[GitHub Actions] Cleanup untranslated .po files

.ci/githubactions/check_po_base_unchanged.sh

@@ -0,0 +1,17 @@
+#!/bin/sh
+
+# Expects input of $1 base file and $2 .po file
+
+diff -q --ignore-trailing-space --ignore-blank-lines \
+     --ignore-matching-lines='^# .*' \
+     --ignore-matching-lines='^#$' \
+     --ignore-matching-lines='^#, fuzzy$' \
+     --ignore-matching-lines='^".*\:.*"' \
+     "$1" "$2" &>/dev/null
+result=$?
+
+if [ $result -eq 0 ]; then
+  printf '%s\0' "$2"
+fi
+
+exit 0

.github/workflows/crowdin_download_translations.yml

@@ -74,6 +74,18 @@ jobs:
           CROWDIN_PROJECT_ID: ${{ vars.CROWDIN_PROJECT_ID }}
           CROWDIN_PERSONAL_TOKEN: ${{ secrets.CROWDIN_PERSONAL_TOKEN }}
 
+      - name: Cleanup untranslated .po files
+        if: success() && (github.repository == 'Warzone2100/warzone2100')
+        run: |
+          # For warzone2100.pot:
+          find po -name '*.po' -type f \
+            -exec \
+            .ci/githubactions/check_po_base_unchanged.sh 'po/warzone2100.pot' '{}' ';' | xargs -r0 -I {} rm "{}"
+          # For warzone2100_guide.pot:
+          find po/guide -name '*.po' -type f \
+            -exec \
+            .ci/githubactions/check_po_base_unchanged.sh 'po/guide/warzone2100_guide.pot' '{}' ';' | xargs -r0 -I {} rm "{}"
+
       - name: Publish any changes to translations to l10n_master branch
         if: success() && (github.repository == 'Warzone2100/warzone2100')
         id: pushupdates