Improvement in config_regressors Null Check in df_utils.py to Prevent AttributeError

[Chrystiano]

Prerequisites

• I have done all of the following:
  • Reproduced the problem in a new virtualenv with only neuralprophet installed, directly from GitHub.
  • Checked the Answered Questions on the Github Discussion board and found no solution to my issue.
  • Verified that my issue isn't already filed under existing issues.
  • Considered posting a question but determined my issue is a bug that needs addressing.

Describe the bug

An AttributeError occurs when config_regressors is None, specifically in df_utils.py at line 991, when attempting to access regressors attribute of a NoneType object in configurations using future regressors.

To Reproduce

1. Install NeuralProphet from GitHub in a new virtual environment.
2. With a DataFrame that includes a future regressor column 'temperature'. (https://neuralprophet.com/tutorials/tutorial06.html#Tutorial-6:-Future-regressors)
3. Setting the model to include a future regressor with add_future_regressor('temperature').
4. After running m.fit(df) followed by m.predict(df).
5. Encountered AttributeError: 'NoneType' object has no attribute 'regressors'.

Expected behavior

Expected the model to handle future regressors gracefully without throwing an error, even when config_regressors is not explicitly defined for some paths through the data.

What actually happens

The error occurs consistently when predicting with future regressors without prior validation of config_regressors.

Environment

• Python environment: Python 3.11.5, in a standalone venv with only neuralprophet installed.
• NeuralProphet version: 1.0.0rc7.

Additional context

The issue can be mitigated by checking if config_regressors is not None before attempting to access its regressors attribute, ensuring robust error handling and preventing runtime errors.

[ourownstory]

Thank you @Chrystiano for providing a clear issue description. I will look into this.

[ourownstory]

This bug was introduced in #1008

[ourownstory]

@Chrystiano fixed in #1536. Will be merged shortly and will create new RC with fix.