Suggest clang-format changes on PRs (#499)

* Apply clang-format locally and suggest changes

* Add executable permission to clang format apply

.github/workflows/clang-format-check.yml

@@ -1,6 +1,6 @@
 name: Check Clang-Format on Diff
 
-on: [push, pull_request]
+on: [pull_request]
 
 jobs:
   clang-format:
@@ -23,6 +23,49 @@ jobs:
       run: |
         sudo apt-get install clang-format-17
 
-    - name: Check Clang-Format on Diff
+    - name: Fetch branches to check
       run: |
-        ./clang-format-diff.sh ${{ github.base_ref }} ${{ github.ref }}
+        git fetch origin ${{ github.base_ref }}
+        if [ "${{ github.repository_owner }}" != "${{ github.event.pull_request.head.repo.owner.login }}" ]; then
+          fork_owner="${{ github.event.pull_request.head.repo.owner.login }}"
+          fork_url=$(git remote get-url origin)
+          git remote add fork "$fork_url"
+          git fetch fork ${{ github.head_ref }}
+        else
+          git fetch origin ${{ github.head_ref }}
+        fi
+
+    - name: Apply clang-format locally
+      if: github.event_name == 'pull_request'
+      run: |
+        if [ "${{ github.repository_owner }}" != "${{ github.event.pull_request.head.repo.owner.login }}" ]; then
+          ./scripts/clang-format/clang-format-apply.sh origin/${{ github.base_ref }} fork/${{ github.head_ref }}
+        else
+          ./scripts/clang-format/clang-format-apply.sh origin/${{ github.base_ref }} origin/${{ github.head_ref }}
+        fi
+
+    - name: Save clang-format changes as patch
+      run: |
+        git diff -U0
+        git diff -U0 > clang_format.patch
+
+    - name: Check if patch is not empty
+      run: |
+        if [ -s clang_format.patch ]; then
+          echo "Patch is not empty"
+          echo "patch_not_empty=true" >> $GITHUB_STATE
+        else
+          echo "Patch is empty"
+          echo "patch_not_empty=false" >> $GITHUB_STATE
+        fi
+
+    - name: Post patch as comment
+      if: env.GITHUB_STATE.patch_not_empty == 'true'
+      run: |
+        API_URL="https://api.github.com/repos/${{ github.repository }}/issues/${{ github.event.pull_request.number }}/comments"
+        curl -X POST \
+          -H "Accept: application/vnd.github+json" \
+          -H "Authorization: token ${{ secrets.GH_ACTION_TOKEN_CLANG_FORMAT }}" \
+          -H "X-GitHub-Api-Version: 2022-11-28" \
+          -d "{\"body\": \"clang-format has detected some changes that need formatting\"}" \
+          "${API_URL}"

scripts/clang-format/clang-format-apply.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+BASE_BRANCH=$1
+CURRENT_BRANCH=$2
+
+# Save unified diff with 0 context
+git diff -U0 --name-only $BASE_BRANCH...$CURRENT_BRANCH > filestochange.diff
+
+cat filestochange.diff
+
+# Run clang-format in-place on .h and .cpp files
+while IFS= read -r line; do
+  if [ -n "$line" ]; then
+    if [[ "$line" == *.h ]] || [[ "$line" == *.cpp ]]; then
+      clang-format -i "$line"
+    fi
+  fi
+done < filestochange.diff
+
+rm filestochange.diff