ci(typeannotation): GitHub action to check files changed in a PR

.github/workflows/mypy-pr.yml

@@ -0,0 +1,41 @@
+name: Type annotation (PR)
+
+on:
+  pull_request:
+    paths:
+      - 'datasalad/**.py'
+      - '!**/tests/**.py'
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Setup Python
+        uses: actions/setup-python@v5
+        with:
+          # run on a "fresh" python, but see mypy flag to check for the oldest supported version
+          python-version: 3.12
+          architecture: x64
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Install mypy
+        run: python -m pip install mypy  # you can pin your preferred version
+      - name: Get Python changed files
+        id: changed-py-files
+        uses: tj-actions/changed-files@v44
+        with:
+          files: |
+            *.py
+            **/*.py
+      - name: Type check changed files
+        if: steps.changed-py-files.outputs.any_changed == 'true'
+        run: |
+          # get any type stubs that mypy thinks it needs
+          mypy --install-types --non-interactive --follow-imports skip ${{ steps.changed-py-files.outputs.all_changed_files }}
+          # run mypy on the modified files only, and do not even follow imports.
+          # this results is a fairly superficial test, but given the overall
+          # state of annotations, we strive to become more correct incrementally
+          # with focused error reports, rather than barfing a huge complaint
+          # that is unrelated to the changeset someone has been working on.
+          # run on the oldest supported Python version
+          mypy --python-version 3.8 --follow-imports skip --pretty --show-error-context ${{ steps.changed-py-files.outputs.all_changed_files }}

.github/workflows/mypy-project.yml

@@ -0,0 +1,29 @@
+name: Type annotation (project)
+
+on:
+  push:
+    paths:
+      - 'datasalad/**.py'
+      - '!**/tests/**.py'
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Setup Python
+        uses: actions/setup-python@v5
+        with:
+          # run on a "fresh" python, but see mypy flag to check for the oldest supported version
+          python-version: 3.12
+          architecture: x64
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Install mypy
+        run: python -m pip install mypy  # you can pin your preferred version
+      - name: Type check changed files
+        run: |
+          # get any type stubs that mypy thinks it needs
+          mypy --install-types --non-interactive --follow-imports skip datasalad
+          # run mypy on the full project.
+          # run on the oldest supported Python version
+          mypy --python-version 3.8 --pretty --show-error-context datasalad

datasalad/dummy.py

@@ -1,2 +1,2 @@
-def not_covered():
+def not_covered() -> None:
     pass

pyproject.toml

@@ -113,10 +113,10 @@ schema_pattern = "(?s)(ci|doc|feat|fix|perf|rf|style|test|chore|revert|bump)(\\(
 "^fix" = "PATCH"
 
 [tool.commitizen.customize.change_type_map]
-"BREAKING CHANGE" = "🪓 Breaking changes"
-doc = "📝 Documentation"
-feat = "💫 New features"
-fix = "🐛 Bug Fixes"
-test = "🛡 Tests"
-rf = "🏠 Refactorings"
-perf = "🚀 Performance improvements"
+"BREAKING CHANGE" = "Breaking changes"
+doc = "Documentation"
+feat = "New features"
+fix = "Bug Fixes"
+test = "Tests"
+rf = "Refactorings"
+perf = "Performance improvements"