refactor: replace with for better type safety

Replace  bound patterns with Python 3.11+  type for cleaner,
more idiomatic type hints in method returns. Keeps
for Generic classes that need type constraints. This improves type safety
and reduces boilerplate code.

Author: danceratopz

src/ethereum_test_base_types/base_types.py

@@ -21,8 +21,6 @@
     to_number,
 )
 
-N = TypeVar("N", bound="Number")
-
 
 class ToStringSchema:
     """
@@ -44,7 +42,7 @@ def __get_pydantic_core_schema__(
 class Number(int, ToStringSchema):
     """Class that helps represent numbers in tests."""
 
-    def __new__(cls, input_number: NumberConvertible | N):
+    def __new__(cls, input_number: NumberConvertible | Self):
         """Create a new Number object."""
         return super(Number, cls).__new__(cls, to_number(input_number))
 
@@ -57,7 +55,7 @@ def hex(self) -> str:
         return hex(self)
 
     @classmethod
-    def or_none(cls: Type[N], input_number: N | NumberConvertible | None) -> N | None:
+    def or_none(cls: Type[Self], input_number: Self | NumberConvertible | None) -> Self | None:
         """Convert the input to a Number while accepting None."""
         if input_number is None:
             return input_number
@@ -67,7 +65,7 @@ def or_none(cls: Type[N], input_number: N | NumberConvertible | None) -> N | Non
 class Wei(Number):
     """Class that helps represent wei that can be parsed from strings."""
 
-    def __new__(cls, input_number: NumberConvertible | N):
+    def __new__(cls, input_number: NumberConvertible | Self):
         """Create a new Number object."""
         if isinstance(input_number, str):
             words = input_number.split()
@@ -209,9 +207,6 @@ def __get_pydantic_core_schema__(
         )
 
 
-S = TypeVar("S", bound="FixedSizeHexNumber")
-
-
 class FixedSizeHexNumber(int, ToStringSchema):
     """
     A base class that helps represent an integer as a fixed byte-length
@@ -233,7 +228,7 @@ class Sized(cls):  # type: ignore
 
         return Sized
 
-    def __new__(cls, input_number: NumberConvertible | N):
+    def __new__(cls, input_number: NumberConvertible | Self):
         """Create a new Number object."""
         i = to_number(input_number)
         if i > cls.max_value:
@@ -276,9 +271,6 @@ class HashInt(FixedSizeHexNumber[32]):  # type: ignore
     pass
 
 
-T = TypeVar("T", bound="FixedSizeBytes")
-
-
 class FixedSizeBytes(Bytes):
     """Class that helps represent bytes of fixed length in tests."""
 
@@ -296,7 +288,7 @@ class Sized(cls):  # type: ignore
 
     def __new__(
         cls,
-        input_bytes: FixedSizeBytesConvertible | T,
+        input_bytes: FixedSizeBytesConvertible | Self,
         *,
         left_padding: bool = False,
         right_padding: bool = False,
@@ -319,7 +311,9 @@ def __hash__(self) -> int:
         return super(FixedSizeBytes, self).__hash__()
 
     @classmethod
-    def or_none(cls: Type[T], input_bytes: T | FixedSizeBytesConvertible | None) -> T | None:
+    def or_none(
+        cls: Type[Self], input_bytes: Self | FixedSizeBytesConvertible | None
+    ) -> Self | None:
         """Convert the input to a Fixed Size Bytes while accepting None."""
         if input_bytes is None:
             return input_bytes

src/ethereum_test_base_types/pydantic.py

@@ -4,11 +4,10 @@
 
 from pydantic import BaseModel, ConfigDict, RootModel
 from pydantic.alias_generators import to_camel
+from typing_extensions import Self
 
 from .mixins import ModelCustomizationsMixin
 
-Model = TypeVar("Model", bound=BaseModel)
-
 RootModelRootType = TypeVar("RootModelRootType")
 
 
@@ -27,7 +26,7 @@ class EthereumTestRootModel(RootModel[RootModelRootType], ModelCustomizationsMix
 class CopyValidateModel(EthereumTestBaseModel):
     """Model that supports copying with validation."""
 
-    def copy(self: Model, **kwargs) -> Model:
+    def copy(self: Self, **kwargs) -> Self:
         """Create a copy of the model with the updated fields that are validated."""
         return self.__class__(**(self.model_dump(exclude_unset=True) | kwargs))
 

src/ethereum_test_specs/base.py

@@ -5,10 +5,11 @@
 from functools import reduce
 from os import path
 from pathlib import Path
-from typing import Callable, ClassVar, Dict, Generator, List, Sequence, Type, TypeVar
+from typing import Callable, ClassVar, Dict, Generator, List, Sequence, Type
 
 import pytest
 from pydantic import BaseModel, Field, PrivateAttr
+from typing_extensions import Self
 
 from ethereum_clis import Result, TransitionTool
 from ethereum_test_base_types import to_hex
@@ -48,9 +49,6 @@ def verify_result(result: Result, env: Environment):
         assert result.withdrawals_root == to_hex(Withdrawal.list_root(env.withdrawals))
 
 
-T = TypeVar("T", bound="BaseTest")
-
-
 class BaseTest(BaseModel):
     """Represents a base Ethereum test which must return a single test fixture."""
 
@@ -91,11 +89,11 @@ def __pydantic_init_subclass__(cls, **kwargs):
 
     @classmethod
     def from_test(
-        cls: Type[T],
+        cls: Type[Self],
         *,
         base_test: "BaseTest",
         **kwargs,
-    ) -> T:
+    ) -> Self:
         """Create a test in a different format from a base test."""
         new_instance = cls(
             tag=base_test.tag,

src/ethereum_test_types/account_types.py

@@ -7,6 +7,7 @@
 from ethereum_types.bytes import Bytes20
 from ethereum_types.numeric import U256, Bytes32, Uint
 from pydantic import PrivateAttr
+from typing_extensions import Self
 
 from ethereum_test_base_types import (
     Account,
@@ -126,9 +127,9 @@ def get_nonce(self) -> Number:
         self.nonce = Number(nonce + 1)
         return nonce
 
-    def copy(self) -> "EOA":
+    def copy(self) -> Self:
         """Return copy of the EOA."""
-        return EOA(Address(self), key=self.key, nonce=self.nonce)
+        return self.__class__(Address(self), key=self.key, nonce=self.nonce)
 
 
 class Alloc(BaseAlloc):