Run pre-commit on changed files in CI

Author: eggpig

.github/workflows/pre-commit.yaml

@@ -1,17 +1,38 @@
 name: pre-commit
 
 on:
+  workflow_dispatch:
   pull_request:
+    branches:
+      - pybind11
   push:
+    branches:
+      - pybind11
 
 jobs:
   pre-commit:
     runs-on: ubuntu-22.04
     steps:
-    - uses: actions/checkout@v3
-    - uses: actions/setup-python@v4
+    - uses: actions/checkout@v4
       with:
-        python-version: '3.10'
-    - uses: pre-commit/action@v3.0.0
+        fetch-depth: 0
+
+    - uses: actions/setup-python@v5
       with:
-        extra_args: "--all-files"
+        python-version: '3.10'
+
+    - name: Install pre-commit
+      run: python -m pip install pre-commit
+
+    - name: Run pre-commit on changed files
+      shell: bash
+      run: |
+        if [[ "${{ github.event_name }}" == "pull_request" ]]; then
+          base_ref="${{ github.event.pull_request.base.sha }}"
+        elif [[ -n "${{ github.event.before }}" && ! "${{ github.event.before }}" =~ ^0+$ ]]; then
+          base_ref="${{ github.event.before }}"
+        else
+          base_ref="$(git rev-parse HEAD~1)"
+        fi
+
+        pre-commit run --show-diff-on-failure --color=always --from-ref "$base_ref" --to-ref "${{ github.sha }}"