refactor: repair type hints for generics

pyproject.toml

@@ -36,6 +36,7 @@ mypy = "^1.0.0"
 nox = "^2022.1.7"
 pre-commit = "^2.17"
 pre-commit-hooks = "^4.1"
+pylint = "^3.2.0"
 pytest = "^7"
 pytest-cov = "^4"
 python-semantic-release = "^8.0.8"

src/bin/install.sh

@@ -11,7 +11,9 @@ function install_git_hooks () {
 
 function install_poetry () {
   if [ -z ${POETRY} ]; then
-    curl -sSL https://install.python-poetry.org/ | python
+    # FIXME ED The poetry installer is pinned to version 1.8.5, because the 2.0.0
+    #          release breaks the build. We need to support 2.0.0 in the future though.
+    curl -sSL https://install.python-poetry.org/ |  POETRY_VERSION=1.8.5 python -
 
     try_source_env
   fi

src/pyella/either.py

@@ -215,7 +215,7 @@ def discard(
 
 def replace(
     self, value: TC_co  # type: ignore [misc] # covariant arg ok, b/c function is pure
-) -> Either[TA_co, TC_co]:
+) -> Either[TA_co, TC_co]:  # type: ignore [misc] # TA_co only appears once use object, b/c chaining will break
     """
     Replace the value of an :py:class:`Either` with a new value
 
@@ -267,7 +267,11 @@ def map_left(
 
     .. note:: Haskell: `first <https://hackage.haskell.org/package/base/docs/Data-Either.html#v:first>`_
     """
-    return either(lambda e: left(apply(e)), right, em0)
+
+    def right_type_helper(value: TB_co) -> Either[TC_co, TB_co]:  # type: ignore [misc] # covariant arg ok, b/c function is pure
+        return right(value)
+
+    return either(lambda e: left(apply(e)), right_type_helper, em0)
 
 
 def if_left(
@@ -334,14 +338,14 @@ def rights(eithers: Iterable[Either[TA_co, TB_co]]) -> List[TB_co]:
 
 def left(
     value: TA_co,  # type: ignore [misc] # covariant arg ok, b/c function is pure
-) -> Left[TA_co, TB_co]:
+) -> Left[TA_co, TB_co]:  # type: ignore [misc] # TB_co only appears once use object, b/c chaining will break
     "Create a :py:class:`Left[TA] <Left>` with the given value"
-    return Left(value)
+    return Left[TA_co, TB_co](value)
 
 
 def right(
     value: TB_co,  # type: ignore [misc] # covariant arg ok, b/c function is pure
-) -> Right[TA_co, TB_co]:
+) -> Right[TA_co, TB_co]:  # type: ignore [misc] # TA_co only appears once use object, b/c chaining will break
     "Alias for :py:func:`pure(value) <pure>`"
     return pure(value)
 

src/tests/test_either.py

@@ -39,7 +39,7 @@ def _m_square(value: int) -> Either[str, int]:
 
 
 # pylint: disable=unused-argument
-def _m_fail(value: int) -> Either[str, int]:
+def _m_fail(_: int) -> Either[str, int]:
     return left(random_str())
 
 
@@ -104,10 +104,18 @@ def test_creation_of_either_with_right_returns_expected_results(self):
         # arrange
         some_random_value = random_int()
 
+        def right_type_helper(value: int) -> Either[str, int]:
+            return right(value)
+
+        def pure_type_helper(  # pylint: disable=unused-argument
+            value: int,
+        ) -> Either[str, int]:
+            return pure(value)
+
         right_initializers: List[Callable[[int], Either[str, int]]] = [
             Right,
-            right,
-            pure,
+            right_type_helper,
+            pure_type_helper,
         ]
 
         # act
@@ -137,7 +145,13 @@ def test_creation_of_either_with_left_returns_expected_results(self):
         # arrange
         some_random_left_value = random_str()
 
-        left_initializers: List[Callable[[str], Either[str, int]]] = [Left, left]
+        def left_type_helper(value: str) -> Either[str, int]:
+            return left(value)
+
+        left_initializers: List[Callable[[str], Either[str, int]]] = [
+            Left,
+            left_type_helper,
+        ]
 
         # act
         results: List[Either[str, int]] = list(