Merge branch 'main' into theme_play

* main: (23 commits)
  Suggest type hinting (SciTools#4390)
  area weight regrid test fixes (SciTools#4432)
  Update latest.rst (SciTools#4425)
  Added @wjbenfold to the core dev list (SciTools#4423)
  Removed addition of period from wrap_lons. (SciTools#4421)
  Add release docs sections describing the role of a Release Manager (SciTools#4413)
  Subset should always return None if no value matches are found (SciTools#4417)
  What's new for SciTools#4400 (SciTools#4422)
  `iris.analysis.AreaWeighted` regrid speedup (SciTools#4400)
  [pre-commit.ci] pre-commit autoupdate (SciTools#4419)
  Remove newline to satisfy setuptools (SciTools#4418)
  Updated environment lockfiles (SciTools#4416)
  NAME loader fixes (SciTools#4411)
  Updated whatsnew for PR 4402 (SciTools#4410)
  Support test data in benchmark workflows (SciTools#4402)
  What's new for pr 4387 (SciTools#4405)
  Make concat mismatch warning for scalar coords more accurate (SciTools#4387)
  Added line to latest release notes for updates to pp_save_rules.py (SciTools#4404)
  Update pp_save_rules.py (SciTools#4391)
  [pre-commit.ci] pre-commit autoupdate (SciTools#4403)
  ...

.cirrus.yml

@@ -38,7 +38,7 @@ env:
   # Conda packages to be installed.
   CONDA_CACHE_PACKAGES: "nox pip"
   # Git commit hash for iris test data.
-  IRIS_TEST_DATA_VERSION: "2.4"
+  IRIS_TEST_DATA_VERSION: "2.5"
   # Base directory for the iris-test-data.
   IRIS_TEST_DATA_DIR: ${HOME}/iris-test-data
 

.github/workflows/benchmark.yml

@@ -10,6 +10,13 @@ jobs:
   benchmark:
     runs-on: ubuntu-latest
 
+    env:
+      IRIS_TEST_DATA_LOC_PATH: benchmarks
+      IRIS_TEST_DATA_PATH: benchmarks/iris-test-data
+      IRIS_TEST_DATA_VERSION: "2.5"
+      # Lets us manually bump the cache to rebuild
+      TEST_DATA_CACHE_BUILD: "2"
+
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
       - uses: actions/checkout@v2
@@ -38,9 +45,31 @@ jobs:
           key: ${{ runner.os }}-${{ github.sha }}
           restore-keys: ${{ runner.os }}
 
+      - name: Cache test data directory
+        id: cache-test-data
+        uses: actions/cache@v2
+        with:
+          path: |
+            ${{ env.IRIS_TEST_DATA_PATH }}
+          key:
+            test-data-${{ env.IRIS_TEST_DATA_VERSION }}-${{ env.TEST_DATA_CACHE_BUILD }}
+
+      - name: Fetch the test data
+        if: steps.cache-test-data.outputs.cache-hit != 'true'
+        run: |
+          wget --quiet https://github.com/SciTools/iris-test-data/archive/v${IRIS_TEST_DATA_VERSION}.zip -O iris-test-data.zip
+          unzip -q iris-test-data.zip
+          mkdir --parents ${GITHUB_WORKSPACE}/${IRIS_TEST_DATA_LOC_PATH}
+          mv iris-test-data-${IRIS_TEST_DATA_VERSION} ${GITHUB_WORKSPACE}/${IRIS_TEST_DATA_PATH}
+          
+      - name: Set test data var
+        run: |
+          echo "OVERRIDE_TEST_DATA_REPOSITORY=${GITHUB_WORKSPACE}/${IRIS_TEST_DATA_PATH}/test_data" >> $GITHUB_ENV
+
       - name: Run CI benchmarks
         run: |
           mkdir --parents benchmarks/.asv
+          set -o pipefail
           nox --session="benchmarks(ci compare)" | tee benchmarks/.asv/ci_compare.txt
 
       - name: Archive asv results

.pre-commit-config.yaml

@@ -6,7 +6,8 @@ files: |
         noxfile\.py|
         setup\.py|
         docs\/.+\.py|
-        lib\/.+\.py
+        lib\/.+\.py|
+        benchmarks\/.+\.py
     )
 minimum_pre_commit_version: 1.21.0
 
@@ -42,7 +43,7 @@ repos:
         args: [--config=./setup.cfg]
 
 -   repo: https://github.com/pycqa/isort
-    rev: 5.9.3
+    rev: 5.10.1
     hooks:
     -   id: isort
         types: [file, python]

benchmarks/benchmarks/metadata_manager_factory.py

@@ -9,13 +9,13 @@
 """
 
 from iris.common import (
-    metadata_manager_factory,
     AncillaryVariableMetadata,
     BaseMetadata,
     CellMeasureMetadata,
     CoordMetadata,
     CubeMetadata,
     DimCoordMetadata,
+    metadata_manager_factory,
 )
 
 

benchmarks/benchmarks/mixin.py

@@ -14,7 +14,6 @@
 from iris import coords
 from iris.common.metadata import AncillaryVariableMetadata
 
-
 LONG_NAME = "air temperature"
 STANDARD_NAME = "air_temperature"
 VAR_NAME = "air_temp"

benchmarks/benchmarks/regridding.py

@@ -0,0 +1,40 @@
+# Copyright Iris contributors
+#
+# This file is part of Iris and is released under the LGPL license.
+# See COPYING and COPYING.LESSER in the root of the repository for full
+# licensing details.
+"""
+Regridding benchmark test
+
+"""
+
+# import iris tests first so that some things can be initialised before
+# importing anything else
+from iris import tests  # isort:skip
+
+import iris
+from iris.analysis import AreaWeighted
+
+
+class HorizontalChunkedRegridding:
+    def setup(self) -> None:
+        # Prepare a cube and a template
+
+        cube_file_path = tests.get_data_path(
+            ["NetCDF", "regrid", "regrid_xyt.nc"]
+        )
+        self.cube = iris.load_cube(cube_file_path)
+
+        template_file_path = tests.get_data_path(
+            ["NetCDF", "regrid", "regrid_template_global_latlon.nc"]
+        )
+        self.template_cube = iris.load_cube(template_file_path)
+
+        # Chunked data makes the regridder run repeatedly
+        self.cube.data = self.cube.lazy_data().rechunk((1, -1, -1))
+
+    def time_regrid_area_w(self) -> None:
+        # Regrid the cube onto the template.
+        out = self.cube.regrid(self.template_cube, AreaWeighted())
+        # Realise the data
+        out.data

benchmarks/nox_asv_plugin.py

@@ -13,12 +13,12 @@
 from shutil import copy2, copytree
 from tempfile import TemporaryDirectory
 
+from asv import util as asv_util
 from asv.config import Config
 from asv.console import log
 from asv.environment import get_env_name
 from asv.plugins.conda import Conda, _find_conda
-from asv.repo import get_repo, Repo
-from asv import util as asv_util
+from asv.repo import Repo, get_repo
 
 
 class NoxConda(Conda):

docs/src/developers_guide/contributing_code_formatting.rst

@@ -57,5 +57,13 @@ will look similar to::
 .. note:: You can also run `black`_ and `flake8`_ manually.  Please see the
           their officially documentation for more information.
 
+Type Hinting
+------------
+Iris is gradually adding
+`type hints <https://docs.python.org/3/library/typing.html>`_ into the
+codebase. The reviewer will look for type hints in a pull request; if you're
+not confident with these, feel free to work together with the reviewer to
+add/improve them.
+
 
 .. _pre-commit: https://pre-commit.com/

docs/src/developers_guide/release.rst

@@ -11,6 +11,21 @@ The summary below is of the main areas that constitute the release.  The final
 section details the :ref:`iris_development_releases_steps` to take.
 
 
+.. _release_manager:
+
+Release Manager
+---------------
+A Release Manager will be nominated for each release of Iris. This role involves:
+
+* deciding which features and bug fixes should be included in the release
+* managing the project board for the release
+* using a `GitHub Releases Discussion Forum`_ for documenting intent and capturing any 
+  discussion about the release
+
+The Release Manager will make the release, ensuring that all the steps outlined
+on this page are completed.
+
+
 Before Release
 --------------
 
@@ -243,6 +258,7 @@ Post Release Steps
 
 .. _SciTools/iris: https://github.com/SciTools/iris
 .. _tag on the SciTools/Iris: https://github.com/SciTools/iris/releases
+.. _GitHub Releases Discussion Forum: https://github.com/SciTools/iris/discussions/categories/releases
 .. _conda-forge Anaconda channel: https://anaconda.org/conda-forge/iris
 .. _conda-forge iris-feedstock: https://github.com/conda-forge/iris-feedstock
 .. _CFEP-05: https://github.com/conda-forge/cfep/blob/master/cfep-05.md

docs/src/whatsnew/latest.rst

@@ -26,8 +26,9 @@ This document explains the changes made to Iris for this release
 📢 Announcements
 ================
 
-#. Welcome to `@wjbenfold`_, `@tinyendian`_ and `@larsbarring`_ who made their
-   first contributions to Iris.  The first of many we hope!
+#. Welcome to `@wjbenfold`_, `@tinyendian`_, `@larsbarring`_, `@akuhnregnier`_
+   and `@bsherratt`_ who made their first contributions to Iris.  The first of many we hope!
+#. Congratulations to `@wjbenfold`_ who has become a core developer for Iris! 🎉
 
 
 ✨ Features
@@ -81,15 +82,24 @@ This document explains the changes made to Iris for this release
    :attr:`~iris.experimental.ugrid.mesh.Connectivity.indices` under the
    `UGRID`_ model. (:pull:`4375`)
 
+#. `@bsherratt`_ added a `threshold` parameter to
+   :meth:`~iris.cube.Cube.intersection` (:pull:`4363`)
+
+#. `@wjbenfold`_ added test data to ci benchmarks so that it is accessible to
+   benchmark scripts. Also added a regridding benchmark that uses this data
+   (:pull:`4402`)
+
 
 🐛 Bugs Fixed
 =============
 
-
 #. `@rcomer`_ fixed :meth:`~iris.cube.Cube.intersection` for special cases where
    one cell's bounds align with the requested maximum and negative minimum, fixing
    :issue:`4221`. (:pull:`4278`)
 
+#. `@bsherratt`_ fixed further edge cases in
+   :meth:`~iris.cube.Cube.intersection`, including :issue:`3698` (:pull:`4363`)
+
 #. `@tinyendian`_ fixed the error message produced by :meth:`~iris.cube.CubeList.concatenate_cube`
    when a cube list contains cubes with different names, which will no longer report
    "Cube names differ: var1 != var1" if var1 appears multiple times in the list
@@ -98,6 +108,25 @@ This document explains the changes made to Iris for this release
 #. `@larsbarring`_ fixed :class:`~iris.coord_systems.GeoCS` to handle spherical ellipsoid
    parameter inverse_flattening = 0 (:issue: `4146`, :pull:`4348`)
 
+#. `@pdearnshaw`_ fixed an error in the call to :class:`cftime.datetime` in
+   :mod:`~iris.fileformats.pp_save_rules` that prevented the saving to PP of climate
+   means for DJF (:pull:`4391`)
+
+#. `@wjbenfold`_ improved the error message for failure of :meth:`~iris.cube.CubeList.concatenate`
+   to indicate that the value of a scalar coordinate may be mismatched, rather than the metadata
+   (:issue:`4096`, :pull:`4387`)
+
+#. `@bsherratt`_ fixed a regression to the NAME file loader introduced in 3.0.4,
+   as well as some long-standing bugs with vertical coordinates and number
+   formats. (:pull:`4411`)
+
+#. `@rcomer`_ fixed :meth:`~iris.cube.Cube.subset` to alway return ``None`` if
+   no value match is found.  (:pull:`4417`)
+
+#. `@wjbenfold`_ resolved an issue that previously caused regridding with lazy
+   data to take significantly longer than with real data. Relevant benchmark
+   shows a time decrease from >10s to 625ms. (:issue:`4280`, :pull:`4400`)
+
 
 💣 Incompatible Changes
 =======================
@@ -149,6 +178,12 @@ This document explains the changes made to Iris for this release
 #. `@trexfeathers`_ added more detail on making `iris-test-data`_ available
    during :ref:`developer_running_tests`. (:pull:`4359`)
 
+#. `@lbdreyer`_ added a section to the release documentation outlining the role
+   of the :ref:`release_manager`. (:pull:`4413`)
+
+#. `@trexfeathers`_ encouraged contributors to include type hinting in code
+   they are working on - :ref:`code_formatting`. (:pull:`4390`)
+
 
 💼 Internal
 ===========
@@ -183,11 +218,21 @@ This document explains the changes made to Iris for this release
 #. `@rcomer`_ modified a NetCDF saver test to prevent it triggering a numpy
    deprecation warning.  (:issue:`4374`, :pull:`4376`)
 
+#. `@akuhnregnier`_ removed addition of period from
+   :func:`~iris.analysis.cartography.wrap_lons` and updated affected tests
+   using assertArrayAllClose following :issue:`3993`.
+   (:pull:`4421`)
+
+#. `@rcomer`_ applied minor fixes to some regridding tests. (:pull:`4432`)
+
 .. comment
     Whatsnew author names (@github name) in alphabetical order. Note that,
     core dev names are automatically included by the common_links.inc:
 
+.. _@akuhnregnier: https://github.com/akuhnregnier
+.. _@bsherratt: https://github.com/bsherratt
 .. _@larsbarring: https://github.com/larsbarring
+.. _@pdearnshaw: https://github.com/pdearnshaw
 .. _@tinyendian: https://github.com/tinyendian
 
 .. comment

lib/iris/_concatenate.py

@@ -437,7 +437,7 @@ def meta_key_func(dm):
             av_and_dims = _CoordAndDims(av, tuple(dims))
             self.ancillary_variables_and_dims.append(av_and_dims)
 
-    def _coordinate_differences(self, other, attr):
+    def _coordinate_differences(self, other, attr, reason="metadata"):
         """
         Determine the names of the coordinates that differ between `self` and
         `other` for a coordinate attribute on a _CubeSignature.
@@ -451,12 +451,16 @@ def _coordinate_differences(self, other, attr):
             The _CubeSignature attribute within which differences exist
             between `self` and `other`.
 
+        * reason (string):
+            The reason to give for mismatch (function is normally, but not
+            always, testing metadata)
+
         Returns:
-            Tuple of a descriptive error message and the names of coordinates
+            Tuple of a descriptive error message and the names of attributes
             that differ between `self` and `other`.
 
         """
-        # Set up {name: coord_metadata} dictionaries.
+        # Set up {name: attribute} dictionaries.
         self_dict = {x.name(): x for x in getattr(self, attr)}
         other_dict = {x.name(): x for x in getattr(other, attr)}
         if len(self_dict) == 0:
@@ -466,7 +470,7 @@ def _coordinate_differences(self, other, attr):
         self_names = sorted(self_dict.keys())
         other_names = sorted(other_dict.keys())
 
-        # Compare coord metadata.
+        # Compare coord attributes.
         if len(self_names) != len(other_names) or self_names != other_names:
             result = ("", ", ".join(self_names), ", ".join(other_names))
         else:
@@ -476,7 +480,7 @@ def _coordinate_differences(self, other, attr):
                 if self_value != other_value:
                     diff_names.append(self_key)
             result = (
-                " metadata",
+                " " + reason,
                 ", ".join(diff_names),
                 ", ".join(diff_names),
             )
@@ -542,7 +546,9 @@ def match(self, other, error_on_mismatch):
             )
         # Check scalar coordinates.
         if self.scalar_coords != other.scalar_coords:
-            differences = self._coordinate_differences(other, "scalar_coords")
+            differences = self._coordinate_differences(
+                other, "scalar_coords", reason="values or metadata"
+            )
             msgs.append(
                 msg_template.format("Scalar coordinates", *differences)
             )

lib/iris/analysis/_area_weighted.py

@@ -71,6 +71,7 @@ def __init__(self, src_grid_cube, target_grid_cube, mdtol=1):
             self.meshgrid_x,
             self.meshgrid_y,
             self.weights_info,
+            self.index_info,
         ) = _regrid_info
 
     def __call__(self, cube):
@@ -124,6 +125,7 @@ def __call__(self, cube):
             self.meshgrid_x,
             self.meshgrid_y,
             self.weights_info,
+            self.index_info,
         )
         return _regrid_area_weighted_rectilinear_src_and_grid__perform(
             cube, _regrid_info, mdtol=self._mdtol

lib/iris/analysis/cartography.py

@@ -70,7 +70,7 @@ def wrap_lons(lons, base, period):
     # It is important to use 64bit floating precision when changing a floats
     # numbers range.
     lons = lons.astype(np.float64)
-    return ((lons - base + period * 2) % period) + base
+    return ((lons - base) % period) + base
 
 
 def unrotate_pole(rotated_lons, rotated_lats, pole_lon, pole_lat):