Have the :opt:confirm_os_window_close option also apply when closing tabs with multiple windows

Fixes #2857

docs/changelog.rst

@@ -49,6 +49,9 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 
 - Fix incorrect centering when a PUA or symbol glyph is followed by more than one space
 
+- Have the :opt:`confirm_os_window_close` option also apply when closing tabs
+  with multiple windows (:iss:`2857`)
+
 
 0.18.1 [2020-06-23]
 --------------------

kitty/boss.py

@@ -444,8 +444,32 @@ class Boss:
     def close_tab(self, tab: Optional[Tab] = None) -> None:
         tab = tab or self.active_tab
         if tab:
-            for window in tab:
+            self.confirm_tab_close(tab)
+
+    def confirm_tab_close(self, tab: Tab) -> None:
+        windows = tuple(tab)
+        needs_confirmation = self.opts.confirm_os_window_close > 0 and len(windows) >= self.opts.confirm_os_window_close
+        if not needs_confirmation:
+            for window in windows:
                 self.close_window(window)
+            return
+        self._run_kitten('ask', ['--type=yesno', '--message', _(
+            'Are you sure you want to close this tab, it has {}'
+            ' windows running?').format(len(windows))],
+            window=tab.active_window,
+            custom_callback=partial(self.handle_close_tab_confirmation, tab.id)
+        )
+
+    def handle_close_tab_confirmation(self, tab_id: int, data: Dict[str, Any], *a: Any) -> None:
+        if data['response'] != 'y':
+            return
+        for tab in self.all_tabs:
+            if tab.id == tab_id:
+                break
+        else:
+            return
+        for window in tab:
+            self.close_window(window)
 
     def toggle_fullscreen(self) -> None:
         toggle_fullscreen()

kitty/config_data.py

@@ -783,7 +783,7 @@ Note that this does not currently work on Wayland.
 '''))
 
 o('confirm_os_window_close', 0, option_type=positive_int, long_text=_('''
-Ask for confirmation when closing an OS window that has at least this
+Ask for confirmation when closing an OS window or a tab that has at least this
 number of kitty windows in it. A value of zero disables confirmation.
 This confirmation also applies to requests to quit the entire application (all
 OS windows, via the quit action).