Fix pre-commit workflow on forks

Author: C-Achard

.github/workflows/format.yml

@@ -4,23 +4,34 @@ on:
   pull_request:
     types: [opened, synchronize, reopened]
 
+permissions:
+  contents: read
+
 jobs:
   detect_changes:
     runs-on: ubuntu-latest
     outputs:
       changed: ${{ steps.changed_files.outputs.changed }}
 
     steps:
-      - name: Checkout full history
+      - name: Checkout PR
         uses: actions/checkout@v6
         with:
           fetch-depth: 0
+          persist-credentials: false
 
       - name: Detect changed files
         id: changed_files
         run: |
-          git fetch origin ${{ github.base_ref }}
-          CHANGED_FILES=$(git diff --name-only origin/${{ github.base_ref }}...HEAD)
+          # git fetch origin ${{ github.base_ref }}
+          # CHANGED_FILES=$(git diff --name-only origin/${{ github.base_ref }}...HEAD)
+          BASE_SHA="${{ github.event.pull_request.base.sha }}"
+          HEAD_SHA="${{ github.event.pull_request.head.sha }}"
+
+          echo "Base SHA: $BASE_SHA"
+          echo "Head SHA: $HEAD_SHA"
+
+          CHANGED_FILES=$(git diff --name-only "$BASE_SHA" "$HEAD_SHA")
 
           {
             echo "changed<<EOF"
@@ -39,11 +50,12 @@ jobs:
     if: ${{ needs.detect_changes.outputs.changed != '' }}
 
     steps:
-      - name: Checkout PR branch
+      - name: Checkout PR head commit
         uses: actions/checkout@v6
         with:
           fetch-depth: 0
-          ref: ${{ github.head_ref }}
+          ref: ${{ github.event.pull_request.head.sha }}
+          persist-credentials: false
 
       - name: Set up Python
         uses: actions/setup-python@v6