Add generate-aggregations Pixi task and CI workflow

.github/workflows/ci.yaml

@@ -189,6 +189,49 @@ jobs:
           name: codecov-umbrella
           fail_ci_if_error: false
 
+  check-generate-aggregations:
+    name: "Check generate-aggregations is up-to-date"
+    runs-on: ubuntu-latest
+    needs: cache-pixi-lock
+    if: |
+      github.event_name == 'pull_request'
+      && needs.cache-pixi-lock.result == 'success'
+    defaults:
+      run:
+        shell: bash -l {0}
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          fetch-depth: 0
+          persist-credentials: false
+
+      - name: Check if generate_aggregations.py changed
+        id: filter
+        run: |
+          if git diff --name-only origin/${GITHUB_BASE_REF}...HEAD | grep -q 'xarray/util/generate_aggregations.py'; then
+            echo "changed=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "changed=false" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: Restore cached pixi lockfile
+        if: steps.filter.outputs.changed == 'true'
+        uses: Parcels-code/pixi-lock/restore@38495788b79a5ff26009aecc15daa9a8310b8832 # v0.1.0
+        with:
+          cache-key: ${{ needs.cache-pixi-lock.outputs.cache-key }}
+
+      - uses: prefix-dev/setup-pixi@a09b6247153796b190642a2b53fac4241043cf6f # v0.10.0
+        if: steps.filter.outputs.changed == 'true'
+        with:
+          pixi-version: ${{ needs.cache-pixi-lock.outputs.pixi-version }}
+          cache: true
+          cache-write: false
+
+      - name: Run generate-aggregations-ci
+        if: steps.filter.outputs.changed == 'true'
+        run: |
+          pixi run generate-aggregations-ci
+
   event_file:
     name: "Event File"
     runs-on: ubuntu-slim

pixi.toml

@@ -211,9 +211,25 @@ pytz = "*"
 hypothesis = "*"
 coveralls = "*"
 
+[feature.test.pypi-dependencies]
+pytest-accept = ">=0.2.2, <0.3" # needed for task generate-aggregations
+
 [feature.test.tasks]
 test = { cmd = "pytest", description = "Run the test suite with pytest." }
 
+# The second run of pytest is deliberate, since the first will return an error while replacing the doctests
+generate-aggregations = { cmd = """python xarray/util/generate_aggregations.py &&\
+! pytest --doctest-modules xarray/core/_aggregations.py --accept &&\
+pytest --doctest-modules xarray/core/_aggregations.py &&\
+! pytest --doctest-modules xarray/namedarray/_aggregations.py --accept  &&\
+pytest --doctest-modules xarray/namedarray/_aggregations.py &&\
+echo 'Aggregations generated successfully!'
+""", description = "Generate module and stub file for arithmetic operators of various xarray classes." }
+generate-aggregations-ci = { cmd = 'test -z "$(git status --porcelain)" && echo "Success! Generate-aggregations matches the committed tree" || echo "Failure :( . Generate-aggregations does not match the committed files"', depends-on = [
+  'generate-aggregations',
+  'pre-commit',
+] }
+
 [feature.doc.dependencies]
 kerchunk = "*"
 ipykernel = "*"
@@ -305,7 +321,7 @@ mypy = { cmd = "mypy --install-types --non-interactive --cobertura-xml-report my
 pre-commit = "*"
 
 [feature.pre-commit.tasks]
-pre-commit = { cmd = "pre-commit", description = "Run pre-commit hooks and linters." }
+pre-commit = { cmd = "pre-commit run --all-files || true", description = "Run pre-commit hooks and linters." } # `|| true` so that this can be used as a task dependency
 
 [feature.release.dependencies]
 gitpython = "*"
@@ -318,9 +334,6 @@ release-contributors = { cmd = "python ci/release_contributors.py", description
 ipython = ">=9.8.0,<10"
 black = ">=25.1.0,<26"
 
-[feature.dev.pypi-dependencies]
-pytest-accept = ">=0.2.2, <0.3"
-
 [feature.policy.pypi-dependencies]
 xarray-minimum-dependency-policy = "*"
 

xarray/util/generate_aggregations.py

@@ -3,16 +3,7 @@
 For internal xarray development use only.
 
 Usage:
-    python xarray/util/generate_aggregations.py
-    pytest --doctest-modules xarray/core/_aggregations.py --accept
-    pytest --doctest-modules xarray/core/_aggregations.py
-    pytest --doctest-modules xarray/namedarray/_aggregations.py --accept
-    pytest --doctest-modules xarray/namedarray/_aggregations.py
-
-This requires [pytest-accept](https://github.com/max-sixty/pytest-accept).
-The second run of pytest is deliberate, since the first will return an error
-while replacing the doctests.
-
+    pixi run generate-aggregations
 """
 
 import textwrap