Add ruff linting and formatting CI

.github/workflows/ruff.yml

@@ -0,0 +1,69 @@
+name: code analysis
+
+on: pull_request
+
+permissions:
+  contents: read
+
+jobs:
+  ruff:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Get the list of changed files
+      id: diff
+      run: |
+        git fetch --depth=1 origin $GITHUB_BASE_REF 
+        git diff --name-only origin/$GITHUB_BASE_REF > changed_files.txt
+
+    - name: Install ruff
+      uses: astral-sh/ruff-action@v3
+      with:
+        args: "--version"
+
+    - name: Lint code
+      run: |
+        files=$(cat changed_files.txt | grep '\.py$' || echo "")
+        if [ -n "$files" ]; then
+          echo "$files" | xargs ruff check --diff || true
+          echo "$files" | xargs ruff check
+        else
+          echo "No python files to lint"
+        fi
+
+    - name: Format code
+      if: always()
+      run: |
+        files=$(cat changed_files.txt | grep '\.py$' || echo "")
+        if [ -n "$files" ]; then
+          diff_command=""
+          apply_command=""
+          for file in $files; do
+            while IFS=- read -r start length; do
+              [ -z "$start" ] && continue
+              length=${length:-1}
+              # Skip invalid ranges
+              if [ "$start" -eq 0 ] || [ "$length" -eq 0 ]; then
+                continue
+              fi
+              end=$((start + length))
+              diff_command+="ruff format --diff --range $start-$end $file && "
+              apply_command+="ruff format --range $start-$end $file && "
+            done < <(git diff --unified=0 origin/$GITHUB_BASE_REF "$file" | grep '^@@' | sed -E 's/^@@ -[0-9]+(,[0-9]+)? \+([0-9]+)(,([0-9]+))? @@.*/\2-\4/')
+          done
+
+          if [ -n "$diff_command" ]; then
+            diff_command=${diff_command% && }
+            if ! eval "$diff_command"; then
+              apply_command=${apply_command% && }
+              echo -e "::error::Formatting failed. To apply the changes locally, run the following command:\n$apply_command"
+              exit 123
+            fi
+          else
+            echo "No ranges detected to format."
+          fi
+        else
+          echo "No python files to format"
+        fi