Backtest/joblib worker crash: AttributeError: No such registered in self._config

[maxilirator]

🐛 Bug Description

During backtests that spawn joblib workers, fresh worker processes import Qlib and call config.register_from_C(g_config). That function checks C.registered before copying g_config. Because worker C._config lacks the key on first access, Config.getattr raises:
AttributeError: No such registered in self._config

Proposed fix
In qlib/config.py register_from_C:
Replace:
if C.registered and skip_register:
With:
if getattr(C, "registered", False) and skip_register:
After merging g_config into the worker:
self._config["registered"] = True

To Reproduce

qlib.backtest.report.PortfolioMetrics._cal_benchmark → qlib.utils.resam.get_higher_eq_freq_feature → D.features → DatasetD.dataset → dataset_processor → joblib.Parallel → qlib.data.data.inst_calculator → qlib.config.C.register_from_C
qlib/config.py: register_from_C:
if C.registered and skip_register: # raises AttributeError (key missing in worker)

Expected Behavior

Worker config should safely sync from the main process without assuming the key exists.

Environment

OS: Windows 11
Python: 3.10
Qlib: 0.9.7
Joblib: version bundled with Qlib deps
Backend: default process-based Parallel

Additional Notes

This avoids needing user-side hacks or thread-only backends. Defaulting the flag to False on first access is consistent with intent and prevents the worker crash.

[SunsetWolf]

Hi, @maxilirator
Thanks for reporting this issue and providing such a clear analysis and proposed fix — that’s really helpful! 🙏
Could you please share the exact steps or a minimal example to reproduce this error?
It would be great to know what specific backtest setup or script triggered the crash on your side, so we can verify and test the fix more effectively.