Swift: infrastructure for upgrade/downgrade scripts

.github/workflows/swift.yml

@@ -111,4 +111,19 @@ jobs:
       - uses: actions/upload-artifact@v3
         with:
           name: swift-generated-cpp-files
-          path: swift/generated-cpp-files/**
+          path: swift/generated-cpp-files/**
+  qlformat:
+    runs-on: ubuntu-latest
+    needs: changes
+    if: ${{ needs.changes.outputs.ql == 'true' }}
+    steps:
+      - uses: actions/checkout@v3
+      - uses: ./.github/actions/fetch-codeql
+      - name: Check QL formatting
+        run: find swift/ql "(" -name "*.ql" -or -name "*.qll" ")" -print0 | xargs -0 codeql query format --check-only
+  database-upgrade-scripts:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: ./.github/actions/fetch-codeql
+      - uses: ./swift/actions/database-upgrade-scripts

swift/actions/database-upgrade-scripts/action.yml

@@ -0,0 +1,23 @@
+name: Check Swift database upgrade/downgrade scripts
+runs:
+  using: composite
+  steps:
+    - name: Check upgrade scripts
+      shell: bash
+      working-directory: swift
+      run: |
+        echo > empty.trap
+        codeql dataset import -S ql/lib/upgrades/initial/swift.dbscheme testdb empty.trap
+        codeql dataset upgrade testdb --additional-packs ql/lib
+        diff -q testdb/swift.dbscheme ql/lib/swift.dbscheme
+    - name: Check downgrade scripts
+      shell: bash
+      working-directory: swift
+      run: |
+        echo > empty.trap
+        rm -rf testdb
+        codeql dataset import -S ql/lib/swift.dbscheme testdb empty.trap
+        codeql resolve upgrades --format=lines --allow-downgrades --additional-packs downgrades \
+         --dbscheme=ql/lib/swift.dbscheme --target-dbscheme=downgrades/initial/swift.dbscheme |
+         xargs -r codeql execute upgrades testdb
+        diff -q testdb/swift.dbscheme downgrades/initial/swift.dbscheme

swift/downgrades/qlpack.yml

@@ -0,0 +1,4 @@
+name: codeql/swift-downgrades
+groups: swift
+downgrades: .
+library: true