ci: Add format check workflow

.github/workflows/format.yml

@@ -0,0 +1,66 @@
+name: Format check
+
+on:
+  pull_request:
+    branches:
+      - main
+    paths:
+      - '**.py'
+
+jobs:
+  find-changed-files:
+    runs-on: ubuntu-latest
+    outputs:
+      files: ${{ steps.git-diff-files.outputs.files }}
+    name: Detect added and changed files
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Create json diff
+        uses: GrantBirki/git-diff-action@v2
+        id: git-diff
+        with:
+          base_branch: origin/main
+          search_path: '**.py'
+          json_diff_file_output: diff.json
+          file_output_only: 'true'
+          # Ignore deleted files
+          git_options: '--no-color --diff-filter=d'
+
+      - name: Convert json diff to matrix array
+        id: git-diff-files
+        env:
+          JSON_DIFF: ${{ steps.git-diff.outputs.json-diff-path }}
+        run: |
+          # Github output expects oneliners, use compact mode
+          files=$(cat $JSON_DIFF | jq -c -r '[.files[] | {path: .path}]')
+          echo "files=$files" >> $GITHUB_OUTPUT
+
+  ruff-format:
+    needs: find-changed-files
+    if: ${{ needs.find-changed-files.outputs.files != '[]' }}
+    runs-on: ubuntu-latest
+    # Allow the workflow run to pass when this job fails
+    continue-on-error: true
+    strategy:
+      fail-fast: false
+      matrix:
+        files: ${{ fromJSON(needs.find-changed-files.outputs.files) }}
+
+    name: Check file ${{ matrix.files.path }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Run ruff format check for ${{ matrix.files.path }}
+        uses: astral-sh/ruff-action@v1
+        with:
+          args: "format --check --diff"
+          src: "${{ matrix.files.path }}"
+
+      - name: Annotate unformatted file
+        if: ${{ failure() }}
+        run: |
+          echo "::warning file=${{ matrix.files.path }},title=File format check failed::Run 'ruff format ${{ matrix.files.path }}'"

pyproject.toml

@@ -60,3 +60,7 @@ extend-select = [
 ignore = [
   "UP027", # deprecated pyupgrade rule
 ]
+
+[tool.ruff.format]
+quote-style = "preserve"
+line-ending = "lf"

tests/test_alias.py

@@ -10,13 +10,15 @@
 
 assert 'TOXTEMPDIR' in os.environ, "you must run these tests using tox"
 
+
 @pytest.fixture(autouse=True)
 def autouse_tmpdir(config_tmpdir, west_init_tmpdir):
     # Since this module tests west's configuration file features,
     # adding autouse=True to the config_tmpdir and west_init_tmpdir fixtures
     # saves typing and is less error-prone than using it below in every test case.
     pass
 
+
 def test_alias_commands():
     cmd('config alias.test1 topdir')
     cmd('config --global alias.test2 topdir')
@@ -28,6 +30,7 @@ def test_alias_commands():
     assert cmd('test2') == topdir_out
     assert cmd('test3') == topdir_out
 
+
 def test_alias_help():
     cmd('config alias.test topdir')
 
@@ -36,13 +39,15 @@ def test_alias_help():
     assert "An alias that expands to: topdir" in help_out
     assert cmd('-h test') == help_out
 
+
 def test_alias_recursive_commands():
     list_format = '{revision} TESTALIAS {name}'
     cmd(['config', 'alias.test1', f'list -f "{list_format}"'])
     cmd('config alias.test2 test1')
 
     assert cmd('test2') == cmd(['list', '-f', list_format])
 
+
 def test_alias_infinite_recursion():
     cmd('config alias.test1 test2')
     cmd('config alias.test2 test3')
@@ -53,6 +58,7 @@ def test_alias_infinite_recursion():
 
     assert 'unknown command "test1";' in str(excinfo.value.stdout)
 
+
 def test_alias_empty():
     cmd(['config', 'alias.empty', ''])
 
@@ -64,18 +70,21 @@ def test_alias_empty():
 
     assert 'empty alias "empty"' in str(excinfo.value.stdout)
 
+
 def test_alias_early_args():
     cmd('config alias.test1 topdir')
 
     # An alias with an early command argument shouldn't fail
     assert "Replacing alias test1 with ['topdir']" in cmd('-v test1')
 
+
 def test_alias_command_with_arguments():
     list_format = '{revision} TESTALIAS {name}'
     cmd(['config', 'alias.revs', f'list -f "{list_format}"'])
 
     assert cmd('revs') == cmd(['list', '-f', list_format])
 
+
 def test_alias_override():
     before = cmd('list')
     list_format = '{name} : {revision}'

tests/test_commands.py

@@ -8,6 +8,7 @@
 
 gv = WestCommand._parse_git_version
 
+
 def test_parse_git_version():
     # White box test for git parsing behavior.
     assert gv(b'git version 2.25.1\n') == (2, 25, 1)