Version sync: skip syncing versions when lsremote fails (#12540)

Currently, if lsremote fails, we are returning an empty list of branches
and tags, which is interpreted by our system as if the branches/tags
were deleted, which is incorrect.

I was thinking on raising this exception to the user, but I decided
against it, as the user won't be able to fix the problem (it could be a
temporal issue), if the repo isn't correctly configured, they will get
the error when trying to clone the repo.

---------

Co-authored-by: Manuel Kaufmann <[email protected]>

Author: stsewd

readthedocs/projects/exceptions.py

@@ -24,6 +24,7 @@ class RepositoryError(BuildUserError):
     FAILED_TO_CHECKOUT = "project:repository:checkout-failed"
     GENERIC = "project:repository:generic-error"
     UNSUPPORTED_VCS = "project:repository:unsupported-vcs"
+    FAILED_TO_GET_VERSIONS = "project:repository:failed-to-get-versions"
 
 
 class SyncRepositoryLocked(BuildAppError):

readthedocs/projects/tasks/mixins.py

@@ -44,10 +44,17 @@ def sync_versions(self, vcs_repository):
         # check this here and do not depend on ``vcs_repository``.
         sync_tags = not self.data.project.has_feature(Feature.SKIP_SYNC_TAGS)
         sync_branches = not self.data.project.has_feature(Feature.SKIP_SYNC_BRANCHES)
-        branches, tags = vcs_repository.lsremote(
-            include_tags=sync_tags,
-            include_branches=sync_branches,
-        )
+        try:
+            branches, tags = vcs_repository.lsremote(
+                include_tags=sync_tags,
+                include_branches=sync_branches,
+            )
+        except RepositoryError:
+            log.warning(
+                "Error running lsremote to get versions from the repository.",
+                exc_info=True,
+            )
+            return
 
         tags_data = [
             {

readthedocs/projects/tests/test_build_tasks.py

@@ -3040,3 +3040,10 @@ def test_check_duplicate_reserved_version_latest(self, on_failure, verbose_name)
         exception = on_failure.call_args[0][0]
         assert isinstance(exception, RepositoryError) == True
         assert exception.message_id == RepositoryError.DUPLICATED_RESERVED_VERSIONS
+
+    @mock.patch("readthedocs.builds.tasks.sync_versions_task")
+    @mock.patch("readthedocs.vcs_support.backends.git.Backend.lsremote")
+    def test_skip_sync_version_task_if_lsremote_fails(self, lsremote, sync_versions_task):
+        lsremote.side_effect = RepositoryError(RepositoryError.FAILED_TO_GET_VERSIONS)
+        self._trigger_sync_repository_task()
+        sync_versions_task.assert_not_called()

readthedocs/rtd_tests/tests/test_backend.py

@@ -146,6 +146,23 @@ def test_git_lsremote_branches_only(self):
             {branch.verbose_name: branch.identifier for branch in repo_branches},
         )
 
+    def test_git_lsremote_fails(self):
+        version = self.project.versions.first()
+        repo = self.project.vcs_repo(environment=self.build_environment, version=version)
+        with mock.patch(
+            "readthedocs.vcs_support.backends.git.Backend.run",
+            return_value=(1, "Error", ""),
+        ):
+            with self.assertRaises(RepositoryError) as e:
+                repo.lsremote(
+                    include_tags=True,
+                    include_branches=True,
+                )
+            self.assertEqual(
+                e.exception.message_id,
+                RepositoryError.FAILED_TO_GET_VERSIONS,
+            )
+
     def test_git_update_and_checkout(self):
         version = self.project.versions.first()
         repo = self.project.vcs_repo(environment=self.build_environment, version=version)

readthedocs/vcs_support/backends/git.py

@@ -397,7 +397,10 @@ def lsremote(self, include_tags=True, include_branches=True):
         cmd = ["git", "ls-remote", *extra_args, self.repo_url]
 
         self.check_working_dir()
-        _, stdout, _ = self.run(*cmd, demux=True, record=False)
+        exit_code, stdout, _ = self.run(*cmd, demux=True, record=False)
+
+        if exit_code != 0:
+            raise RepositoryError(message_id=RepositoryError.FAILED_TO_GET_VERSIONS)
 
         branches = []
         # Git has two types of tags: lightweight and annotated.