fix(sync/git[remote]) Restore LibVCSException resilience

why: ``GitSync.remote()`` previously wrapped the underlying subprocess
call in ``try / except LibVCSException: return None`` so a corrupt
``.git/config`` or a locked file did not crash a ``vcspull sync``. The
``git remote show`` -> ``git remote -v`` rewrite dropped the wrapper,
so subprocess failures now leak as ``CommandError`` instead of degrading
gracefully.
what:
- Wrap ``self.cmd.remotes.get()`` in ``try / except exc.LibVCSException``
  and return ``None`` to preserve the old resilience contract.
- Document the suppression in the Notes block so future readers see why
  the wrapper exists.
- Add a regression test that mocks ``cmd.remotes.get`` to raise
  ``CommandError`` and asserts ``remote()`` returns ``None``.

Author: tony

src/libvcs/sync/git.py

@@ -676,15 +676,24 @@ def remote(self, name: str, **kwargs: t.Any) -> GitRemote | None:
 
         Notes
         -----
-        Uses ``git remote -v`` (via the cached remote manager) instead of
+        Uses ``git remote -v`` via the remote manager rather than
         ``git remote show -n``. ``git remote show`` also enumerates every
         remote-tracking ref, which pipes thousands of lines through the
         subprocess progress callback for repositories with large branch
         counts (e.g. ``openai/codex`` at 2,400+ refs) and can appear to
         hang. ``git remote -v`` is O(remotes) and cannot block on ref
         enumeration.
+
+        Subprocess failures from the underlying ``git remote -v`` are
+        suppressed and returned as ``None`` to preserve the resilience
+        contract callers relied on with the previous ``git remote show``
+        path (which wrapped the same call in ``try / except
+        LibVCSException``).
         """
-        remote_cmd = self.cmd.remotes.get(remote_name=name, default=None)
+        try:
+            remote_cmd = self.cmd.remotes.get(remote_name=name, default=None)
+        except exc.LibVCSException:
+            return None
         if remote_cmd is None:
             return None
 

tests/sync/test_git.py

@@ -1709,3 +1709,28 @@ def test_remote_is_fast_for_repos_with_many_refs(
     assert remote is not None
     assert remote.fetch_url, "fetch URL must be populated"
     assert elapsed < 5.0, f"remote() too slow: {elapsed:.2f}s with 500 fake refs"
+
+
+def test_remote_swallows_libvcs_exception(
+    git_repo: GitSync,
+    mocker: MockerFixture,
+) -> None:
+    """``GitSync.remote`` returns ``None`` when ``git remote -v`` fails.
+
+    The pre-rewrite implementation wrapped the underlying subprocess call
+    in ``try / except LibVCSException`` so a corrupt config or a locked
+    ``.git/config`` did not crash a ``vcspull sync``. The new path must
+    preserve that resilience -- callers should still see ``None`` rather
+    than a raised exception.
+    """
+    mocker.patch.object(
+        git_repo.cmd.remotes,
+        "get",
+        side_effect=exc.CommandError(
+            output="fatal: bad config",
+            returncode=128,
+            cmd="git remote --verbose",
+        ),
+    )
+
+    assert git_repo.remote("origin") is None