REF: remove copy keywd from ensure_foo

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}}