More fixes for #3102

celery/datastructures.py

@@ -601,8 +601,7 @@ class LimitedSet(object):
     You can also configure minlen, which is the minimal residual size
     of the set.
 
-    All  arguments are optional, with exception of minlen, which must
-    be smaller than maxlen.  Unconfigured limits will not be enforced.
+    All arguments are optional, and no limits are enabled by default.
 
     :keyword maxlen: Optional max number of items.
 
@@ -611,11 +610,13 @@ class LimitedSet(object):
 
     :keyword expires: TTL for all items.
 
-        Items aging over expiration are purged as keys are inserted.
+        Expired items are purged as keys are inserted.
 
     :keyword minlen: Minimal residual size of this set.
         .. versionadded:: 4.0
 
+        Value must be less than ``maxlen`` if both are configured.
+
         Older expired items will be deleted, only after the set
         exceeds minlen number of items.
 
@@ -693,7 +694,9 @@ class LimitedSet(object):
             self.purge()
 
     def update(self, other):
-        """Update this LimitedSet from other LimitedSet, dict or iterable."""
+        """Update this set from other LimitedSet, dict or iterable."""
+        if not other:
+            return
         if isinstance(other, LimitedSet):
             self._data.update(other._data)
             self._refresh_heap()
@@ -701,7 +704,7 @@ class LimitedSet(object):
         elif isinstance(other, dict):
             # revokes are sent as a dict
             for key, inserted in items(other):
-                if isinstance(inserted, list):
+                if isinstance(inserted, (tuple, list)):
                     # in case someone uses ._data directly for sending update
                     inserted = inserted[0]
                 if not isinstance(inserted, float):
@@ -720,7 +723,6 @@ class LimitedSet(object):
         # mark an existing item as removed. If KeyError is not found, pass.
         entry = self._data.pop(item, sentinel)
         if entry is not sentinel:
-            entry[-1] = sentinel
             if self._heap_overload > self.max_heap_percent_overload:
                 self._refresh_heap()
     pop_value = discard
@@ -794,6 +796,10 @@ class LimitedSet(object):
         return self.__class__, (
             self.maxlen, self.expires, self.as_dict(), self.minlen)
 
+    def __bool__(self):
+        return bool(self._data)
+    __nonzero__ = __bool__  # Py2
+
     @property
     def _heap_overload(self):
         """Compute how much is heap bigger than data [percents]."""

celery/tests/utils/test_datastructures.py

@@ -233,7 +233,7 @@ class test_LimitedSet(Case):
         self.assertEqual(s.minlen, len(s))
         self.assertLessEqual(
             len(s._heap),
-            s.maxlen * (100. + s._MAX_HEAP_PERCENTS_OVERLOAD) / 100,
+            s.maxlen * (100. + s.max_heap_percent_overload) / 100,
         )
 
     def test_pickleable(self):
@@ -314,13 +314,12 @@ class test_LimitedSet(Case):
 
     def test_iterable_and_ordering(self):
         s = LimitedSet(maxlen=35, expires=None)
-        for i in reversed(range(15)):
+        for i in range(15):
             s.add(i)
-        j = 40
-        for i in s:
-            self.assertLess(i, j)  # each item is smaller and smaller
-            j = i
-        self.assertEqual(i, 0)  # last item = 0
+        # NOTE: This test used to reverse the input numbers, but
+        # timestamps do not have enough precision to keep the data
+        # ordered when inserted quickly.
+        self.assertEqual(list(s), list(range(15)))
 
     def test_pop_and_ordering_again(self):
         s = LimitedSet(maxlen=5)