Don't sync the release for downgrades

Compare the version to propose with version in the specfile
of the particular branch.
Fixes packit#2208

packit/api.py

@@ -1018,6 +1018,20 @@ def sync_release(
                     "Using the downstream specfile instead of the upstream one.",
                 )
                 self.up.set_specfile(self.dg.specfile)
+            try:
+                downstream_spec_ver = self.dg.get_specfile_version()
+                if compare_versions(version, downstream_spec_ver) < 0:
+                    msg = (
+                        f"Downstream specfile version {downstream_spec_ver} is lower "
+                        f"than the version to propose ({version}). Skipping the update."
+                    )
+                    logger.debug(msg)
+                    raise ReleaseSkippedPackitException(msg)
+                self.dg.refresh_specfile()
+
+            except FileNotFoundError:
+                # no downstream spec file
+                pass
 
             self.up.run_action(
                 actions=ActionName.post_upstream_clone,

packit/base_git.py

@@ -11,6 +11,7 @@
 
 import git
 import requests
+import rpm
 from git import GitCommandError, PushInfo
 from ogr.abstract import AccessLevel, GitProject, PullRequest
 from specfile import Specfile
@@ -138,6 +139,15 @@ def absolute_source_dir(self) -> Path:
         """
         return self.absolute_specfile_dir
 
+    def get_specfile_version(self) -> str:
+        """provide version from specfile"""
+        # we need to get the version from rpm spec header
+        # (as the version tag might not be present directly in the specfile,
+        # but e.g. imported)
+        version = self.specfile.rpm_spec.sourceHeader[rpm.RPMTAG_VERSION]
+        logger.info(f"Version in spec file is {version!r}.")
+        return version
+
     def create_branch(
         self,
         branch_name: str,

packit/upstream.py

@@ -13,7 +13,6 @@
 from typing import Optional, Union
 
 import git
-import rpm
 
 from packit.actions import ActionName
 from packit.base_git import PackitRepositoryBase
@@ -256,15 +255,6 @@ def get_latest_released_version(self) -> Optional[str]:
         logger.info(f"Version in upstream registries is {version!r}.")
         return version
 
-    def get_specfile_version(self) -> str:
-        """provide version from specfile"""
-        # we need to get the version from rpm spec header
-        # (as the version tag might not be present directly in the specfile,
-        # but e.g. imported)
-        version = self.specfile.rpm_spec.sourceHeader[rpm.RPMTAG_VERSION]
-        logger.info(f"Version in spec file is {version!r}.")
-        return version
-
     def get_version_from_action(self) -> str:
         """provide version from action"""
         action_output = self.get_output_from_action(

tests/unit/test_api.py

@@ -16,7 +16,7 @@
 from packit.config.config import Config
 from packit.copr_helper import CoprHelper
 from packit.distgit import DistGit
-from packit.exceptions import PackitException
+from packit.exceptions import PackitException, ReleaseSkippedPackitException
 from packit.local_project import LocalProjectBuilder
 from packit.patches import PatchGenerator
 from packit.sync import SyncFilesItem
@@ -340,6 +340,22 @@ def test_sync_release_check_pr_instructions(api_mock):
     api_mock.sync_release(version="1.1", dist_git_branch="_", add_pr_instructions=True)
 
 
+def test_sync_release_downgrade(api_mock):
+    flexmock(PatchGenerator).should_receive("undo_identical")
+    api_mock.up.should_receive("get_specfile_version").and_return("0")
+    api_mock.up.should_receive("specfile").and_return(
+        flexmock().should_receive("reload").mock(),
+    )
+    api_mock.up.package_config.should_receive("get_package_names_as_env").and_return({})
+    api_mock.dg.should_receive("get_specfile_version").and_return("1.1")
+    with pytest.raises(ReleaseSkippedPackitException):
+        api_mock.sync_release(
+            version="1.0",
+            dist_git_branch="_",
+            add_pr_instructions=True,
+        )
+
+
 @pytest.mark.parametrize(
     "resolved_bugs, result",
     [