add the method 'unregister_reporters' for the class Report, update un…

…it tests

src/syngen/VERSION

@@ -1 +1 @@
-0.9.48
+0.9.49rc0

src/syngen/ml/handlers/handlers.py

@@ -19,6 +19,7 @@
 
 from syngen.ml.vae import *  # noqa: F403
 from syngen.ml.data_loaders import DataLoader, DataFrameFetcher
+from syngen.ml.reporters import Report
 from syngen.ml.vae.models.dataset import Dataset
 from syngen.ml.utils import (
     fetch_config,
@@ -492,6 +493,15 @@ def handle(self, **kwargs):
             else pd.DataFrame()
         )
         prepared_data = self._restore_empty_columns(prepared_data)
+        # workaround for the case when all columns are dropped
+        # with technical column
+        if self.dataset.tech_columns:
+            tech_columns = list(self.dataset.tech_columns)
+            prepared_data = prepared_data.drop(tech_columns, axis=1)
+            Report().unregister_reporters(tech_columns)
+            logger.debug(f"Technical columns "
+                         f"{self.dataset.tech_columns} are dropped"
+                         f" from the generated table")
 
         is_pk = self._is_pk()
 

src/syngen/ml/reporters/reporters.py

@@ -1,5 +1,12 @@
 from abc import abstractmethod
-from typing import Dict, Tuple, Optional, Callable
+from typing import (
+    Dict,
+    Tuple,
+    Optional,
+    Callable,
+    Union,
+    List
+)
 import itertools
 from collections import defaultdict
 
@@ -188,7 +195,7 @@ class Report:
     Singleton metaclass for registration all needed reporters
     """
 
-    _reporters: Dict[str, Reporter] = {}
+    _reporters: Dict[str, Union[Reporter, List]] = {}
 
     def __new__(cls):
         if not hasattr(cls, "instance"):
@@ -204,6 +211,14 @@ def register_reporter(cls, table: str, reporter: Reporter):
         list_of_reporters.append(reporter)
         cls._reporters[table] = list_of_reporters
 
+    @classmethod
+    def unregister_reporters(cls, tables: List[str]):
+        """
+        Unregister all reporters for tables
+        """
+        for table in tables:
+            cls._reporters[table] = list()
+
     @classmethod
     def clear_report(cls):
         """

src/syngen/ml/vae/models/dataset.py

@@ -60,6 +60,7 @@ def __init__(
         self.uuid_columns: Set = set()
         self.uuid_columns_types: Dict = dict()
         self.dropped_columns: Set = set()
+        self.tech_columns: Set = set()
         self.order_of_columns: List = list()
         self.custom_categorical_columns: Set = set()
         self.categorical_columns: Set = set()
@@ -1320,6 +1321,20 @@ def pipeline(self) -> pd.DataFrame:
             elif column in self.uuid_columns:
                 logger.info(f"Column '{column}' defined as UUID column")
                 self._assign_uuid_null_feature(column)
+
+        # workaround for the case when all columns are dropped
+        # add a technical column to proceed with the training process
+        if not self.features:
+            tech_column = "syngen_tech_column"
+            logger.warning(
+                f"There are no columns left to train on for '{self.table_name}'. "
+                f"Adding a technical column '{tech_column}' to proceed "
+                f"with the training process."
+            )
+            self.df[tech_column] = 1
+            self._assign_float_feature(tech_column)
+            self.tech_columns.add(tech_column)
+
         self.fit()
 
         # The end of the run related to the preprocessing stage

src/tests/unit/dataset/test_dataset.py

@@ -150,6 +150,7 @@ def test_save_dataset(rp_logger):
         "float_columns",
         "int_columns",
         "date_columns",
+        "tech_columns",
         "date_mapping",
         "binary_columns",
         "email_columns",