bpo-26915: Test identity first in index() and count() of collections.abc.Sequence (GH-553)
diff --git a/Lib/_collections_abc.py b/Lib/_collections_abc.py
index b172f3f..005d884 100644
--- a/Lib/_collections_abc.py
+++ b/Lib/_collections_abc.py
@@ -908,7 +908,8 @@
i = start
while stop is None or i < stop:
try:
- if self[i] == value:
+ v = self[i]
+ if v is value or v == value:
return i
except IndexError:
break
@@ -917,7 +918,7 @@
def count(self, value):
'S.count(value) -> integer -- return number of occurrences of value'
- return sum(1 for v in self if v == value)
+ return sum(1 for v in self if v is value or v == value)
Sequence.register(tuple)
Sequence.register(str)
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index 87454cc..47f7562 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -1310,20 +1310,29 @@
class CustomEqualObject:
def __eq__(self, other):
return False
- class CustomSequence(list):
- def __contains__(self, value):
- return Sequence.__contains__(self, value)
+ class CustomSequence(Sequence):
+ def __init__(self, seq):
+ self._seq = seq
+ def __getitem__(self, index):
+ return self._seq[index]
+ def __len__(self):
+ return len(self._seq)
nan = float('nan')
obj = CustomEqualObject()
+ seq = CustomSequence([nan, obj, nan])
containers = [
- CustomSequence([nan, obj]),
+ seq,
ItemsView({1: nan, 2: obj}),
ValuesView({1: nan, 2: obj})
]
for container in containers:
for elem in container:
self.assertIn(elem, container)
+ self.assertEqual(seq.index(nan), 0)
+ self.assertEqual(seq.index(obj), 1)
+ self.assertEqual(seq.count(nan), 2)
+ self.assertEqual(seq.count(obj), 1)
def assertSameSet(self, s1, s2):
# coerce both to a real set then check equality
diff --git a/Misc/NEWS b/Misc/NEWS
index 1fb7836..7a03a2d 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -16,6 +16,9 @@
Library
-------
+- bpo-26915: index() and count() methods of collections.abc.Sequence now
+ check identity before checking equality when do comparisons.
+
- bpo-29615: SimpleXMLRPCDispatcher no longer chains KeyError (or any other
exception) to exception(s) raised in the dispatched methods.
Patch by Petr Motejlek.