IndexError: list index out of range

[klokedm]

Environment:

• MLJar Studio 0.3.1
• Windows 11
• Built-in Python Evnironment

When using the mljar studio I get the error message: "IndexError: list index out of range" with the stack trace:

Error for 1_Default_LightGBM

list index out of range
Traceback (most recent call last):
File "\?\C:\Users\marko\AppData\Roaming\mljar-studio\jlab_server\Lib\site-packages\supervised\base_automl.py", line 1178, in _fit
trained = self.train_model(params)
^^^^^^^^^^^^^^^^^^^^^^^^
File "\?\C:\Users\marko\AppData\Roaming\mljar-studio\jlab_server\Lib\site-packages\supervised\base_automl.py", line 384, in train_model
mf.train(results_path, model_subpath)
File "\?\C:\Users\marko\AppData\Roaming\mljar-studio\jlab_server\Lib\site-packages\supervised\model_framework.py", line 192, in train
].fit_and_transform(
^^^^^^^^^^^^^^^^^^
File "\?\C:\Users\marko\AppData\Roaming\mljar-studio\jlab_server\Lib\site-packages\supervised\preprocessing\preprocessing.py", line 175, in fit_and_transform
missing.fit(X_train)
File "\?\C:\Users\marko\AppData\Roaming\mljar-studio\jlab_server\Lib\site-packages\supervised\preprocessing\preprocessing_missing.py", line 26, in fit
X = self._fit_na_fill(X)
^^^^^^^^^^^^^^^^^^^^
File "\?\C:\Users\marko\AppData\Roaming\mljar-studio\jlab_server\Lib\site-packages\supervised\preprocessing\preprocessing_missing.py", line 32, in _fit_na_fill
self._na_fill_params[column] = self._get_fill_value(X[column])
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "\?\C:\Users\marko\AppData\Roaming\mljar-studio\jlab_server\Lib\site-packages\supervised\preprocessing\preprocessing_missing.py", line 43, in _get_fill_value
return PreprocessingUtils.get_most_frequent(x)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "\?\C:\Users\marko\AppData\Roaming\mljar-studio\jlab_server\Lib\site-packages\supervised\preprocessing\preprocessing_utils.py", line 114, in get_most_frequent
first = sorted(dict(a).items(), key=lambda x: -x[1])[0]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^

[vivek41-glitch]

Hi! I'd like to work on this bug.

The root cause is in preprocessing_utils.py — get_most_frequent() crashes when the sorted list is empty. I'll add a guard check to handle this case gracefully.