...

docs/launch.rst

@@ -122,47 +122,48 @@ create :file:`~/.config/kitty/mywatcher.py` and use :option:`launch --watcher` =
 .. code-block:: python
 
     # ~/.config/kitty/mywatcher.py
-    from typing import Any, Dict
+    from typing import Any
 
     from kitty.boss import Boss
     from kitty.window import Window
 
 
-    def on_load(boss: Boss) -> None:
+    def on_load(boss: Boss, data: dict[str, Any]) -> None:
         # This is a special function that is called just once when this watcher
         # module is first loaded, can be used to perform any initializztion/one
-        # time setup.
+        # time setup. Any exceptions in this function are printed to kitty's
+        # STDERR but otherwise ignored.
         ...
 
-    def on_resize(boss: Boss, window: Window, data: Dict[str, Any]) -> None:
+    def on_resize(boss: Boss, window: Window, data: dict[str, Any]) -> None:
         # Here data will contain old_geometry and new_geometry
         # Note that resize is also called the first time a window is created
         # which can be detected as old_geometry will have all zero values, in
         # particular, old_geometry.xnum and old_geometry.ynum will be zero.
         ...
 
-    def on_focus_change(boss: Boss, window: Window, data: Dict[str, Any])-> None:
+    def on_focus_change(boss: Boss, window: Window, data: dict[str, Any])-> None:
         # Here data will contain focused
         ...
 
-    def on_close(boss: Boss, window: Window, data: Dict[str, Any])-> None:
+    def on_close(boss: Boss, window: Window, data: dict[str, Any])-> None:
         # called when window is closed, typically when the program running in
         # it exits
         ...
 
-    def on_set_user_var(boss: Boss, window: Window, data: Dict[str, Any]) -> None:
+    def on_set_user_var(boss: Boss, window: Window, data: dict[str, Any]) -> None:
         # called when a "user variable" is set or deleted on a window. Here
         # data will contain key and value
         ...
 
-    def on_title_change(boss: Boss, window: Window, data: Dict[str, Any]) -> None:
+    def on_title_change(boss: Boss, window: Window, data: dict[str, Any]) -> None:
         # called when the window title is changed on a window. Here
         # data will contain title and from_child. from_child will be True
         # when a title change was requested via escape code from the program
         # running in the terminal
         ...
 
-    def on_cmd_startstop(boss: Boss, window: Window, data: Dict[str, Any]) -> None:
+    def on_cmd_startstop(boss: Boss, window: Window, data: dict[str, Any]) -> None:
         # called when the shell starts/stops executing a command. Here
         # data will contain is_start, cmdline and time.
         ...
@@ -177,7 +178,7 @@ would pass to ``kitten @``. For example:
 
 .. code-block:: python
 
-    def on_resize(boss: Boss, window: Window, data: Dict[str, Any]) -> None:
+    def on_resize(boss: Boss, window: Window, data: dict[str, Any]) -> None:
         # send some text to the resized window
         boss.call_remote_control(window, ('send-text', f'--match=id:{window.id}', 'hello world'))
 

kitty/launch.py

@@ -439,7 +439,11 @@ def load_watch_modules(watchers: Iterable[str]) -> Optional[Watchers]:
             watcher_modules[path] = m
             w = m.get('on_load')
             if callable(w):
-                w(boss)
+                try:
+                    w(boss, {})
+                except Exception:
+                    import traceback
+                    traceback.print_exc()
         if m is False:
             continue
         w = m.get('on_close')