Merge pull request #2962 from ales-erjavec/fixes/controlled-list-memleak

[FIX] gui.ControlledList: Take a weakref to listBox

Orange/widgets/gui.py

@@ -8,6 +8,7 @@
 import itertools
 import warnings
 import logging
+import weakref
 from types import LambdaType
 from collections import defaultdict, Sequence
 
@@ -2063,7 +2064,14 @@ class ControlledList(list):
     """
     def __init__(self, content, listBox=None):
         super().__init__(content if content is not None else [])
-        self.listBox = listBox
+        # Controlled list is created behind the back by gui.listBox and
+        # commonly used as a setting which gets synced into a GLOBAL
+        # SettingsHandler and which keeps the OWWidget instance alive via a
+        # reference in listBox (see gui.listBox)
+        if listBox is not None:
+            self.listBox = weakref.ref(listBox)
+        else:
+            self.listBox = lambda: None
 
     def __reduce__(self):
         # cannot pickle self.listBox, but can't discard it
@@ -2073,7 +2081,7 @@ def __reduce__(self):
 
     # TODO ControllgedList.item2name is probably never used
     def item2name(self, item):
-        item = self.listBox.labels[item]
+        item = self.listBox().labels[item]
         if isinstance(item, tuple):
             return item[1]
         else:
@@ -2082,12 +2090,12 @@ def item2name(self, item):
     def __setitem__(self, index, item):
         def unselect(i):
             try:
-                item = self.listBox.item(i)
+                item = self.listBox().item(i)
             except RuntimeError:  # Underlying C/C++ object has been deleted
                 item = None
             if item is None:
                 # Labels changed before clearing the selection: clear everything
-                self.listBox.selectionModel().clear()
+                self.listBox().selectionModel().clear()
             else:
                 item.setSelected(0)
 
@@ -2098,15 +2106,15 @@ def unselect(i):
             for i in self[index]:
                 unselect(i)
             for i in item:
-                self.listBox.item(i).setSelected(1)
+                self.listBox().item(i).setSelected(1)
         super().__setitem__(index, item)
 
     def __delitem__(self, index):
         if isinstance(index, int):
-            self.listBox.item(self[index]).setSelected(0)
+            self.listBox().item(self[index]).setSelected(0)
         else:
             for i in self[index]:
-                self.listBox.item(i).setSelected(0)
+                self.listBox().item(i).setSelected(0)
         super().__delitem__(index)
 
     def append(self, item):
@@ -2116,15 +2124,15 @@ def append(self, item):
     def extend(self, items):
         super().extend(items)
         for i in items:
-            self.listBox.item(i).setSelected(1)
+            self.listBox().item(i).setSelected(1)
 
     def insert(self, index, item):
         item.setSelected(1)
         super().insert(index, item)
 
     def pop(self, index=-1):
         i = super().pop(index)
-        self.listBox.item(i).setSelected(0)
+        self.listBox().item(i).setSelected(0)
 
     def remove(self, item):
         item.setSelected(0)