment/factor_experiment.py:102 in get_runtime_environment
    factor_env = get_factor_env()
rdagent/components/coder/factor_coder/config.py:53 in get_factor_env
    env.prepare()
rdagent/utils/env.py:1522 in prepare
    qlib_data_path = next(iter(self.conf.extra_volumes.keys()))

Root Cause

In rdagent/components/coder/factor_coder/config.py, get_factor_env():

def get_factor_env(
    conf_type: Optional[str] = None,
    extra_volumes: dict = {},   # default is empty dict
    ...
) -> Env:
    ...
    env = QTDockerEnv()  # QlibDockerConf sets extra_volumes = {"~/.qlib/": {"bind": "/root/.qlib/", "mode": "rw"}}
    env.conf.extra_volumes = extra_volumes.copy()  # BUG: unconditionally overwrites with {}
    ...
    env.prepare()  # next(iter(empty_dict.keys())) raises StopIteration

QTDockerEnv.__init__ uses QlibDockerConf() which correctly defines:

extra_volumes: dict = {
    str(Path("~/.qlib/").expanduser().resolve().absolute()): {
        "bind": "/root/.qlib/",
        "mode": "rw",
    }
}

But this default is immediately wiped out by get_factor_env().

Suggested Fix

Only override extra_volumes when the caller explicitly passes a non-empty value:

# Before (broken)
env.conf.extra_volumes = extra_volumes.copy()

# After (fixed)
if extra_volumes:
    env.conf.extra_volumes = extra_volumes.copy()

Alternatively, use None as the default sentinel (more idiomatic):

def get_factor_env(
    conf_type: Optional[str] = None,
    extra_volumes: Optional[dict] = None,
    ...
) -> Env:
    ...
    if extra_volumes is not None:
        env.conf.extra_volumes = extra_volumes.copy()

The same pattern likely exists in rdagent/components/coder/model_coder/config.py — get_model_env() may have the same bug.

Affected Files

• rdagent/components/coder/factor_coder/config.py (line 51)
• rdagent/components/coder/model_coder/config.py (likely same issue)
• rdagent/utils/env.py (line 1522 — prepare() doesn't guard against empty extra_volumes)