test(e2e): cover mixed-version rolling upgrades (#6975)

.github/workflows/e2e-upgrade.yml

@@ -49,8 +49,20 @@ env:
   UPGRADE_SOURCE_SHA256: 7c789386bf85278f865b8e0d359bf4edb84d5aa408cc3fa54a18c25ca74cd6e7
 
 jobs:
-  direct-upgrade:
-    name: Direct upgrade from rc.2
+  upgrade:
+    name: ${{ matrix.name }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - name: Direct upgrade from rc.2
+            cache_key: e2e-direct-upgrade
+            test: direct_upgrade_from_rc2_preserves_object_contracts
+            artifact: direct-upgrade
+          - name: Mixed-version rolling upgrade from rc.2
+            cache_key: e2e-mixed-version-upgrade
+            test: rolling_upgrade_from_rc2_preserves_mixed_version_contracts
+            artifact: mixed-version-upgrade
     runs-on: ubuntu-latest
     timeout-minutes: 60
     env:
@@ -64,7 +76,7 @@ jobs:
       - name: Setup Rust environment
         uses: ./.github/actions/setup
         with:
-          cache-shared-key: e2e-direct-upgrade
+          cache-shared-key: ${{ matrix.cache_key }}
           cache-save-if: ${{ github.ref == 'refs/heads/main' }}
           install-build-packaging-tools: "false"
 
@@ -89,17 +101,17 @@ jobs:
           cargo build --locked -p rustfs --bin rustfs
           : > target/debug/rustfs.features
 
-      - name: Run direct-upgrade compatibility test
+      - name: Run upgrade compatibility test
         run: |
           cargo test --locked -p e2e_test \
-            upgrade_compatibility_test::direct_upgrade_from_rc2_preserves_object_contracts \
+            "upgrade_compatibility_test::${{ matrix.test }}" \
             -- --ignored --exact --nocapture
 
       - name: Upload server logs
         if: always()
         uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6
         with:
-          name: direct-upgrade-server-logs-${{ github.run_number }}
+          name: ${{ matrix.artifact }}-server-logs-${{ github.run_number }}
           path: ${{ runner.temp }}/rustfs-upgrade-logs
           if-no-files-found: warn
           retention-days: 14