Stop invalidating sudo timestamp on mode exit

CONTRIBUTING.md

@@ -63,6 +63,8 @@ repository documents.
 - The application starts in Read-only Mode.
 - Mutating actions require Privileged Mode, and a Pre-edit Backup must exist
   before writes are enabled.
+- Leaving Privileged Mode clears only application permission and undo/redo
+  session state; it must not alter sudo's cached timestamp.
 - Default Entries are protected from mutation and must remain first when file
   order changes.
 - All privileged writes go through `HostsManager`.

README.md

@@ -83,8 +83,8 @@ sorting, DNS refresh, movement, undo, and redo.
   unchanged.
 - Pre-edit Backups are not listed or restored by the TUI and have no retention
   management. Manual recovery is documented in the user guide.
-- Leaving Privileged Mode currently invalidates the user's cached sudo
-  timestamp. This is [tracked for removal](https://git.s1q.dev/phg/hosts/issues/4).
+- Leaving Privileged Mode clears the application's session state but does not
+  alter the user's cached sudo timestamp.
 - Serialization preserves Host Entries and comments semantically, but
   normalizes spacing, comment placement, and blank lines. It is not a
   byte-for-byte round trip.

docs/user-guide.md

@@ -176,11 +176,8 @@ selection of the newest backup without inspecting it.
 
 Press `Ctrl+E` again. The application clears its undo/redo history and forgets
 which Pre-edit Backup belongs to the session. The backup file remains in the
-temporary directory.
-
-Leaving Privileged Mode currently runs `sudo -k`, which invalidates your cached
-sudo timestamp for other terminal sessions as well. This behavior is
-[tracked for removal](https://git.s1q.dev/phg/hosts/issues/4).
+temporary directory. It does not alter your cached sudo timestamp, including
+authorization used by other terminal sessions.
 
 ## Configuration
 

src/hosts/core/manager.py

@@ -27,7 +27,7 @@ class PermissionManager:
     """
     Manages sudo permissions for hosts file editing.
 
-    Handles requesting, validating, and releasing elevated permissions
+    Handles requesting, validating, and tracking the elevated permissions
     needed for modifying the system hosts file.
     """
 
@@ -101,13 +101,8 @@ class PermissionManager:
         except Exception:
             return False
 
-    def release_sudo(self) -> None:
-        """Release sudo permissions."""
-        try:
-            subprocess.run(["sudo", "-k"], capture_output=True, timeout=5)
-        except Exception:
-            pass
-        finally:
+    def clear_permission_state(self) -> None:
+        """Clear application permission state without changing sudo's timestamp."""
         self.has_sudo = False
         self._sudo_validated = False
 
@@ -170,7 +165,7 @@ class HostsManager:
 
     def exit_edit_mode(self) -> Tuple[bool, str]:
         """
-        Exit edit mode and release permissions.
+        Exit edit mode and clear application permission state.
 
         Returns:
             Tuple of (success, message)
@@ -179,7 +174,7 @@ class HostsManager:
             return True, "Already in read-only mode"
 
         try:
-            self.permission_manager.release_sudo()
+            self.permission_manager.clear_permission_state()
             self.edit_mode = False
             self._backup_path = None
             self.undo_redo_history.clear_history()  # Clear undo/redo history when exiting edit mode

tests/test_app.py

@@ -1,7 +1,7 @@
 """Tests for application-level authorization flow."""
 
 from contextlib import contextmanager
-from unittest.mock import Mock
+from unittest.mock import Mock, patch
 
 from textual.app import SuspendNotSupported
 
@@ -125,3 +125,22 @@ class TestPrivilegedModeAuthorization:
         app.update_status.assert_called_once_with(
             "Interactive authorization requires terminal suspension; remaining in Read-only Mode."
         )
+
+    @patch("src.hosts.core.manager.subprocess.run")
+    def test_leaving_privileged_mode_preserves_the_sudo_timestamp(self, mock_run):
+        """Test Ctrl+E clears app state without invalidating sudo globally."""
+        app = HostsManagerApp()
+        app.edit_mode = True
+        app.manager.edit_mode = True
+        app.manager.permission_manager.has_sudo = True
+        app.manager.permission_manager._sudo_validated = True
+        app.update_status = Mock()
+
+        app.action_toggle_edit_mode()
+
+        assert not app.edit_mode
+        assert not app.manager.edit_mode
+        assert not app.manager.permission_manager.has_sudo
+        assert not app.manager.permission_manager._sudo_validated
+        mock_run.assert_not_called()
+        app.update_status.assert_called_once_with("Edit mode disabled")

tests/test_manager.py

@@ -12,6 +12,7 @@ from pathlib import Path
 from unittest.mock import Mock, patch
 from src.hosts.core.manager import PermissionManager, HostsManager
 from src.hosts.core.models import HostEntry, HostsFile
+from src.hosts.core.commands import ToggleEntryCommand
 
 
 class TestPermissionManager:
@@ -183,32 +184,17 @@ class TestPermissionManager:
         assert not result
 
     @patch("subprocess.run")
-    def test_release_sudo(self, mock_run):
-        """Test releasing sudo permissions."""
+    def test_clear_permission_state_preserves_global_sudo_timestamp(self, mock_run):
+        """Test exiting Privileged Mode preserves the global sudo timestamp."""
         pm = PermissionManager()
         pm.has_sudo = True
         pm._sudo_validated = True
 
-        pm.release_sudo()
+        pm.clear_permission_state()
 
         assert not pm.has_sudo
         assert not pm._sudo_validated
-        mock_run.assert_called_once_with(["sudo", "-k"], capture_output=True, timeout=5)
-
-    @patch("subprocess.run")
-    def test_release_sudo_exception(self, mock_run):
-        """Test releasing sudo with exception."""
-        mock_run.side_effect = Exception("Test error")
-
-        pm = PermissionManager()
-        pm.has_sudo = True
-        pm._sudo_validated = True
-
-        pm.release_sudo()
-
-        # Should still reset state even if command fails
-        assert not pm.has_sudo
-        assert not pm._sudo_validated
+        mock_run.assert_not_called()
 
 
 class TestHostsManager:
@@ -306,14 +292,25 @@ class TestHostsManager:
             assert not manager.edit_mode
 
     def test_exit_edit_mode_success(self):
-        """Test exiting edit mode successfully."""
+        """Test exit clears the Privileged Mode session state."""
         with tempfile.NamedTemporaryFile() as temp_file:
             manager = HostsManager(temp_file.name)
             manager.edit_mode = True
             manager._backup_path = Path("/tmp/backup")
+            hosts_file = HostsFile(
+                entries=[
+                    HostEntry("192.0.2.1", ["example.test"]),
+                    HostEntry("192.0.2.2", ["example-two.test"]),
+                ]
+            )
+            manager.undo_redo_history.execute_command(ToggleEntryCommand(0), hosts_file)
+            manager.undo_redo_history.execute_command(ToggleEntryCommand(1), hosts_file)
+            manager.undo_redo_history.undo(hosts_file)
+            assert manager.can_undo()
+            assert manager.can_redo()
 
             # Mock permission manager
-            manager.permission_manager.release_sudo = Mock()
+            manager.permission_manager.clear_permission_state = Mock()
 
             success, message = manager.exit_edit_mode()
 
@@ -321,7 +318,9 @@ class TestHostsManager:
             assert "disabled" in message
             assert not manager.edit_mode
             assert manager._backup_path is None
-            manager.permission_manager.release_sudo.assert_called_once()
+            assert not manager.can_undo()
+            assert not manager.can_redo()
+            manager.permission_manager.clear_permission_state.assert_called_once()
 
     def test_exit_edit_mode_not_in_edit(self):
         """Test exiting edit mode when not in edit mode."""
@@ -341,7 +340,7 @@ class TestHostsManager:
             manager.edit_mode = True
 
             # Mock permission manager to raise exception
-            manager.permission_manager.release_sudo = Mock(
+            manager.permission_manager.clear_permission_state = Mock(
                 side_effect=Exception("Test error")
             )