REF: remove copy keyword from ensure_foo (pandas-dev#51213)

* REF: remove copy keywd from ensure_foo

* mypy fixup

Author: jbrockmendel

pandas/_libs/algos.pyi

@@ -127,12 +127,12 @@ def diff_2d(
 ) -> None: ...
 def ensure_platform_int(arr: object) -> npt.NDArray[np.intp]: ...
 def ensure_object(arr: object) -> npt.NDArray[np.object_]: ...
-def ensure_float64(arr: object, copy=...) -> npt.NDArray[np.float64]: ...
-def ensure_int8(arr: object, copy=...) -> npt.NDArray[np.int8]: ...
-def ensure_int16(arr: object, copy=...) -> npt.NDArray[np.int16]: ...
-def ensure_int32(arr: object, copy=...) -> npt.NDArray[np.int32]: ...
-def ensure_int64(arr: object, copy=...) -> npt.NDArray[np.int64]: ...
-def ensure_uint64(arr: object, copy=...) -> npt.NDArray[np.uint64]: ...
+def ensure_float64(arr: object) -> npt.NDArray[np.float64]: ...
+def ensure_int8(arr: object) -> npt.NDArray[np.int8]: ...
+def ensure_int16(arr: object) -> npt.NDArray[np.int16]: ...
+def ensure_int32(arr: object) -> npt.NDArray[np.int32]: ...
+def ensure_int64(arr: object) -> npt.NDArray[np.int64]: ...
+def ensure_uint64(arr: object) -> npt.NDArray[np.uint64]: ...
 def take_1d_int8_int8(
     values: np.ndarray, indexer: npt.NDArray[np.intp], out: np.ndarray, fill_value=...
 ) -> None: ...

pandas/_libs/algos_common_helper.pxi.in

@@ -60,14 +60,14 @@ def get_dispatch(dtypes):
 {{for name, c_type, dtype in get_dispatch(dtypes)}}
 
 
-def ensure_{{name}}(object arr, copy=True):
+def ensure_{{name}}(object arr):
     if util.is_array(arr):
         if (<ndarray>arr).descr.type_num == NPY_{{c_type}}:
             return arr
         else:
-            # equiv: arr.astype(np.{{dtype}}, copy=copy)
+            # equiv: arr.astype(np.{{dtype}})
             return cnp.PyArray_Cast(<ndarray>arr, cnp.NPY_{{c_type}})
     else:
-        return np.array(arr, dtype=np.{{dtype}})
+        return np.asarray(arr, dtype=np.{{dtype}})
 
 {{endfor}}

pandas/core/reshape/merge.py

@@ -2149,10 +2149,14 @@ def injection(obj):
             # upcast 'by' parameter because HashTable is limited
             by_type = _get_cython_type_upcast(lbv.dtype)
             by_type_caster = _type_casters[by_type]
-            # error: Cannot call function of unknown type
-            left_by_values = by_type_caster(lbv)  # type: ignore[operator]
-            # error: Cannot call function of unknown type
-            right_by_values = by_type_caster(rbv)  # type: ignore[operator]
+            # error: Incompatible types in assignment (expression has type
+            # "ndarray[Any, dtype[generic]]", variable has type
+            # "List[Union[Union[ExtensionArray, ndarray[Any, Any]], Index, Series]]")
+            left_by_values = by_type_caster(lbv)  # type: ignore[assignment]
+            # error: Incompatible types in assignment (expression has type
+            # "ndarray[Any, dtype[generic]]", variable has type
+            # "List[Union[Union[ExtensionArray, ndarray[Any, Any]], Index, Series]]")
+            right_by_values = by_type_caster(rbv)  # type: ignore[assignment]
 
             # choose appropriate function by type
             func = _asof_by_function(self.direction)