Port dependency fixes to v3.3.x.

docs/src/whatsnew/3.3.rst

@@ -52,6 +52,14 @@ v3.3.1 |build_date| [unreleased]
     #. `@pp-mo`_ ensured that :data:`iris.cube.Cube.cell_methods` must always be an iterable
        of :class:`iris.coords.CellMethod` objects (:pull:`4933`).
 
+    #. `@trexfeathers`_ advanced the Cartopy pin to ``>=0.21``, as Cartopy's
+       change to default Transverse Mercator projection affects an Iris test.
+       See `SciTools/cartopy@fcb784d`_ and `SciTools/cartopy@8860a81`_ for more
+       details. (:pull:`4968`)
+
+    #. `@trexfeathers`_ introduced the ``netcdf4!=1.6.1`` pin to avoid a
+       problem with segfaults. (:pull:`4968`)
+
 
 📢 Announcements
 ================
@@ -361,3 +369,5 @@ v3.3.1 |build_date| [unreleased]
 .. _PyData Sphinx Theme: https://pydata-sphinx-theme.readthedocs.io/en/stable/index.html
 .. _pytest: https://docs.pytest.org
 .. _setuptools-scm: https://github.com/pypa/setuptools_scm
+.. _SciTools/cartopy@fcb784d: https://github.com/SciTools/cartopy/commit/fcb784daa65d95ed9a74b02ca292801c02bc4108
+.. _SciTools/cartopy@8860a81: https://github.com/SciTools/cartopy/commit/8860a8186d4dc62478e74c83f3b2b3e8f791372e

lib/iris/analysis/cartography.py

@@ -1008,8 +1008,8 @@ def _transform_distance_vectors_tolerance_mask(
     u_one_t, v_zero_t = _transform_distance_vectors(ones, zeros, ds, dx2, dy2)
     u_zero_t, v_one_t = _transform_distance_vectors(zeros, ones, ds, dx2, dy2)
     # Squared magnitudes should be equal to one within acceptable tolerance.
-    # A value of atol=2e-3 is used, which corresponds to a change in magnitude
-    # of approximately 0.1%.
+    # A value of atol=2e-3 is used, which masks any magnitude changes >0.5%
+    #  (approx percentage - based on experimenting).
     sqmag_1_0 = u_one_t**2 + v_zero_t**2
     sqmag_0_1 = u_zero_t**2 + v_one_t**2
     mask = np.logical_not(

lib/iris/tests/unit/analysis/cartography/test_rotate_winds.py

@@ -16,6 +16,7 @@
 import cartopy.crs as ccrs
 import numpy as np
 import numpy.ma as ma
+import pytest
 
 from iris.analysis.cartography import rotate_winds, unrotate_pole
 import iris.coord_systems
@@ -410,7 +411,11 @@ def test_transposed(self):
 class TestMasking(tests.IrisTest):
     def test_rotated_to_osgb(self):
         # Rotated Pole data with large extent.
-        x = np.linspace(311.9, 391.1, 10)
+        # A 'correct' answer is not known for this test; it is therefore
+        #  written as a 'benchmark' style test - a change in behaviour will
+        #  cause a test failure, requiring developers to approve/reject the
+        #  new behaviour.
+        x = np.linspace(221.9, 301.1, 10)
         y = np.linspace(-23.6, 24.8, 8)
         u, v = uv_cubes(x, y)
         ut, vt = rotate_winds(u, v, iris.coord_systems.OSGB())
@@ -422,14 +427,14 @@ def test_rotated_to_osgb(self):
         # Snapshot of mask with fixed tolerance of atol=2e-3
         expected_mask = np.array(
             [
-                [1, 1, 1, 0, 0, 0, 0, 0, 0, 1],
-                [1, 1, 1, 0, 0, 0, 0, 0, 0, 1],
-                [1, 1, 1, 1, 0, 0, 0, 0, 1, 1],
-                [1, 1, 1, 1, 0, 0, 0, 0, 1, 1],
-                [1, 1, 1, 1, 0, 0, 0, 0, 1, 1],
-                [1, 1, 1, 1, 1, 0, 0, 1, 1, 1],
-                [1, 1, 1, 1, 1, 0, 0, 1, 1, 1],
-                [1, 1, 1, 1, 1, 0, 0, 1, 1, 1],
+                [0, 0, 0, 1, 1, 1, 0, 0, 0, 1],
+                [0, 0, 0, 0, 1, 1, 1, 0, 1, 1],
+                [0, 0, 0, 0, 0, 1, 1, 1, 1, 1],
+                [0, 0, 0, 0, 1, 1, 1, 0, 0, 0],
+                [0, 0, 0, 1, 1, 1, 1, 1, 0, 0],
+                [0, 1, 1, 1, 1, 1, 1, 0, 0, 0],
+                [0, 1, 1, 1, 0, 1, 1, 1, 0, 0],
+                [0, 1, 0, 0, 0, 0, 1, 1, 1, 0],
             ],
             np.bool_,
         )
@@ -443,7 +448,7 @@ def test_rotated_to_osgb(self):
         # Calculate percentage error (note there are no zero magnitudes
         # so we can divide safely).
         anom = 100.0 * np.abs(res_mag - expected_mag) / expected_mag
-        self.assertTrue(anom[~ut.data.mask].max() < 0.1)
+        assert anom[~ut.data.mask].max() == pytest.approx(0.3227935)
 
     def test_rotated_to_unrotated(self):
         # Suffiently accurate so that no mask is introduced.

requirements/ci/py310.yml

@@ -11,12 +11,12 @@ dependencies:
   - setuptools-scm >=7
 
 # Core dependencies.
-  - cartopy >=0.20
+  - cartopy >=0.21
   - cf-units >=3.1
   - cftime >=1.5
   - dask-core >=2
   - matplotlib
-  - netcdf4
+  - netcdf4 !=1.6.1
   - numpy >=1.19
   - python-xxhash
   - pyproj

requirements/ci/py38.yml

@@ -11,12 +11,12 @@ dependencies:
   - setuptools-scm >=7
 
 # Core dependencies.
-  - cartopy >=0.20
+  - cartopy >=0.21
   - cf-units >=3.1
   - cftime >=1.5
   - dask-core >=2
   - matplotlib
-  - netcdf4
+  - netcdf4 !=1.6.1
   - numpy >=1.19
   - python-xxhash
   - pyproj

requirements/ci/py39.yml

@@ -11,12 +11,12 @@ dependencies:
   - setuptools-scm >=7
 
 # Core dependencies.
-  - cartopy >=0.20
+  - cartopy >=0.21
   - cf-units >=3.1
   - cftime >=1.5
   - dask-core >=2
   - matplotlib
-  - netcdf4
+  - netcdf4 !=1.6.1
   - numpy >=1.19
   - python-xxhash
   - pyproj

setup.cfg

@@ -45,12 +45,12 @@ version = attr: iris.__version__
 [options]
 include_package_data = True
 install_requires =
-    cartopy>=0.20
+    cartopy>=0.21
     cf-units>=3.1
     cftime>=1.5.0
     dask[array]>=2
     matplotlib
-    netcdf4
+    netcdf4!=1.6.1
     numpy>=1.19
     scipy
     shapely!=1.8.3