removed unnecessary generic parameters from Ok and Err. WIP

poltergeist/result.py

@@ -8,7 +8,7 @@
 
 @final
 @dataclass(repr=False, frozen=True, slots=True)
-class Ok(Generic[T, E]):
+class Ok(Generic[T]):
     _value: T
 
     def __repr__(self) -> str:
@@ -31,13 +31,13 @@ def unwrap_or(self, default: DefaultT) -> T:
     def unwrap_or(self, default: Any = None) -> Any:
         return self.unwrap()
 
-    def unwrap_or_else(self, op: Callable[[E], DefaultT]) -> T:
+    def unwrap_or_else(self, op: NoReturn) -> T:
         return self.unwrap()
 
 
 @final
 @dataclass(repr=False, eq=False, frozen=True, slots=True)
-class Err(Generic[T, E]):
+class Err(Generic[E]):
     _err: E
 
     def __repr__(self) -> str:
@@ -71,4 +71,4 @@ def __eq__(self, __o: Any) -> bool:
         )
 
 
-Result = Ok[T, E] | Err[T, E]
+Result = Ok[T] | Err[E]

tests/mypy/test_decorator.yml

@@ -5,7 +5,7 @@
     @poltergeist
     def test(a: int, b: str) -> float | None: ...
 
-    reveal_type(test)  # N: Revealed type is "def (a: builtins.int, b: builtins.str) -> Union[poltergeist.result.Ok[Union[builtins.float, None], builtins.Exception], poltergeist.result.Err[Union[builtins.float, None], builtins.Exception]]"
+    reveal_type(test)  # N: Revealed type is "def (a: builtins.int, b: builtins.str) -> Union[poltergeist.result.Ok[Union[builtins.float, None]], poltergeist.result.Err[builtins.Exception]]"
 
 - case: decorator_default
   main: |
@@ -14,7 +14,7 @@
     @poltergeist()
     def test(a: int, b: str) -> float | None: ...
 
-    reveal_type(test)  # N: Revealed type is "def (a: builtins.int, b: builtins.str) -> Union[poltergeist.result.Ok[Union[builtins.float, None], builtins.Exception], poltergeist.result.Err[Union[builtins.float, None], builtins.Exception]]"
+    reveal_type(test)  # N: Revealed type is "def (a: builtins.int, b: builtins.str) -> Union[poltergeist.result.Ok[Union[builtins.float, None]], poltergeist.result.Err[builtins.Exception]]"
 
 - case: decorator_with_args
   main: |
@@ -23,7 +23,7 @@
     @poltergeist(error=ValueError)
     def test(a: int, b: str) -> float | None: ...
 
-    reveal_type(test)  # N: Revealed type is "def (a: builtins.int, b: builtins.str) -> Union[poltergeist.result.Ok[Union[builtins.float, None], builtins.ValueError], poltergeist.result.Err[Union[builtins.float, None], builtins.ValueError]]"
+    reveal_type(test)  # N: Revealed type is "def (a: builtins.int, b: builtins.str) -> Union[poltergeist.result.Ok[Union[builtins.float, None]], poltergeist.result.Err[builtins.ValueError]]"
 
 - case: decorator_invalid_error_type
   main: |
@@ -34,6 +34,6 @@
   out: |
     main:3: error: No overload variant of "poltergeist" matches argument type "int"  [call-overload]
     main:3: note: Possible overload variants:
-    main:3: note:     def [P`-1, T] poltergeist(Callable[P, T], /) -> Callable[P, Union[Ok[T, Exception], Err[T, Exception]]]
-    main:3: note:     def poltergeist() -> Callable[[Callable[P, T]], Callable[P, Union[Ok[T, Exception], Err[T, Exception]]]]
-    main:3: note:     def [E <: BaseException] poltergeist(*, error: Type[E]) -> Callable[[Callable[P, T]], Callable[P, Union[Ok[T, E], Err[T, E]]]]
+    main:3: note:     def [P`-1, T] poltergeist(Callable[P, T], /) -> Callable[P, Union[Ok[T], Err[Exception]]]
+    main:3: note:     def poltergeist() -> Callable[[Callable[P, T]], Callable[P, Union[Ok[T], Err[Exception]]]]
+    main:3: note:     def [E <: BaseException] poltergeist(*, error: Type[E]) -> Callable[[Callable[P, T]], Callable[P, Union[Ok[T], Err[E]]]]

tests/mypy/test_err.yml

@@ -1,33 +1,33 @@
 - case: err_generic
   main: |
     from poltergeist import Err
-    instance: Err[str, Exception] = Err(123)  # E: Argument 1 to "Err" has incompatible type "int"; expected "Exception"  [arg-type]
-    other: Err[str, int]  # E: Type argument "int" of "Err" must be a subtype of "BaseException"  [type-var]
+    instance: Err[Exception] = Err(123)  # E: Argument 1 to "Err" has incompatible type "int"; expected "Exception"  [arg-type]
+    other: Err[int]  # E: Type argument "int" of "Err" must be a subtype of "BaseException"  [type-var]
 
 - case: err_err
   main: |
     from poltergeist import Err
-    instance: Err[str, Exception]
+    instance: Err[Exception]
     reveal_type(instance.err())  # N: Revealed type is "builtins.Exception"
 
 - case: err_unwrap
   main: |
     from poltergeist import Err
-    instance: Err[str, Exception]
+    instance: Err[Exception]
     reveal_type(instance.unwrap())  # N: Revealed type is "<nothing>"
 
 - case: err_unwrap_or
   main: |
     from poltergeist import Err
-    instance: Err[str, Exception]
+    instance: Err[Exception]
     reveal_type(instance.unwrap_or())  # N: Revealed type is "None"
     reveal_type(instance.unwrap_or(123))  # N: Revealed type is "builtins.int"
     reveal_type(instance.unwrap_or("abc"))  # N: Revealed type is "builtins.str"
 
 - case: err_unwrap_or_else
   main: |
     from poltergeist import Err
-    instance: Err[str, Exception]
+    instance: Err[Exception]
     reveal_type(instance.unwrap_or_else(lambda e: e))  # N: Revealed type is "builtins.Exception"
     instance.unwrap_or_else(123)  # E: Argument 1 to "unwrap_or_else" of "Err" has incompatible type "int"; expected "Callable[[Exception], <nothing>]"  [arg-type]
     default: str = instance.unwrap_or_else(lambda e: e)  # E: Incompatible types in assignment (expression has type "Exception", variable has type "str")  [assignment]

tests/mypy/test_ok.yml

@@ -1,32 +1,33 @@
 - case: ok_generic
   main: |
     from poltergeist import Ok
-    instance: Ok[str, Exception] = Ok(123)  # E: Argument 1 to "Ok" has incompatible type "int"; expected "str"  [arg-type]
-    other: Ok[str, int]  # E: Type argument "int" of "Ok" must be a subtype of "BaseException"  [type-var]
+    instance: Ok[str] = Ok(123)  # E: Argument 1 to "Ok" has incompatible type "int"; expected "str"  [arg-type]
 
 - case: ok_err
   main: |
     from poltergeist import Ok
-    instance: Ok[str, Exception]
+    instance: Ok[str]
     reveal_type(instance.err())  # N: Revealed type is "None"
 
 - case: ok_unwrap
   main: |
     from poltergeist import Ok
-    instance: Ok[str, Exception]
+    instance: Ok[str]
     reveal_type(instance.unwrap())  # N: Revealed type is "builtins.str"
 
 - case: ok_unwrap_or
   main: |
     from poltergeist import Ok
-    instance: Ok[str, Exception]
+    instance: Ok[str]
     reveal_type(instance.unwrap_or())  # N: Revealed type is "builtins.str"
     reveal_type(instance.unwrap_or(123))  # N: Revealed type is "builtins.str"
     reveal_type(instance.unwrap_or("abc"))  # N: Revealed type is "builtins.str"
 
 - case: ok_unwrap_or_else
   main: |
     from poltergeist import Ok
-    instance: Ok[str, Exception]
-    reveal_type(instance.unwrap_or_else(lambda e: e))  # N: Revealed type is "builtins.str"
-    instance.unwrap_or_else(123)  # E: Argument 1 to "unwrap_or_else" of "Ok" has incompatible type "int"; expected "Callable[[Exception], <nothing>]"  [arg-type]
+    instance: Ok[str]
+    reveal_type(instance.unwrap_or_else(lambda e: e))
+  out: |
+    main:3: note: Revealed type is "builtins.str"
+    main:3: error: Argument 1 to "unwrap_or_else" of "Ok" has incompatible type "Callable[[Any], Any]"; expected "NoReturn"  [arg-type]

tests/mypy/test_result.yml

@@ -3,10 +3,7 @@
     from poltergeist import Result, Ok, Err
     ok: Result[str, Exception] = Ok(123)  # E: Argument 1 to "Ok" has incompatible type "int"; expected "str"  [arg-type]
     err: Result[str, Exception] = Err(123)  # E: Argument 1 to "Err" has incompatible type "int"; expected "Exception"  [arg-type]
-    other: Result[str, int]
-  out: |
-    main:4: error: Type argument "int" of "Ok" must be a subtype of "BaseException"  [type-var]
-    main:4: error: Type argument "int" of "Err" must be a subtype of "BaseException"  [type-var]
+    other: Result[str, int]  # E: Type argument "int" of "Err" must be a subtype of "BaseException"  [type-var]
 
 - case: result_err
   main: |
@@ -36,5 +33,5 @@
     default: str = instance.unwrap_or_else(lambda e: e)  # E: Incompatible types in assignment (expression has type "Union[str, Exception]", variable has type "str")  [assignment]
     instance.unwrap_or_else(123)
   out: |
-    main:5: error: Argument 1 to "unwrap_or_else" of "Ok" has incompatible type "int"; expected "Callable[[Exception], <nothing>]"  [arg-type]
+    main:5: error: Argument 1 to "unwrap_or_else" of "Ok" has incompatible type "int"; expected "NoReturn"  [arg-type]
     main:5: error: Argument 1 to "unwrap_or_else" of "Err" has incompatible type "int"; expected "Callable[[Exception], <nothing>]"  [arg-type]

tests/test_result.py

@@ -4,7 +4,7 @@
 
 
 def test_ok() -> None:
-    result: Result[str, Exception] = Ok("abc")
+    result = Ok("abc")
 
     match result:
         case Ok(v):
@@ -24,15 +24,15 @@ def test_ok() -> None:
 
 
 def test_ok_eq() -> None:
-    result: Result[str, Exception] = Ok("abc")
+    result = Ok("abc")
     assert result == Ok("abc")
     assert result != Ok("aaa")
     assert result != Err(Exception("abc"))
     assert result != "abc"
 
 
 def test_error() -> None:
-    result: Result[str, ValueError] = Err(ValueError("abc"))
+    result = Err(ValueError("abc"))
 
     match result:
         case Err(e):
@@ -58,7 +58,7 @@ def test_error() -> None:
 
 
 def test_err_eq() -> None:
-    result: Result[str, ValueError] = Err(ValueError("abc"))
+    result = Err(ValueError("abc"))
     assert result == Err(ValueError("abc"))
     assert result != Err(ValueError("aaa"))
     assert result != Err(ValueError("abc", 1))