fix: analysis report when there is a column with mixed data types

src/data_designer/engine/analysis/column_profilers/base.py

@@ -7,7 +7,6 @@
 from abc import ABC, abstractmethod
 
 import pandas as pd
-import pyarrow as pa
 from pydantic import BaseModel, model_validator
 from typing_extensions import Self
 
@@ -29,12 +28,6 @@ def validate_column_exists(self) -> Self:
             raise ValueError(f"Column {self.column_config.name!r} not found in DataFrame")
         return self
 
-    @model_validator(mode="after")
-    def ensure_pyarrow_backend(self) -> Self:
-        if not all(isinstance(dtype, pd.ArrowDtype) for dtype in self.df.dtypes):
-            self.df = pa.Table.from_pandas(self.df).to_pandas(types_mapper=pd.ArrowDtype)
-        return self
-
     def as_tuple(self) -> tuple[SingleColumnConfig, pd.DataFrame]:
         return (self.column_config, self.df)
 

src/data_designer/engine/analysis/column_statistics.py

@@ -59,7 +59,7 @@ def calculate(self) -> Self:
         )
 
     def calculate_general_column_info(self) -> dict[str, Any]:
-        return calculate_general_column_info(self.column_config, self.df)
+        return calculate_general_column_info(self.column_config.name, self.df)
 
     def __repr__(self) -> str:
         params = []
@@ -93,7 +93,7 @@ def calculate_sampler_distribution(self) -> dict[str, Any]:
         return (
             {
                 "sampler_type": SamplerType(self.column_config.sampler_type),
-                **calculate_column_distribution(self.column_config, self.df, dist_type),
+                **calculate_column_distribution(self.column_config.name, self.df, dist_type),
             }
             if make_dist
             else {
@@ -109,7 +109,7 @@ class SeedDatasetColumnStatisticsCalculator(GeneralColumnStatisticsCalculator):
 
 class ValidationColumnStatisticsCalculator(GeneralColumnStatisticsCalculator):
     def calculate_validation_column_info(self) -> dict[str, Any]:
-        return calculate_validation_column_info(self.column_config, self.df)
+        return calculate_validation_column_info(self.column_config.name, self.df)
 
 
 class ExpressionColumnStatisticsCalculator(GeneralColumnStatisticsCalculator): ...

src/data_designer/engine/analysis/dataset_profiler.py

@@ -6,6 +6,7 @@
 from functools import cached_property
 
 import pandas as pd
+import pyarrow as pa
 from pydantic import Field, field_validator
 
 from data_designer.config.analysis.column_profilers import ColumnProfilerConfigT
@@ -19,10 +20,8 @@
 from data_designer.engine.analysis.column_profilers.base import ColumnConfigWithDataFrame, ColumnProfiler
 from data_designer.engine.analysis.column_statistics import get_column_statistics_calculator
 from data_designer.engine.analysis.errors import DatasetProfilerConfigurationError
-from data_designer.engine.dataset_builders.multi_column_configs import (
-    DatasetBuilderColumnConfigT,
-    MultiColumnConfig,
-)
+from data_designer.engine.analysis.utils.column_statistics_calculations import has_pyarrow_backend
+from data_designer.engine.dataset_builders.multi_column_configs import DatasetBuilderColumnConfigT, MultiColumnConfig
 from data_designer.engine.registry.data_designer_registry import DataDesignerRegistry
 from data_designer.engine.resources.resource_provider import ResourceProvider
 
@@ -68,6 +67,7 @@ def profile_dataset(
         logger.info("📐 Measuring dataset column statistics:")
 
         self._validate_schema_consistency(list(dataset.columns))
+        dataset = self._convert_to_pyarrow_backend_if_needed(dataset)
 
         column_statistics = []
         for c in self.config.column_configs:
@@ -100,6 +100,18 @@ def profile_dataset(
             column_profiles=column_profiles if column_profiles else None,
         )
 
+    def _convert_to_pyarrow_backend_if_needed(self, dataset: pd.DataFrame) -> pd.DataFrame:
+        if not has_pyarrow_backend(dataset):
+            try:
+                dataset = pa.Table.from_pandas(dataset).to_pandas(types_mapper=pd.ArrowDtype)
+            except Exception:
+                logger.warning(
+                    "⚠️ Unable to convert the dataset to a PyArrow backend. This is often due to at least "
+                    "one column having mixed data types. As a result, the reported data types "
+                    "will be inferred from the type of the first non-null value of each column."
+                )
+        return dataset
+
     def _create_column_profiler(self, profiler_config: ColumnProfilerConfigT) -> ColumnProfiler:
         return self.registry.column_profilers.get_for_config_type(type(profiler_config))(
             config=profiler_config, resource_provider=self.resource_provider

src/data_designer/engine/analysis/utils/column_statistics_calculations.py

@@ -18,11 +18,7 @@
     MissingValue,
     NumericalDistribution,
 )
-from data_designer.config.column_configs import (
-    LLMTextColumnConfig,
-    SingleColumnConfig,
-    ValidationColumnConfig,
-)
+from data_designer.config.column_configs import LLMTextColumnConfig
 from data_designer.engine.column_generators.generators.llm_generators import (
     PromptType,
     RecordBasedPromptRenderer,
@@ -39,41 +35,54 @@
 
 
 def calculate_column_distribution(
-    column_config: SingleColumnConfig, df: pd.DataFrame, distribution_type: ColumnDistributionType
+    column_name: str, df: pd.DataFrame, distribution_type: ColumnDistributionType
 ) -> dict[str, CategoricalDistribution | NumericalDistribution | MissingValue | None]:
     distribution_type = ColumnDistributionType(distribution_type)
     try:
         if distribution_type == ColumnDistributionType.CATEGORICAL:
             return {
                 "distribution_type": ColumnDistributionType.CATEGORICAL,
-                "distribution": CategoricalDistribution.from_series(df[column_config.name]),
+                "distribution": CategoricalDistribution.from_series(df[column_name]),
             }
 
         if distribution_type == ColumnDistributionType.NUMERICAL:
             return {
                 "distribution_type": ColumnDistributionType.NUMERICAL,
-                "distribution": NumericalDistribution.from_series(df[column_config.name]),
+                "distribution": NumericalDistribution.from_series(df[column_name]),
             }
     except Exception as e:
-        logger.warning(f"{WARNING_PREFIX} failed to calculate column distribution for '{column_config.name}' {e}")
+        logger.warning(f"{WARNING_PREFIX} failed to calculate column distribution for '{column_name}' {e}")
         return {
             "distribution_type": ColumnDistributionType.UNKNOWN,
             "distribution": MissingValue.CALCULATION_FAILED,
         }
 
 
-def calculate_general_column_info(column_config: SingleColumnConfig, df: pd.DataFrame) -> dict[str, Any]:
+def calculate_general_column_info(column_name: str, df: pd.DataFrame) -> dict[str, Any]:
     try:
-        _df = pd.DataFrame(df[column_config.name].apply(ensure_hashable))
+        _df = pd.DataFrame(df[column_name].apply(ensure_hashable))
+
+        if has_pyarrow_backend(df):
+            pyarrow_dtype = str(df[column_name].dtype.pyarrow_dtype)
+            simple_dtype = convert_pyarrow_dtype_to_simple_dtype(df[column_name].dtype.pyarrow_dtype)
+        else:
+            # We do not log a warning at the column-level because it would be too noisy.
+            # However, there is a logged warning at the dataset-profiler level.
+            try:
+                simple_dtype = get_column_data_type_from_first_non_null_value(column_name, df)
+            except Exception:
+                simple_dtype = MissingValue.CALCULATION_FAILED
+            pyarrow_dtype = "n/a"
+
         return {
-            "pyarrow_dtype": str(df[column_config.name].dtype.pyarrow_dtype),
-            "simple_dtype": convert_pyarrow_dtype_to_simple_dtype(df[column_config.name].dtype.pyarrow_dtype),
-            "num_records": len(_df[column_config.name]),
-            "num_null": _df[column_config.name].isnull().sum(),
-            "num_unique": _df[column_config.name].nunique(),
+            "pyarrow_dtype": pyarrow_dtype,
+            "simple_dtype": simple_dtype,
+            "num_records": len(_df[column_name]),
+            "num_null": _df[column_name].isnull().sum(),
+            "num_unique": _df[column_name].nunique(),
         }
     except Exception as e:
-        logger.warning(f"{WARNING_PREFIX} failed to calculate general column info for '{column_config.name}': {e}")
+        logger.warning(f"{WARNING_PREFIX} failed to calculate general column info for '{column_name}': {e}")
         return {
             "pyarrow_dtype": MissingValue.CALCULATION_FAILED,
             "simple_dtype": MissingValue.CALCULATION_FAILED,
@@ -115,11 +124,9 @@ def calculate_prompt_token_stats(
     }
 
 
-def calculate_completion_token_stats(
-    column_config: LLMTextColumnConfig, df: pd.DataFrame
-) -> dict[str, float | MissingValue]:
+def calculate_completion_token_stats(column_name: str, df: pd.DataFrame) -> dict[str, float | MissingValue]:
     try:
-        tokens_per_record = df[column_config.name].apply(
+        tokens_per_record = df[column_name].apply(
             lambda value: len(TOKENIZER.encode(str(value), disallowed_special=()))
         )
         return {
@@ -128,9 +135,7 @@ def calculate_completion_token_stats(
             "completion_tokens_stddev": tokens_per_record.std(),
         }
     except Exception as e:
-        logger.warning(
-            f"{WARNING_PREFIX} failed to calculate completion token stats for column {column_config.name}: {e}"
-        )
+        logger.warning(f"{WARNING_PREFIX} failed to calculate completion token stats for column {column_name}: {e}")
         return {
             "completion_tokens_mean": MissingValue.CALCULATION_FAILED,
             "completion_tokens_median": MissingValue.CALCULATION_FAILED,
@@ -141,16 +146,16 @@ def calculate_completion_token_stats(
 def calculate_token_stats(column_config: LLMTextColumnConfig, df: pd.DataFrame) -> dict[str, float | MissingValue]:
     return {
         **calculate_prompt_token_stats(column_config, df),
-        **calculate_completion_token_stats(column_config, df),
+        **calculate_completion_token_stats(column_config.name, df),
     }
 
 
-def calculate_validation_column_info(column_config: ValidationColumnConfig, df: pd.DataFrame) -> dict[str, Any]:
+def calculate_validation_column_info(column_name: str, df: pd.DataFrame) -> dict[str, Any]:
     try:
-        return {"num_valid_records": df[column_config.name].apply(lambda x: ensure_boolean(x["is_valid"])).sum()}
+        return {"num_valid_records": df[column_name].apply(lambda x: ensure_boolean(x["is_valid"])).sum()}
     except Exception as e:
         logger.warning(
-            f"{WARNING_PREFIX} failed to calculate code validation column info for column {column_config.name}: {e}"
+            f"{WARNING_PREFIX} failed to calculate code validation column info for column {column_name}: {e}"
         )
         return {"num_valid_records": MissingValue.CALCULATION_FAILED}
 
@@ -160,22 +165,33 @@ def convert_pyarrow_dtype_to_simple_dtype(pyarrow_dtype: pa.DataType) -> str:
         return f"list[{convert_pyarrow_dtype_to_simple_dtype(pyarrow_dtype.value_type)}]"
     if isinstance(pyarrow_dtype, pa.StructType):
         return "dict"
-    pyarrow_dtype_str = str(pyarrow_dtype)
-    if "int" in pyarrow_dtype_str:
+    return convert_to_simple_dtype(str(pyarrow_dtype))
+
+
+def convert_to_simple_dtype(dtype: str) -> str:
+    if "int" in dtype:
         return "int"
-    if "double" in pyarrow_dtype_str:
+    if "double" in dtype:
         return "float"
-    if "float" in pyarrow_dtype_str:
+    if "float" in dtype:
         return "float"
-    if "string" in pyarrow_dtype_str:
+    if "string" in dtype or dtype == "str":
         return "string"
-    if "timestamp" in pyarrow_dtype_str:
+    if "timestamp" in dtype:
         return "timestamp"
-    if "time" in pyarrow_dtype_str:
+    if "time" in dtype:
         return "time"
-    if "date" in pyarrow_dtype_str:
+    if "date" in dtype:
         return "date"
-    return pyarrow_dtype_str
+    return dtype
+
+
+def get_column_data_type_from_first_non_null_value(column_name: str, df: pd.DataFrame) -> str:
+    df_no_nulls = df[column_name].dropna()
+    if len(df_no_nulls) == 0:
+        return MissingValue.CALCULATION_FAILED
+    dtype = type(df_no_nulls.iloc[0]).__name__
+    return convert_to_simple_dtype(dtype)
 
 
 def ensure_hashable(x: Any) -> str:
@@ -207,3 +223,7 @@ def ensure_boolean(v: bool | str | int | None) -> bool:
     if v is None:
         return False
     raise ValueError(f"Invalid boolean value: {v}")
+
+
+def has_pyarrow_backend(df: pd.DataFrame) -> bool:
+    return all(isinstance(dtype, pd.ArrowDtype) for dtype in df.dtypes)

tests/engine/analysis/column_profilers/test_base.py

@@ -37,17 +37,6 @@ def test_column_config_with_dataframe_column_not_found_validation_error():
         ColumnConfigWithDataFrame(column_config=column_config, df=df)
 
 
-def test_column_config_with_dataframe_pyarrow_backend_conversion():
-    df = pd.DataFrame({"test_column": [1, 2, 3]})
-    column_config = SamplerColumnConfig(
-        name="test_column", sampler_type=SamplerType.CATEGORY, params={"values": [1, 2, 3]}
-    )
-
-    config_with_df = ColumnConfigWithDataFrame(column_config=column_config, df=df)
-
-    assert all(isinstance(dtype, pd.ArrowDtype) for dtype in config_with_df.df.dtypes)
-
-
 def test_column_config_with_dataframe_as_tuple_method():
     df = pd.DataFrame({"test_column": [1, 2, 3]})
     column_config = SamplerColumnConfig(