Keyboard protocol: Do not deliver a fake key release events on OS window focus out for engaged modifiers

Fixes #7196

docs/changelog.rst

@@ -86,6 +86,8 @@ Detailed list of changes
 - Remote control: Fix ``--match`` argument not working for @ls, @send-key,
   @set-background-image (:iss:`7192`)
 
+- Keyboard protocol: Do not deliver a fake key release events on OS window focus out for engaged modifiers (:iss:`7196`)
+
 
 0.32.2 [2024-02-12]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

glfw/glfw3.h

@@ -1288,6 +1288,9 @@ typedef struct GLFWkeyevent
     // For internal use only. On Linux it is the actual keycode reported by the windowing system, in contrast
     // to native_key which can be the result of a compose operation. On macOS it is the same as native_key.
     uint32_t native_key_id;
+
+    // True if this is a synthesized event on focus change
+    bool fake_event_on_focus_change;
 } GLFWkeyevent;
 
 /*! @brief The function pointer type for error callbacks.

glfw/window.c

@@ -57,7 +57,7 @@ void _glfwInputWindowFocus(_GLFWwindow* window, bool focused)
             if (window->activated_keys[i].key > 0 && window->activated_keys[i].action == GLFW_PRESS)
             {
                 const int native_key = _glfwPlatformGetNativeKeyForKey(window->activated_keys[i].key);
-                GLFWkeyevent ev = {.key = window->activated_keys[i].key, .native_key = native_key, .action = GLFW_RELEASE};
+                GLFWkeyevent ev = {.key = window->activated_keys[i].key, .native_key = native_key, .action = GLFW_RELEASE, .fake_event_on_focus_change = true};
                 _glfwInputKeyboard(window, &ev);
             }
         }

kitty/glfw-wrapper.h

@@ -1026,6 +1026,9 @@ typedef struct GLFWkeyevent
     // For internal use only. On Linux it is the actual keycode reported by the windowing system, in contrast
     // to native_key which can be the result of a compose operation. On macOS it is the same as native_key.
     uint32_t native_key_id;
+
+    // True if this is a synthesized event on focus change
+    bool fake_event_on_focus_change;
 } GLFWkeyevent;
 
 /*! @brief The function pointer type for error callbacks.

kitty/glfw.c

@@ -457,7 +457,7 @@ key_callback(GLFWwindow *w, GLFWkeyevent *ev) {
 #endif
     mods_at_last_key_or_button_event = ev->mods;
     global_state.callback_os_window->cursor_blink_zero_time = monotonic();
-    if (is_window_ready_for_callbacks()) on_key_input(ev);
+    if (is_window_ready_for_callbacks() && !ev->fake_event_on_focus_change) on_key_input(ev);
     global_state.callback_os_window = NULL;
     request_tick_callback();
 }