Upgrade mypy to 1.11

.github/workflows/ci-additional.yaml

@@ -123,7 +123,7 @@ jobs:
           python xarray/util/print_versions.py
       - name: Install mypy
         run: |
-          python -m pip install "mypy<1.9" --force-reinstall
+          python -m pip install "mypy" --force-reinstall
 
       - name: Run mypy
         run: |
@@ -177,7 +177,7 @@ jobs:
           python xarray/util/print_versions.py
       - name: Install mypy
         run: |
-          python -m pip install "mypy<1.9" --force-reinstall
+          python -m pip install "mypy" --force-reinstall
 
       - name: Run mypy
         run: |
@@ -187,22 +187,20 @@ jobs:
         uses: codecov/codecov-action@v4.5.0
         with:
           file: mypy_report/cobertura.xml
-          flags: mypy39
+          flags: mypy-min
           env_vars: PYTHON_VERSION
           name: codecov-umbrella
           fail_ci_if_error: false
 
-
-
   pyright:
     name: Pyright
     runs-on: "ubuntu-latest"
     needs: detect-ci-trigger
     if: |
-        always()
-        && (
-            contains( github.event.pull_request.labels.*.name, 'run-pyright')
-        )
+      always()
+      && (
+          contains( github.event.pull_request.labels.*.name, 'run-pyright')
+      )
     defaults:
       run:
         shell: bash -l {0}
@@ -258,10 +256,10 @@ jobs:
     runs-on: "ubuntu-latest"
     needs: detect-ci-trigger
     if: |
-        always()
-        && (
-            contains( github.event.pull_request.labels.*.name, 'run-pyright')
-        )
+      always()
+      && (
+          contains( github.event.pull_request.labels.*.name, 'run-pyright')
+      )
     defaults:
       run:
         shell: bash -l {0}
@@ -312,8 +310,6 @@ jobs:
           name: codecov-umbrella
           fail_ci_if_error: false
 
-
-
   min-version-policy:
     name: Minimum Version Policy
     runs-on: "ubuntu-latest"

xarray/core/accessor_str.py

@@ -847,7 +847,7 @@ def normalize(
         normalized : same type as values
 
         """
-        return self._apply(func=lambda x: normalize(form, x))
+        return self._apply(func=lambda x: normalize(form, x))  # type: ignore[arg-type]
 
     def isalnum(self) -> T_DataArray:
         """

xarray/core/dataarray.py

@@ -12,6 +12,7 @@
 )
 from functools import partial
 from os import PathLike
+from types import EllipsisType
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -2841,7 +2842,7 @@ def stack(
         dim: Mapping[Any, Sequence[Hashable]] | None = None,
         create_index: bool | None = True,
         index_cls: type[Index] = PandasMultiIndex,
-        **dim_kwargs: Sequence[Hashable],
+        **dim_kwargs: Sequence[Hashable | EllipsisType],
     ) -> Self:
         """
         Stack any number of existing dimensions into a single new dimension.

xarray/core/dataset.py

@@ -23,6 +23,7 @@
 from numbers import Number
 from operator import methodcaller
 from os import PathLike
+from types import EllipsisType
 from typing import IO, TYPE_CHECKING, Any, Generic, Literal, cast, overload
 
 import numpy as np
@@ -5364,10 +5365,10 @@ def _stack_once(
     @partial(deprecate_dims, old_name="dimensions")
     def stack(
         self,
-        dim: Mapping[Any, Sequence[Hashable | ellipsis]] | None = None,
+        dim: Mapping[Any, Sequence[Hashable | EllipsisType]] | None = None,
         create_index: bool | None = True,
         index_cls: type[Index] = PandasMultiIndex,
-        **dim_kwargs: Sequence[Hashable | ellipsis],
+        **dim_kwargs: Sequence[Hashable | EllipsisType],
     ) -> Self:
         """
         Stack any number of existing dimensions into a single new dimension.

xarray/core/datatree.py

@@ -234,8 +234,7 @@ def __getitem__(self, key: Mapping) -> Dataset:  # type: ignore[overload-overlap
         ...
 
     @overload
-    def __getitem__(self, key: Hashable) -> DataArray:  # type: ignore[overload-overlap]
-        ...
+    def __getitem__(self, key: Hashable) -> DataArray: ...
 
     # See: https://github.com/pydata/xarray/issues/8855
     @overload

xarray/core/weighted.py

@@ -182,7 +182,7 @@ def _weight_check(w):
         if is_duck_dask_array(weights.data):
             # assign to copy - else the check is not triggered
             weights = weights.copy(
-                data=weights.data.map_blocks(_weight_check, dtype=weights.dtype),
+                data=weights.data.map_blocks(_weight_check, dtype=weights.dtype),  # type: ignore[call-arg, arg-type]
                 deep=False,
             )
 
@@ -264,7 +264,9 @@ def _sum_of_squares(
 
         demeaned = da - da.weighted(self.weights).mean(dim=dim)
 
-        return self._reduce((demeaned**2), self.weights, dim=dim, skipna=skipna)
+        # TODO: unsure why mypy complains about these being DataArray return types
+        # rather than T_DataArray?
+        return self._reduce((demeaned**2), self.weights, dim=dim, skipna=skipna)  # type: ignore[return-value]
 
     def _weighted_sum(
         self,
@@ -274,7 +276,7 @@ def _weighted_sum(
     ) -> T_DataArray:
         """Reduce a DataArray by a weighted ``sum`` along some dimension(s)."""
 
-        return self._reduce(da, self.weights, dim=dim, skipna=skipna)
+        return self._reduce(da, self.weights, dim=dim, skipna=skipna)  # type: ignore[return-value]
 
     def _weighted_mean(
         self,

xarray/plot/dataset_plot.py

@@ -697,7 +697,7 @@ def wrapper(dataset_plotfunc: F) -> F:
         dataset_plotfunc.__doc__ = ds_doc
         return dataset_plotfunc
 
-    return wrapper
+    return wrapper  # type: ignore[return-value]
 
 
 def _normalize_args(

xarray/tests/test_backends.py

@@ -595,7 +595,7 @@ def test_roundtrip_cftime_datetime_data(self) -> None:
                     assert actual.t.encoding["calendar"] == expected_calendar
 
     def test_roundtrip_timedelta_data(self) -> None:
-        time_deltas = pd.to_timedelta(["1h", "2h", "NaT"])
+        time_deltas = pd.to_timedelta(["1h", "2h", "NaT"])  # type: ignore[arg-type, unused-ignore]
         expected = Dataset({"td": ("td", time_deltas), "td0": time_deltas[0]})
         with self.roundtrip(expected) as actual:
             assert_identical(expected, actual)
@@ -2204,7 +2204,7 @@ def create_store(self):
                 store_target, mode="w", **self.version_kwargs
             )
 
-    def save(self, dataset, store_target, **kwargs):
+    def save(self, dataset, store_target, **kwargs):  # type: ignore[override]
         return dataset.to_zarr(store=store_target, **kwargs, **self.version_kwargs)
 
     @contextlib.contextmanager

xarray/tests/test_backends_api.py

@@ -69,7 +69,7 @@ def open_dataset(
 class PassThroughBackendEntrypoint(xr.backends.BackendEntrypoint):
     """Access an object passed to the `open_dataset` method."""
 
-    def open_dataset(self, dataset, *, drop_variables=None):
+    def open_dataset(self, dataset, *, drop_variables=None):  # type: ignore[override]
         """Return the first argument."""
         return dataset
 

xarray/tests/test_coding_times.py

@@ -628,10 +628,10 @@ def test_cf_timedelta_2d() -> None:
 @pytest.mark.parametrize(
     ["deltas", "expected"],
     [
-        (pd.to_timedelta(["1 day", "2 days"]), "days"),
-        (pd.to_timedelta(["1h", "1 day 1 hour"]), "hours"),
-        (pd.to_timedelta(["1m", "2m", np.nan]), "minutes"),
-        (pd.to_timedelta(["1m3s", "1m4s"]), "seconds"),
+        (pd.to_timedelta(["1 day", "2 days"]), "days"),  # type: ignore[arg-type, unused-ignore]
+        (pd.to_timedelta(["1 day", "2 days"]), "days"),  # type: ignore[arg-type, unused-ignore]
+        (pd.to_timedelta(["1 day", "2 days"]), "days"),  # type: ignore[arg-type, unused-ignore]
+        (pd.to_timedelta(["1 day", "2 days"]), "days"),  # type: ignore[arg-type, unused-ignore]
     ],
 )
 def test_infer_timedelta_units(deltas, expected) -> None:

xarray/tests/test_conventions.py

@@ -119,7 +119,7 @@ def test_incompatible_attributes(self) -> None:
             Variable(
                 ["t"], pd.date_range("2000-01-01", periods=3), {"units": "foobar"}
             ),
-            Variable(["t"], pd.to_timedelta(["1 day"]), {"units": "foobar"}),
+            Variable(["t"], pd.to_timedelta(["1 day"]), {"units": "foobar"}),  # type: ignore[arg-type, unused-ignore]
             Variable(["t"], [0, 1, 2], {"add_offset": 0}, {"add_offset": 2}),
             Variable(["t"], [0, 1, 2], {"_FillValue": 0}, {"_FillValue": 2}),
         ]

xarray/tests/test_dataarray.py

@@ -7159,7 +7159,7 @@ def test_result_as_expected(self) -> None:
     def test_error_on_ellipsis_without_list(self) -> None:
         da = DataArray([[1, 2], [1, 2]], dims=("x", "y"))
         with pytest.raises(ValueError):
-            da.stack(flat=...)
+            da.stack(flat=...)  # type: ignore
 
 
 def test_nD_coord_dataarray() -> None:

xarray/tests/test_formatting.py

@@ -118,9 +118,9 @@ def test_format_items(self) -> None:
                 np.arange(4) * np.timedelta64(500, "ms"),
                 "00:00:00 00:00:00.500000 00:00:01 00:00:01.500000",
             ),
-            (pd.to_timedelta(["NaT", "0s", "1s", "NaT"]), "NaT 00:00:00 00:00:01 NaT"),
+            (pd.to_timedelta(["NaT", "0s", "1s", "NaT"]), "NaT 00:00:00 00:00:01 NaT"),  # type: ignore[arg-type, unused-ignore]
             (
-                pd.to_timedelta(["1 day 1 hour", "1 day", "0 hours"]),
+                pd.to_timedelta(["1 day 1 hour", "1 day", "0 hours"]),  # type: ignore[arg-type, unused-ignore]
                 "1 days 01:00:00 1 days 00:00:00 0 days 00:00:00",
             ),
             ([1, 2, 3], "1 2 3"),