fix(cli): exclude desktop-managed backend from stale-dashboard kill

Fixes #37532

hermes_cli/main.py

@@ -7363,7 +7363,10 @@ def cmd_gui(args: argparse.Namespace):
     sys.exit(launch_result.returncode)
 
 
-def _find_stale_dashboard_pids() -> list[int]:
+def _find_stale_dashboard_pids(
+    *,
+    exclude_pids: set[int] | None = None,
+) -> list[int]:
     """Return PIDs of ``hermes dashboard`` processes other than ourselves.
 
     ``hermes dashboard`` is a long-lived server process commonly started and
@@ -7378,6 +7381,15 @@ def _find_stale_dashboard_pids() -> list[int]:
     it.  This helper is just the detection step; see
     ``_kill_stale_dashboard_processes`` for the kill.
 
+    *exclude_pids* is an optional set of PIDs that must never be returned.
+    This is used by the Hermes Desktop Electron app to protect its own
+    backend child process: when the desktop spawns ``hermes dashboard`` as
+    a backend and triggers an auto-update, the update must not kill the
+    dashboard that the desktop itself manages.  The desktop sets the
+    environment variable ``HERMES_DESKTOP_CHILD_PID`` on the spawned
+    backend process; ``_kill_stale_dashboard_processes`` reads it and
+    passes it here.  (#37532)
+
     Returns an empty list on any scan error (missing ps/wmic, timeout, etc.).
     """
     patterns = [
@@ -7453,6 +7465,8 @@ def _find_stale_dashboard_pids() -> list[int]:
     except (FileNotFoundError, subprocess.TimeoutExpired, OSError):
         return []
 
+    if exclude_pids:
+        dashboard_pids = [p for p in dashboard_pids if p not in exclude_pids]
     return dashboard_pids
 
 
@@ -7604,7 +7618,18 @@ def _kill_stale_dashboard_processes(
     launch args (--host, --port, --insecure, --tui, --no-open).  The user
     restarts it manually; a hint is printed.
     """
-    pids = _find_stale_dashboard_pids()
+    # When the Hermes Desktop Electron app spawns this dashboard as a
+    # backend child, it sets HERMES_DESKTOP_CHILD_PID so that the update
+    # path can skip killing the desktop-managed process.  (#37532)
+    exclude: set[int] | None = None
+    raw_pid = os.environ.get("HERMES_DESKTOP_CHILD_PID")
+    if raw_pid:
+        try:
+            exclude = {int(raw_pid)}
+        except (ValueError, TypeError):
+            pass
+
+    pids = _find_stale_dashboard_pids(exclude_pids=exclude)
     if not pids:
         return
 

tests/hermes_cli/test_update_stale_dashboard.py

@@ -185,6 +185,48 @@ class TestFindStaleDashboardPids:
             pids = _find_stale_dashboard_pids()
         assert pids == [12345]
 
+    def test_exclude_pids_filters_specified_pids(self):
+        """exclude_pids removes specific PIDs from the result — used by
+        the Desktop Electron app to protect its own backend child.  (#37532)
+        """
+        with patch("subprocess.run") as mock_run:
+            mock_run.return_value = MagicMock(
+                returncode=0,
+                stdout="\n".join([
+                    _ps_line(11111, "hermes dashboard --port 9119"),
+                    _ps_line(22222, "hermes dashboard --port 9120"),
+                    _ps_line(33333, "hermes dashboard --port 9121"),
+                ]) + "\n",
+                stderr="",
+            )
+            # Exclude the desktop-managed backend PID
+            pids = _find_stale_dashboard_pids(exclude_pids={22222})
+        assert 11111 in pids
+        assert 22222 not in pids
+        assert 33333 in pids
+
+    def test_exclude_pids_none_is_noop(self):
+        """Passing exclude_pids=None (the default) changes nothing."""
+        with patch("subprocess.run") as mock_run:
+            mock_run.return_value = MagicMock(
+                returncode=0,
+                stdout=_ps_line(12345, "hermes dashboard --port 9119") + "\n",
+                stderr="",
+            )
+            pids = _find_stale_dashboard_pids(exclude_pids=None)
+        assert pids == [12345]
+
+    def test_exclude_all_pids_returns_empty(self):
+        """If all matched PIDs are excluded, the result is empty."""
+        with patch("subprocess.run") as mock_run:
+            mock_run.return_value = MagicMock(
+                returncode=0,
+                stdout=_ps_line(12345, "hermes dashboard --port 9119") + "\n",
+                stderr="",
+            )
+            pids = _find_stale_dashboard_pids(exclude_pids={12345})
+        assert pids == []
+
 
 @pytest.mark.skipif(sys.platform == "win32", reason="POSIX kill semantics")
 class TestKillStaleDashboardPosix: