fix: introduce pydantic v1/v2 code to hanble v1 dataclasses

polyfactory/factories/pydantic_factory.py

@@ -61,9 +61,15 @@
     # is installed.
     from pydantic import PyObject
 
-    # prevent unbound variable warnings
+    # Prevent unbound variable warnings
     BaseModelV2 = BaseModelV1
     UndefinedV2 = Undefined
+
+    if TYPE_CHECKING:
+        from pydantic.dataclasses import Dataclass as PydanticDataclassV1  # pyright: ignore[reportPrivateImportUsage]
+
+        # Prevent unbound variable warnings
+        PydanticDataclassV2 = PydanticDataclassV1
 except ImportError:
     # pydantic v2
 
@@ -92,6 +98,8 @@
     from pydantic.v1.color import Color  # type: ignore[assignment]
     from pydantic.v1.fields import DeferredType, ModelField, Undefined
 
+    if TYPE_CHECKING:
+        from pydantic.dataclasses import PydanticDataclass as PydanticDataclassV2  # pyright: ignore[reportPrivateImportUsage]
 
 if TYPE_CHECKING:
     from collections import abc
@@ -100,7 +108,6 @@
 
     from typing_extensions import NotRequired, TypeGuard
 
-    from pydantic.dataclasses import PydanticDataclass  # pyright: ignore[reportPrivateImportUsage]
 
 ModelT = TypeVar("ModelT", bound="BaseModelV1 | BaseModelV2")  # pyright: ignore[reportInvalidTypeForm]
 T = TypeVar("T")
@@ -627,8 +634,11 @@ def _is_pydantic_v2_model(model: Any) -> TypeGuard[BaseModelV2]:  # pyright: ign
     return not _IS_PYDANTIC_V1 and is_safe_subclass(model, BaseModelV2)
 
 
-def is_pydantic_dataclass(cls: type[Any]) -> TypeGuard[PydanticDataclass]:
-    # This method is available in the `pydantic.dataclasses` module for python >= 3.9
+def _is_pydantic_v1_dataclass(cls: type[Any]) -> TypeGuard[PydanticDataclassV1]:
+    return is_dataclass(cls) and "__pydantic_model__" in cls.__dict__
+
+
+def _is_pydantic_v2_dataclass(cls: type[Any]) -> TypeGuard[PydanticDataclassV2]:
     return is_dataclass(cls) and "__pydantic_validator__" in cls.__dict__
 
 
@@ -639,27 +649,37 @@ class PydanticDataclassFactory(ModelFactory[T]):  # type: ignore[type-var]
 
     @classmethod
     def is_supported_type(cls, value: Any) -> TypeGuard[type[T]]:
-        return is_pydantic_dataclass(value)
+        return _is_pydantic_v1_dataclass(value) or _is_pydantic_v2_dataclass(value)
 
     @classmethod
     def get_model_fields(cls) -> list[FieldMeta]:
-        if not is_pydantic_dataclass(cls.__model__):
+        if _is_pydantic_v1_dataclass(cls.__model__):
+            pydantic_model = cls.__model__.__pydantic_model__
+            cls._fields_metadata = [
+                PydanticFieldMeta.from_model_field(
+                    field,
+                    use_alias=not pydantic_model.__config__.allow_population_by_field_name,  # type: ignore[attr-defined]
+                    random=cls.__random__,
+                )
+                for field in pydantic_model.__fields__.values()
+            ]
+        elif _is_pydantic_v2_dataclass(cls.__model__):
+            pydantic_fields = cls.__model__.__pydantic_fields__
+            pydantic_config = cls.__model__.__pydantic_config__
+            cls._fields_metadata = [
+                PydanticFieldMeta.from_field_info(
+                    field_info=field_info,
+                    field_name=field_name,
+                    random=cls.__random__,
+                    use_alias=not pydantic_config.get(
+                        "populate_by_name",
+                        False,
+                    ),
+                )
+                for field_name, field_info in pydantic_fields.items()
+            ]
+        else:
             # This should be unreachable
             return []
 
-        pydantic_fields = cls.__model__.__pydantic_fields__
-        pydantic_config = cls.__model__.__pydantic_config__
-        cls._fields_metadata = [
-            PydanticFieldMeta.from_field_info(
-                field_info=field_info,
-                field_name=field_name,
-                random=cls.__random__,
-                use_alias=not pydantic_config.get(
-                    "populate_by_name",
-                    False,
-                ),
-            )
-            for field_name, field_info in pydantic_fields.items()
-        ]
-
         return cls._fields_metadata