address requested changes

- syntax cleanup
- use attr.ib when declaring class attributes
- remove unnecessary comments
- code simplification

qutebrowser/browser/browsertab.py

@@ -106,7 +106,7 @@ class TabData:
     override_target = attr.ib(None)
     pinned = attr.ib(False)
     fullscreen = attr.ib(False)
-    input_mode = usertypes.KeyMode.normal
+    input_mode = attr.ib(usertypes.KeyMode.normal)
 
 
 class AbstractAction:

qutebrowser/mainwindow/tabbedbrowser.py

@@ -643,6 +643,9 @@ class TabbedBrowser(tabwidget.TabWidget):
     @pyqtSlot(int)
     def on_current_changed(self, idx):
         """Set last-focused-tab and leave hinting mode when focus changed."""
+        mode_on_change = config.val.tabs.mode_on_change
+        modes_to_save = [usertypes.KeyMode.insert,
+                         usertypes.KeyMode.passthrough]
         if idx == -1 or self.shutting_down:
             # closing the last tab (before quitting) or shutting down
             return
@@ -651,11 +654,9 @@ class TabbedBrowser(tabwidget.TabWidget):
             log.webview.debug("on_current_changed got called with invalid "
                               "index {}".format(idx))
             return
-        if self._now_focused and config.val.tabs.mode_on_change == 'restore':
+        if self._now_focused is not None and mode_on_change == 'restore':
             current_mode = modeman.instance(self._win_id).mode
-            # only save insert & passthrough mode. otherwise default to normal
-            modes = (usertypes.KeyMode.insert, usertypes.KeyMode.passthrough)
-            if current_mode not in modes:
+            if current_mode not in modes_to_save:
                 current_mode = usertypes.KeyMode.normal
             self._now_focused.data.input_mode = current_mode
 
@@ -663,12 +664,11 @@ class TabbedBrowser(tabwidget.TabWidget):
         tab.setFocus()
 
         modes_to_leave = [usertypes.KeyMode.hint, usertypes.KeyMode.caret]
-        if not config.val.tabs.mode_on_change == 'persist':
-            modes_to_leave += [usertypes.KeyMode.insert,
-                               usertypes.KeyMode.passthrough]
+        if mode_on_change != 'persist':
+            modes_to_leave += modes_to_save
         for mode in modes_to_leave:
             modeman.leave(self._win_id, mode, 'tab changed', maybe=True)
-        if config.val.tabs.mode_on_change == 'restore':
+        if mode_on_change == 'restore':
             modeman.enter(self._win_id, tab.data.input_mode,
                           'restore input mode for tab')
         if self._now_focused is not None: