test: assert digest rollback fails before side effects

infra/deploy/test_rollback.py

@@ -1,7 +1,11 @@
+import json
 import subprocess
+import sys
 import unittest
+from types import SimpleNamespace
 from unittest.mock import patch
 
+import rollback
 from rollback import image_restore_plan, require_tag_rollback, tag_previous_images, verify_previous_images
 
 
@@ -72,6 +76,46 @@ class RollbackPlanTests(unittest.TestCase):
                 tag_previous_images(plan)
         run_mock.assert_not_called()
 
+    def test_digest_rollback_fails_before_stopping_or_changing_references(self):
+        backend_id = "sha256:" + "a" * 64
+        opensearch_id = "sha256:" + "b" * 64
+        digest = "registry/backend@sha256:" + "c" * 64
+        manifest = {
+            "images": {
+                "backend": {"configured": digest, "image_id": backend_id},
+                "opensearch": self.manifest["images"]["opensearch"],
+            },
+            "deployment_files": {
+                "deploy/production/compose.yaml": "compose-hash",
+                "deploy/production/Caddyfile": "caddy-hash",
+            },
+        }
+        rendered = {
+            "services": {
+                "backend": {"image": digest},
+                "opensearch": {"image": self.configured["opensearch"]},
+            }
+        }
+        fake_archive = SimpleNamespace(
+            digest=lambda path: "compose-hash" if path.name == "compose.yaml" else "caddy-hash",
+            verify_archive=lambda _backup: manifest,
+        )
+        backup = rollback.BACKUP_DIR / "synthetic.tar.gz"
+        with (
+            patch("rollback.Path.is_file", return_value=True),
+            patch("rollback.Path.is_symlink", return_value=False),
+            patch("rollback.Path.stat", return_value=SimpleNamespace(st_uid=0, st_mode=0o100600)),
+            patch("rollback.compose", return_value=json.dumps(rendered)) as compose_mock,
+            patch("rollback.run", side_effect=[backend_id, backend_id, opensearch_id]) as run_mock,
+            patch.dict(sys.modules, {"archive": fake_archive}),
+        ):
+            with self.assertRaisesRegex(ValueError, "not supported safely"):
+                rollback.rollback(backup, data_compatible=True)
+        compose_mock.assert_called_once_with("config", "--format", "json", capture=True)
+        self.assertEqual(run_mock.call_count, 3)
+        self.assertTrue(all(call.args[0][:3] == ["docker", "image", "inspect"]
+                            for call in run_mock.call_args_list))
+
     def test_tag_rollback_keeps_existing_image_tag_operation(self):
         plan = image_restore_plan(self.manifest, self.configured)
         with patch("rollback.run") as run_mock: