fixed checks for pull requests

Author: bigabig

.github/workflows/frontend_checks.yml

@@ -19,6 +19,8 @@ jobs:
       COMPOSE_PROFILES: "weaviate,ray,background,backend,frontend"
       RAY_CONFIG: "config_gpu.yaml"
       JWT_SECRET: ${{ secrets.JWT_SECRET }}
+      BACKEND_HAS_NEW_REQUIREMENTS: false
+      RAY_HAS_NEW_REQUIREMENTS: false
     steps:
       - uses: actions/checkout@v3
       - name: Checkout PR
@@ -28,21 +30,19 @@ jobs:
         run: gh pr checkout ${{ github.event.pull_request.number }}
       - name: Check for new backend requirements
         id: check_backend_requirements
+        if: github.event_name == 'pull_request'
         run: |
-          if git diff --name-only ${{ github.event.before }} ${{ github.sha }} | grep -q -e '^backend/requirements.txt' -e '^backend/environment.yml'; then
-            echo "Backend has new requirements"
+          base_branch=$(git merge-base origin/${{ github.event.pull_request.base.ref }} HEAD)
+          if git diff --name-only $base_branch HEAD | grep -q -e '^backend/requirements.txt' -e '^backend/environment.yml'; then
             echo "BACKEND_HAS_NEW_REQUIREMENTS=true" >> $GITHUB_ENV
-          else
-            echo "BACKEND_HAS_NEW_REQUIREMENTS=false" >> $GITHUB_ENV
           fi
       - name: Check for new ray requirements
         id: check_ray_requirements
+        if: github.event_name == 'pull_request'
         run: |
-          if git diff --name-only ${{ github.event.before }} ${{ github.sha }} | grep -q -e '^backend/src/app/preprocessing/ray_model_worker/requirements.txt'; then
-            echo "Ray has new requirements"
+          base_branch=$(git merge-base origin/${{ github.event.pull_request.base.ref }} HEAD)
+          if git diff --name-only $base_branch HEAD | grep -q -e '^backend/src/app/preprocessing/ray_model_worker/requirements.txt'; then
             echo "RAY_HAS_NEW_REQUIREMENTS=true" >> $GITHUB_ENV
-          else
-            echo "RAY_HAS_NEW_REQUIREMENTS=false" >> $GITHUB_ENV
           fi
       - name: Prepare environment
         run: |