Upgrade mypy. (#8302)

Some breaking changes were made in mypy.

python-package/xgboost/_typing.py

@@ -1,7 +1,18 @@
+# pylint: disable=protected-access
 """Shared typing definition."""
 import ctypes
 import os
-from typing import Any, Callable, Dict, List, Sequence, Type, TypeVar, Union
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Callable,
+    Dict,
+    List,
+    Sequence,
+    Type,
+    TypeVar,
+    Union,
+)
 
 # os.PathLike/string/numpy.array/scipy.sparse/pd.DataFrame/dt.Frame/
 # cudf.DataFrame/cupy.array/dlpack
@@ -32,14 +43,15 @@
 # c_bst_ulong corresponds to bst_ulong defined in xgboost/c_api.h
 c_bst_ulong = ctypes.c_uint64  # pylint: disable=C0103
 
-CTypeT = Union[
+CTypeT = TypeVar(
+    "CTypeT",
     ctypes.c_void_p,
     ctypes.c_char_p,
     ctypes.c_int,
     ctypes.c_float,
     ctypes.c_uint,
     ctypes.c_size_t,
-]
+)
 
 # supported numeric types
 CNumeric = Union[
@@ -52,21 +64,36 @@
 ]
 
 # c pointer types
-# real type should be, as defined in typeshed
-# but this has to be put in a .pyi file
-# c_str_ptr_t = ctypes.pointer[ctypes.c_char]
-CStrPtr = ctypes.pointer
-# c_str_pptr_t = ctypes.pointer[ctypes.c_char_p]
-CStrPptr = ctypes.pointer
-# c_float_ptr_t = ctypes.pointer[ctypes.c_float]
-CFloatPtr = ctypes.pointer
-
-# c_numeric_ptr_t = Union[
-#  ctypes.pointer[ctypes.c_float], ctypes.pointer[ctypes.c_double],
-#  ctypes.pointer[ctypes.c_uint], ctypes.pointer[ctypes.c_uint64],
-#  ctypes.pointer[ctypes.c_int32], ctypes.pointer[ctypes.c_int64]
-# ]
-CNumericPtr = ctypes.pointer
+if TYPE_CHECKING:
+    CStrPtr = ctypes._Pointer[ctypes.c_char]
+
+    CStrPptr = ctypes._Pointer[ctypes.c_char_p]
+
+    CFloatPtr = ctypes._Pointer[ctypes.c_float]
+
+    CNumericPtr = Union[
+        ctypes._Pointer[ctypes.c_float],
+        ctypes._Pointer[ctypes.c_double],
+        ctypes._Pointer[ctypes.c_uint],
+        ctypes._Pointer[ctypes.c_uint64],
+        ctypes._Pointer[ctypes.c_int32],
+        ctypes._Pointer[ctypes.c_int64],
+    ]
+else:
+    CStrPtr = ctypes._Pointer
+
+    CStrPptr = ctypes._Pointer
+
+    CFloatPtr = ctypes._Pointer
+
+    CNumericPtr = Union[
+        ctypes._Pointer,
+        ctypes._Pointer,
+        ctypes._Pointer,
+        ctypes._Pointer,
+        ctypes._Pointer,
+        ctypes._Pointer,
+    ]
 
 # template parameter
 _T = TypeVar("_T")

python-package/xgboost/core.py

@@ -99,9 +99,9 @@ def from_cstr_to_pystr(data: CStrPptr, length: c_bst_ulong) -> List[str]:
     res = []
     for i in range(length.value):
         try:
-            res.append(str(data[i].decode('ascii')))  # type: ignore
+            res.append(str(cast(bytes, data[i]).decode('ascii')))
         except UnicodeDecodeError:
-            res.append(str(data[i].decode('utf-8')))  # type: ignore
+            res.append(str(cast(bytes, data[i]).decode('utf-8')))
     return res
 
 
@@ -381,7 +381,7 @@ def ctypes2buffer(cptr: CStrPtr, length: int) -> bytearray:
         raise RuntimeError('expected char pointer')
     res = bytearray(length)
     rptr = (ctypes.c_char * length).from_buffer(res)
-    if not ctypes.memmove(rptr, cptr, length):  # type: ignore
+    if not ctypes.memmove(rptr, cptr, length):
         raise RuntimeError('memmove failed')
     return res
 
@@ -393,8 +393,8 @@ def c_str(string: str) -> ctypes.c_char_p:
 
 def c_array(
     ctype: Type[CTypeT], values: ArrayLike
-) -> Union[ctypes.Array, ctypes.pointer]:
-    """Convert a python string to c array."""
+) -> Union[ctypes.Array, ctypes._Pointer]:
+    """Convert a python array to c array."""
     if isinstance(values, np.ndarray) and values.dtype.itemsize == ctypes.sizeof(ctype):
         return values.ctypes.data_as(ctypes.POINTER(ctype))
     return (ctype * len(values))(*values)

python-package/xgboost/training.py

@@ -13,7 +13,7 @@
 from .core import Booster, DMatrix, XGBoostError, _deprecate_positional_args
 from .core import Metric, Objective
 from .compat import SKLEARN_INSTALLED, XGBStratifiedKFold, DataFrame
-from ._typing import _F, FPreProcCallable, BoosterParam
+from ._typing import Callable, FPreProcCallable, BoosterParam
 
 _CVFolds = Sequence["CVPack"]
 
@@ -205,10 +205,10 @@ def __init__(self, dtrain: DMatrix, dtest: DMatrix, param: Optional[Union[Dict,
         self.watchlist = [(dtrain, 'train'), (dtest, 'test')]
         self.bst = Booster(param, [dtrain, dtest])
 
-    def __getattr__(self, name: str) -> _F:
+    def __getattr__(self, name: str) -> Callable:
         def _inner(*args: Any, **kwargs: Any) -> Any:
             return getattr(self.bst, name)(*args, **kwargs)
-        return cast(_F, _inner)
+        return _inner
 
     def update(self, iteration: int, fobj: Optional[Objective]) -> None:
         """"Update the boosters for one iteration"""

tests/ci_build/conda_env/python_lint.yml

@@ -6,7 +6,7 @@ dependencies:
 - pylint
 - wheel
 - setuptools
-- mypy=0.961
+- mypy>=0.981
 - numpy
 - scipy
 - pandas