Synchronize mypy test requirements to 1.17.1 (#10751)

* Update mypy test requirement to 1.17.1

* Fix mypy 1.17.1 compatibility issues

- Add list-item to type ignore for df.columns assignment
- Remove unnecessary attr-defined type ignores that mypy 1.17.1 now understands

* Restore type ignores needed by mypy 1.17.1 in CI environment

---------

Co-authored-by: Maximilian Roos <[email protected]>
Co-authored-by: Maximilian Roos <[email protected]>

Author: shoyer

.github/workflows/ci-additional.yaml

@@ -116,7 +116,7 @@ jobs:
           python xarray/util/print_versions.py
       - name: Install mypy
         run: |
-          python -m pip install "mypy==1.15" --force-reinstall
+          python -m pip install "mypy==1.17.1" --force-reinstall
 
       - name: Run mypy
         run: |
@@ -167,7 +167,7 @@ jobs:
           python xarray/util/print_versions.py
       - name: Install mypy
         run: |
-          python -m pip install "mypy==1.15" --force-reinstall
+          python -m pip install "mypy==1.17.1" --force-reinstall
 
       - name: Run mypy
         run: |

xarray/tests/test_dataset.py

@@ -5303,7 +5303,7 @@ def test_from_dataframe_unsorted_levels(self) -> None:
     def test_from_dataframe_non_unique_columns(self) -> None:
         # regression test for GH449
         df = pd.DataFrame(np.zeros((2, 2)))
-        df.columns = ["foo", "foo"]  # type: ignore[assignment,unused-ignore]
+        df.columns = ["foo", "foo"]  # type: ignore[assignment,list-item,unused-ignore]
         with pytest.raises(ValueError, match=r"non-unique columns"):
             Dataset.from_dataframe(df)