ruff compliance for TC

changelog/7203.internal.rst

@@ -0,0 +1 @@
+:user:`bouweandela` enabled [Ruff type checking (TC) rules](https://docs.astral.sh/ruff/rules/#flake8-type-checking-tc).

lib/iris/_lazy_data.py

@@ -9,8 +9,7 @@
 """
 
 from functools import lru_cache, partial, wraps
-from types import ModuleType
-from typing import Sequence
+from typing import TYPE_CHECKING, Sequence
 
 import dask
 import dask.array as da
@@ -21,6 +20,9 @@
 
 import iris.exceptions
 
+if TYPE_CHECKING:
+    from types import ModuleType
+
 MAX_CACHE_SIZE = 100
 """Maximum number of Dask arrays to cache."""
 

lib/iris/analysis/__init__.py

@@ -45,8 +45,7 @@
 from functools import wraps
 from inspect import getfullargspec
 import itertools
-from numbers import Number
-from typing import Optional, Protocol, Union
+from typing import TYPE_CHECKING, Optional, Protocol, Union
 import warnings
 
 from cf_units import Unit
@@ -65,6 +64,9 @@
 from iris.exceptions import LazyAggregatorError
 import iris.util
 
+if TYPE_CHECKING:
+    from numbers import Number
+
 __all__ = (
     "Aggregator",
     "AreaWeighted",

lib/iris/common/metadata.py

@@ -20,12 +20,13 @@
 import re
 from typing import TYPE_CHECKING, Any
 
-import cf_units
 import numpy as np
 import numpy.ma as ma
 from xxhash import xxh64_hexdigest
 
 if TYPE_CHECKING:
+    import cf_units
+
     from iris.common.mixin import CFVariableMixin
     from iris.coords import CellMethod
     from iris.util import Axis

lib/iris/cube.py

@@ -31,7 +31,6 @@
 from xml.dom.minidom import Document
 
 from cf_units import Unit
-import dask.array as da
 import numpy as np
 import numpy.ma as ma
 from packaging.version import Version
@@ -45,7 +44,6 @@
 from iris.analysis.cartography import wrap_lons
 import iris.analysis.maths
 import iris.aux_factory
-from iris.aux_factory import AuxCoordFactory
 from iris.common import CFVariableMixin, CubeMetadata, metadata_manager_factory
 from iris.common.metadata import BaseMetadata, CoordMetadata, metadata_filter
 from iris.common.mixin import LimitedAttributeDict
@@ -61,10 +59,10 @@
 )
 
 if TYPE_CHECKING:
-    from typing import TYPE_CHECKING
-
+    import dask.array as da
     from numpy.typing import ArrayLike
 
+    from iris.aux_factory import AuxCoordFactory
     import iris.mesh
     from iris.mesh import MeshCoord
 import iris.exceptions

lib/iris/fileformats/netcdf/saver.py

@@ -66,7 +66,12 @@
 
 if TYPE_CHECKING:
     from iris.cube import Cube
-    from iris.mesh.components import MeshXY
+    from iris.mesh.components import (
+        MeshEdgeCoords,
+        MeshFaceCoords,
+        MeshNodeCoords,
+        MeshXY,
+    )
 # Get the logger : shared logger for all in 'iris.fileformats.netcdf'.
 from . import logger
 
@@ -990,13 +995,6 @@ def _add_aux_coords(
             NetCDF data compression keyword arguments.
 
         """
-        from iris.mesh.components import (
-            MeshEdgeCoords,
-            MeshFaceCoords,
-            MeshNodeCoords,
-            MeshXY,
-        )
-
         # Exclude any mesh coords, which are bundled in with the aux-coords.
         coords_to_add = [
             coord for coord in cube.aux_coords if not hasattr(coord, "mesh")

lib/iris/mesh/utils.py

@@ -12,14 +12,16 @@
 """
 
 from collections.abc import Sequence
-from typing import Union
+from typing import TYPE_CHECKING, Union
 
 import dask.array as da
 import numpy as np
 
-from iris.common.metadata import CoordMetadata
 from iris.cube import Cube
 
+if TYPE_CHECKING:
+    from iris.common.metadata import CoordMetadata
+
 
 def recombine_submeshes(
     mesh_cube: Cube,

lib/iris/tests/stock/__init__.py

@@ -8,9 +8,8 @@
 
 from datetime import datetime
 from pathlib import Path
-from typing import NamedTuple
+from typing import TYPE_CHECKING, NamedTuple
 
-from cartopy.crs import CRS
 from cf_units import Unit
 import numpy as np
 import numpy.ma as ma
@@ -30,6 +29,9 @@
     sample_2d_latlons,
 )
 
+if TYPE_CHECKING:
+    from cartopy.crs import CRS
+
 
 def lat_lon_cube():
     """Returns a cube with a latitude and longitude suitable for testing

pyproject.toml

@@ -329,10 +329,6 @@ ignore = [
     # https://docs.astral.sh/ruff/rules/#flake8-tidy-imports-tid
     "TID",
 
-    # flake8-type-checking (TCH)
-    # https://docs.astral.sh/ruff/rules/#flake8-type-checking-tch
-    "TCH",
-
     # flake8-unused-arguments (ARG)
     # https://docs.astral.sh/ruff/rules/#flake8-unused-arguments-arg
     "ARG",