Server(fix): Preserve owned endpoints after failed cleanup

Check both exit status and stderr before removing an owned server's socket directory. Keep completed failures visible and the endpoint available for retry without changing legacy Server.kill behavior.

Author: tony

src/libtmux/server.py

@@ -318,11 +318,17 @@ def owned(
             )
         finally:
             if socket_path.exists():
-                Server(
+                proc = Server(
                     socket_path=socket_path,
                     tmux_bin=tmux_bin,
                     timeout=timeout,
-                ).kill()
+                ).cmd("kill-server")
+                if (proc.returncode or proc.stderr) and not _is_daemon_not_up_error(
+                    " ".join(proc.stderr)
+                ):
+                    raise exc.LibTmuxException(
+                        proc.stderr or f"Server cleanup exited with {proc.returncode}"
+                    )
             shutil.rmtree(directory)
 
     def __enter__(self) -> Self:

tests/test_server.py

@@ -518,6 +518,52 @@ def run(
         shutil.rmtree(socket_path.parent)
 
 
+def test_owned_server_preserves_socket_after_silent_cleanup_failure(
+    server: Server,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """A completed failure without stderr remains visible and retryable."""
+    run_command = common.run_command
+    completed = run_command("-V", tmux_bin=server.tmux_bin)
+    removed: list[pathlib.Path] = []
+
+    def run(
+        *args: object,
+        tmux_bin: str | None = None,
+        timeout: float | None = None,
+    ) -> common.CommandResult:
+        if "kill-server" in args:
+            return common.CommandResult(
+                cmd=[str(arg) for arg in args],
+                stdout=[],
+                stderr=[],
+                returncode=7,
+                process=completed.process,
+            )
+        return run_command(*args, tmux_bin=tmux_bin, timeout=timeout)
+
+    try:
+        with monkeypatch.context() as patch:
+            # Keep the endpoint reachable even if the assertion exposes a regression.
+            patch.setattr(shutil, "rmtree", removed.append)
+            with (
+                pytest.raises(
+                    exc.LibTmuxException, match="Server cleanup exited with 7"
+                ),
+                Server.owned(tmux_bin=server.tmux_bin) as owned,
+            ):
+                owned.new_session()
+                assert owned.socket_path is not None
+                socket_path = pathlib.Path(owned.socket_path)
+                patch.setattr(common, "run_command", run)
+            assert not removed
+            assert socket_path.exists()
+            assert owned.is_alive()
+    finally:
+        owned.kill()
+        shutil.rmtree(socket_path.parent)
+
+
 class StartDirectoryTestFixture(t.NamedTuple):
     """Test fixture for start_directory parameter testing."""