Reduce the number of spurious focus events

1) When performing operations known to cause lots of focus changes such
   as creating new sessions/windows or moving windows, forcibly ignore focus events

2) Track window focus state and dont report focus events when the state
   is unchanged by a focus_changed() call

This allows focus specific code to be restricted to just 2-3 places
instead of having to track every possible function that could change
focus.

Fixes #6083

kitty/boss.py

@@ -7,7 +7,7 @@ import json
 import os
 import re
 import sys
-from contextlib import suppress
+from contextlib import contextmanager, suppress
 from functools import partial
 from gettext import gettext as _
 from time import monotonic, sleep
@@ -17,6 +17,7 @@ from typing import (
     Callable,
     Container,
     Dict,
+    Generator,
     Iterable,
     Iterator,
     List,
@@ -381,6 +382,7 @@ class Boss:
         si = startup_sessions or create_sessions(get_options(), self.args, default_session=get_options().startup_session)
         focused_os_window = wid = 0
         token = os.environ.pop('XDG_ACTIVATION_TOKEN', '')
+        with Window.set_ignore_focus_changes_for_new_windows():
             for startup_session in si:
                 # The window state from the CLI options will override and apply to every single OS window in startup session
                 wstate = self.args.start_as if self.args.start_as and self.args.start_as != 'normal' else None
@@ -392,6 +394,8 @@ class Boss:
                 focus_os_window(focused_os_window, True, token)
             elif token and is_wayland() and wid:
                 focus_os_window(wid, True, token)
+        for w in self.all_windows:
+            w.ignore_focus_changes = False
 
     def add_os_window(
         self,
@@ -807,11 +811,24 @@ class Boss:
                     if not self.shutting_down:
                         self.mark_os_window_for_close(src_tab.os_window_id)
 
+    @contextmanager
+    def suppress_focus_change_events(self) -> Generator[None, None, None]:
+        changes = {}
+        for w in self.window_id_map.values():
+            changes[w] = w.ignore_focus_changes
+            w.ignore_focus_changes = True
+        try:
+            yield
+        finally:
+            for w, val in changes.items():
+                w.ignore_focus_changes = val
+
     def on_child_death(self, window_id: int) -> None:
         prev_active_window = self.active_window
         window = self.window_id_map.pop(window_id, None)
         if window is None:
             return
+        with self.suppress_focus_change_events():
             for close_action in window.actions_on_close:
                 try:
                     close_action(window)
@@ -838,6 +855,7 @@ class Boss:
                     traceback.print_exc()
             del window.actions_on_close[:], window.actions_on_removal[:]
             window = self.active_window
+
         if window is not prev_active_window:
             if prev_active_window is not None:
                 prev_active_window.focus_changed(False)
@@ -2498,6 +2516,7 @@ class Boss:
         src_tab = self.tab_for_window(window)
         if src_tab is None:
             return
+        with self.suppress_focus_change_events():
             if target_os_window_id == 'new':
                 target_os_window_id = self.add_os_window()
                 tm = self.os_window_map[target_os_window_id]

kitty/launch.py

@@ -435,7 +435,7 @@ force_window_launch = ForceWindowLaunch()
 non_window_launch_types = 'background', 'clipboard', 'primary'
 
 
-def launch(
+def _launch(
     boss: Boss,
     opts: LaunchCLIOptions,
     args: List[str],
@@ -588,14 +588,19 @@ def launch(
             tab = tab_for_window(boss, opts, target_tab)
         if tab is not None:
             watchers = load_watch_modules(opts.watcher)
-            new_window: Window = tab.new_window(env=env or None, watchers=watchers or None, is_clone_launch=is_clone_launch, **kw)
+            with Window.set_ignore_focus_changes_for_new_windows(opts.keep_focus):
+                new_window: Window = tab.new_window(
+                    env=env or None, watchers=watchers or None, is_clone_launch=is_clone_launch, **kw)
             if spacing:
                 patch_window_edges(new_window, spacing)
                 tab.relayout()
             if opts.color:
                 apply_colors(new_window, opts.color)
-            if opts.keep_focus and active:
+            if opts.keep_focus:
+                if active:
                     boss.set_active_window(active, switch_os_window_if_needed=True, for_keep_focus=True)
+                if not Window.initial_ignore_focus_changes_context_manager_in_operation:
+                    new_window.ignore_focus_changes = False
             if opts.logo:
                 new_window.set_logo(opts.logo, opts.logo_position or '', opts.logo_alpha)
             if opts.type == 'overlay-main':
@@ -604,6 +609,25 @@ def launch(
     return None
 
 
+def launch(
+    boss: Boss,
+    opts: LaunchCLIOptions,
+    args: List[str],
+    target_tab: Optional[Tab] = None,
+    force_target_tab: bool = False,
+    active: Optional[Window] = None,
+    is_clone_launch: str = '',
+    rc_from_window: Optional[Window] = None,
+) -> Optional[Window]:
+    active = active or boss.active_window_for_cwd
+    if opts.keep_focus and active:
+        orig, active.ignore_focus_changes = active.ignore_focus_changes, True
+    try:
+        return _launch(boss, opts, args, target_tab, force_target_tab, active, is_clone_launch, rc_from_window)
+    finally:
+        if opts.keep_focus and active:
+            active.ignore_focus_changes = orig
+
 @run_once
 def clone_safe_opts() -> FrozenSet[str]:
     return frozenset((

kitty/window.py

@@ -7,7 +7,7 @@ import re
 import sys
 import weakref
 from collections import deque
-from contextlib import suppress
+from contextlib import contextmanager, suppress
 from enum import Enum, IntEnum, auto
 from functools import lru_cache, partial
 from gettext import gettext as _
@@ -19,6 +19,7 @@ from typing import (
     Callable,
     Deque,
     Dict,
+    Generator,
     Iterable,
     List,
     NamedTuple,
@@ -542,6 +543,22 @@ class Window:
 
     window_custom_type: str = ''
     overlay_type = OverlayType.transient
+    initial_ignore_focus_changes: bool = False
+    initial_ignore_focus_changes_context_manager_in_operation: bool = False
+
+    @classmethod
+    @contextmanager
+    def set_ignore_focus_changes_for_new_windows(cls, value: bool = True) -> Generator[None, None, None]:
+        if cls.initial_ignore_focus_changes_context_manager_in_operation:
+            yield
+        else:
+            orig, cls.initial_ignore_focus_changes = cls.initial_ignore_focus_changes, value
+            cls.initial_ignore_focus_changes_context_manager_in_operation = True
+            try:
+                yield
+            finally:
+                cls.initial_ignore_focus_changes = orig
+                cls.initial_ignore_focus_changes_context_manager_in_operation = False
 
     def __init__(
         self,
@@ -560,6 +577,7 @@ class Window:
         else:
             self.watchers = global_watchers().copy()
         self.last_focused_at = 0.
+        self.is_focused: bool = False
         self.last_resized_at = 0.
         self.started_at = monotonic()
         self.current_remote_data: List[str] = []
@@ -574,6 +592,7 @@ class Window:
         self.pty_resized_once = False
         self.last_reported_pty_size = (-1, -1, -1, -1)
         self.needs_attention = False
+        self.ignore_focus_changes = self.initial_ignore_focus_changes
         self.override_title = override_title
         self.default_title = os.path.basename(child.argv[0] or appname)
         self.child_title = self.default_title
@@ -993,8 +1012,9 @@ class Window:
             return False
 
     def focus_changed(self, focused: bool) -> None:
-        if self.destroyed:
+        if self.destroyed or self.ignore_focus_changes or self.is_focused == focused:
             return
+        self.is_focused = focused
         call_watchers(weakref.ref(self), 'on_focus_change', {'focused': focused})
         for c in self.actions_on_focus_change:
             try: