feat(python): Improved error message on invalid Python Enum init (#20060)

Author: alexander-beedie

py-polars/polars/convert/general.py

@@ -782,7 +782,7 @@ def _from_series_repr(m: re.Match[str]) -> Series:
     else:
         string_values = [
             v.strip()
-            for v in re.findall(r"[\s>#]*(?:\t|\s{4,})([^\n]*)\n", m.groups()[-1])
+            for v in re.findall(r"[\s>#]*(?:\t|\s{2,})([^\n]*)\n", m.groups()[-1])
         ]
         if string_values == ["[", "]"]:
             string_values = []

py-polars/polars/datatypes/classes.py

@@ -622,10 +622,10 @@ def __init__(self, categories: Series | Iterable[str] | type[enum.Enum]) -> None
         )
 
         if isclass(categories) and issubclass(categories, enum.Enum):
-            for enum_subclass in (enum.IntFlag, enum.Flag, enum.IntEnum):
+            for enum_subclass in (enum.Flag, enum.IntEnum):
                 if issubclass(categories, enum_subclass):
-                    enum_type_name = enum_subclass.__name__
-                    msg = f"Enum categories must be strings; Python `enum.{enum_type_name}` values are integers"
+                    enum_type_name = categories.__name__
+                    msg = f"Enum categories must be strings; `{enum_type_name}` values are integers"
                     raise TypeError(msg)
 
             enum_values = [

py-polars/tests/unit/datatypes/test_enum.py

@@ -94,11 +94,9 @@ class Color(EnumBase):  # type: ignore[no-redef,misc,valid-type]
             GREEN = enum.auto()
             BLUE = enum.auto()
 
-        base_name = EnumBase.__name__
-
         with pytest.raises(
             TypeError,
-            match=f"Enum categories must be strings; Python `enum.{base_name}` values are integers",
+            match="Enum categories must be strings; `Color` values are integers",
         ):
             pl.Enum(Color)