TYP: ExtensionDtype.name/type as ClassVar (#54458)

* TYP:ExtensionDtype.name/type as ClassVar * no code changes; only .name

Author: twoertwein

pandas/core/arrays/boolean.py

@@ -3,6 +3,7 @@
 import numbers
 from typing import (
  TYPE_CHECKING,
+ ClassVar,
  cast,
 )
 
@@ -60,7 +61,7 @@ class BooleanDtype(BaseMaskedDtype):
  BooleanDtype
  """
 
- name = "boolean"
+ name: ClassVar[str] = "boolean"
 
  # https://github.com/python/mypy/issues/4125
  # error: Signature of "type" incompatible with supertype "BaseMaskedDtype"

pandas/core/arrays/floating.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from typing import ClassVar
+
 import numpy as np
 
 from pandas.core.dtypes.base import register_extension_dtype
@@ -156,14 +158,14 @@ class FloatingArray(NumericArray):
 @register_extension_dtype
 class Float32Dtype(FloatingDtype):
  type = np.float32
- name = "Float32"
+ name: ClassVar[str] = "Float32"
  __doc__ = _dtype_docstring.format(dtype="float32")
 
 
 @register_extension_dtype
 class Float64Dtype(FloatingDtype):
  type = np.float64
- name = "Float64"
+ name: ClassVar[str] = "Float64"
  __doc__ = _dtype_docstring.format(dtype="float64")
 
 

pandas/core/arrays/integer.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from typing import ClassVar
+
 import numpy as np
 
 from pandas.core.dtypes.base import register_extension_dtype
@@ -205,56 +207,56 @@ class IntegerArray(NumericArray):
 @register_extension_dtype
 class Int8Dtype(IntegerDtype):
  type = np.int8
- name = "Int8"
+ name: ClassVar[str] = "Int8"
  __doc__ = _dtype_docstring.format(dtype="int8")
 
 
 @register_extension_dtype
 class Int16Dtype(IntegerDtype):
  type = np.int16
- name = "Int16"
+ name: ClassVar[str] = "Int16"
  __doc__ = _dtype_docstring.format(dtype="int16")
 
 
 @register_extension_dtype
 class Int32Dtype(IntegerDtype):
  type = np.int32
- name = "Int32"
+ name: ClassVar[str] = "Int32"
  __doc__ = _dtype_docstring.format(dtype="int32")
 
 
 @register_extension_dtype
 class Int64Dtype(IntegerDtype):
  type = np.int64
- name = "Int64"
+ name: ClassVar[str] = "Int64"
  __doc__ = _dtype_docstring.format(dtype="int64")
 
 
 @register_extension_dtype
 class UInt8Dtype(IntegerDtype):
  type = np.uint8
- name = "UInt8"
+ name: ClassVar[str] = "UInt8"
  __doc__ = _dtype_docstring.format(dtype="uint8")
 
 
 @register_extension_dtype
 class UInt16Dtype(IntegerDtype):
  type = np.uint16
- name = "UInt16"
+ name: ClassVar[str] = "UInt16"
  __doc__ = _dtype_docstring.format(dtype="uint16")
 
 
 @register_extension_dtype
 class UInt32Dtype(IntegerDtype):
  type = np.uint32
- name = "UInt32"
+ name: ClassVar[str] = "UInt32"
  __doc__ = _dtype_docstring.format(dtype="uint32")
 
 
 @register_extension_dtype
 class UInt64Dtype(IntegerDtype):
  type = np.uint64
- name = "UInt64"
+ name: ClassVar[str] = "UInt64"
  __doc__ = _dtype_docstring.format(dtype="uint64")
 
 

pandas/core/arrays/string_.py

@@ -2,6 +2,7 @@
 
 from typing import (
  TYPE_CHECKING,
+ ClassVar,
  Literal,
 )
 
@@ -96,7 +97,9 @@ class StringDtype(StorageExtensionDtype):
  string[pyarrow]
  """
 
- name = "string"
+ # error: Cannot override instance variable (previously declared on
+ # base class "StorageExtensionDtype") with class variable
+ name: ClassVar[str] = "string" # type: ignore[misc]
 
  #: StringDtype().na_value uses pandas.NA
  @property

pandas/core/dtypes/dtypes.py

@@ -1517,7 +1517,6 @@ class BaseMaskedDtype(ExtensionDtype):
  Base class for dtypes for BaseMaskedArray subclasses.
  """
 
- name: str
  base = None
  type: type