CI: run mypy in full env

.github/workflows/ci-additional.yaml

@@ -157,6 +157,50 @@ jobs:
         run: |
           python -m pytest --doctest-modules xarray --ignore xarray/tests
 
+  typing:
+    name: Type checking (mypy)
+    runs-on: "ubuntu-latest"
+    needs: detect-ci-trigger
+    if: false && needs.detect-ci-trigger.outputs.triggered == 'false'
+    defaults:
+      run:
+        shell: bash -l {0}
+
+    steps:
+      - name: Cancel previous runs
+        uses: styfle/[email protected]
+        with:
+          access_token: ${{ github.token }}
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0 # Fetch all history for all branches and tags.
+      - uses: conda-incubator/setup-miniconda@v2
+        with:
+          channels: conda-forge
+          channel-priority: strict
+          mamba-version: "*"
+          activate-environment: xarray-tests
+          auto-update-conda: false
+          python-version: "3.8"
+
+      - name: Install conda dependencies
+        run: |
+          mamba env update -f ci/requirements/environment.yml
+      - name: Install mypy
+        run: |
+          mamba install --file ci/requirements/mypy_only
+      - name: Install xarray
+        run: |
+          python -m pip install --no-deps -e .
+      - name: Version info
+        run: |
+          conda info -a
+          conda list
+          python xarray/util/print_versions.py
+      - name: Run mypy
+        run: |
+          python -m mypy xarray
+
   min-version-policy:
     name: Minimum Version Policy
     runs-on: "ubuntu-latest"

.pre-commit-config.yaml

@@ -30,6 +30,7 @@ repos:
   #     - id: velin
   #       args: ["--write", "--compact"]
   - repo: https://github.com/pre-commit/mirrors-mypy
+    # version must correspond to the one in .github/workflows/ci-additional.yaml
     rev: v0.812
     hooks:
       - id: mypy

ci/requirements/mypy_only

@@ -0,0 +1,3 @@
+# used for the "Type checking (mypy)" CI run
+# version must correspond to the one in .pre-commit-config.yaml
+mypy=0.812