check if po files changed

.github/workflows/compile_catalog.yml

@@ -11,16 +11,25 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
+
+      - name: Check diff
+        run: |
+          REGEXP="^libresvip/.*\.po$"
+          PO_CHANGED_COUNT=$(git show --name-only | grep "$REGEXP" | wc -l)
+          PO_CHANGED=$([[ PO_CHANGED_COUNT -gt 0 ]] && echo "true" || echo "false")
+
+          echo "::set-output name=po_changed::$PO_CHANGED"
+
       - name: Set up Python
+        if: ${{ steps.check-diff.outputs.po_changed == 'true' }}
         uses: actions/setup-python@v5
         with:
           python-version: "3.12"
 
-      - name: Install babel
-        run: pip install babel setuptools
-
       - name: Compile catalogs
+        if: ${{ steps.check-diff.outputs.po_changed == 'true' }}
         run: |
+          pip install babel setuptools
           cd scripts
           python batch_compile_catalog.py