Clean up correctly when a window is closed.

qutebrowser/keyinput/modeman.py

@@ -23,6 +23,8 @@
     manager: The ModeManager instance.
 """
 
+import functools
+
 from PyQt5.QtGui import QWindow
 from PyQt5.QtCore import pyqtSignal, QObject, QEvent
 from PyQt5.QtWidgets import QApplication
@@ -60,6 +62,9 @@ def init(win_id, parent):
         KM.yesno: modeparsers.PromptKeyParser(win_id, modeman),
     }
     objreg.register('keyparsers', keyparsers, scope='window', window=win_id)
+    modeman.destroyed.connect(
+        functools.partial(objreg.delete, 'keyparsers', scope='window',
+                          window=win_id))
     modeman.register(KM.normal, keyparsers[KM.normal].handle)
     modeman.register(KM.hint, keyparsers[KM.hint].handle)
     modeman.register(KM.insert, keyparsers[KM.insert].handle, passthrough=True)

qutebrowser/utils/objreg.py

@@ -23,7 +23,9 @@
 import collections
 import functools
 
-from PyQt5.QtCore import QObject
+from PyQt5.QtCore import QObject, QTimer
+
+from qutebrowser.utils import log
 
 
 class UnsetObject:
@@ -68,12 +70,24 @@ def __setitem__(self, name, obj):
         super().__setitem__(name, obj)
 
     def on_destroyed(self, name):
+        """Schedule removing of a destroyed QObject.
+
+        We don't remove the destroyed object immediately because it might still
+        be destroying its children, which might still use the object
+        registry.
+        """
+        log.misc.debug("schedule destroyed: {}".format(name))
+        QTimer.singleShot(0, functools.partial(self._on_destroyed, name))
+
+    def _on_destroyed(self, name):
         """Remove a destroyed QObject."""
+        log.misc.debug("destroyed: {}".format(name))
         try:
             del self[name]
         except KeyError:
             pass
 
+
     def dump_objects(self):
         """Dump all objects as a list of strings."""
         lines = []

qutebrowser/widgets/completion.py

@@ -94,7 +94,7 @@ def __init__(self, win_id, parent=None):
         super().__init__(parent)
         self._win_id = win_id
         objreg.register('completion', self, scope='window', window=win_id)
-        completer_obj = completer.Completer(win_id)
+        completer_obj = completer.Completer(win_id, self)
         objreg.register('completer', completer_obj, scope='window',
                         window=win_id)
         self.enabled = config.get('completion', 'show')

qutebrowser/widgets/mainwindow.py

@@ -72,6 +72,7 @@ class MainWindow(QWidget):
 
     def __init__(self, win_id, parent=None):
         super().__init__(parent)
+        self.setAttribute(Qt.WA_DeleteOnClose)
         self._commandrunner = None
         self.win_id = win_id
         self.registry = objreg.ObjectRegistry()

qutebrowser/widgets/statusbar/prompt.py

@@ -19,6 +19,8 @@
 
 """Prompt shown in the statusbar."""
 
+import functools
+
 from PyQt5.QtCore import pyqtSignal
 from PyQt5.QtWidgets import QHBoxLayout, QWidget, QLineEdit
 
@@ -69,6 +71,9 @@ def __init__(self, win_id, parent=None):
         prompter_obj = prompter.Prompter(win_id)
         objreg.register('prompter', prompter_obj, scope='window',
                         window=win_id)
+        self.destroyed.connect(
+            functools.partial(objreg.delete, 'prompter', scope='window',
+                              window=win_id))
 
     def __repr__(self):
         return utils.get_repr(self)

qutebrowser/widgets/tabbedbrowser.py

@@ -113,6 +113,9 @@ def __init__(self, win_id, parent=None):
         dispatcher = commands.CommandDispatcher(win_id)
         objreg.register('command-dispatcher', dispatcher, scope='window',
                         window=win_id)
+        self.destroyed.connect(
+            functools.partial(objreg.delete, 'command-dispatcher',
+                              scope='window', window=win_id))
         self._now_focused = None
         # FIXME adjust this to font size
         self.setIconSize(QSize(12, 12))