From: Raymond Hettinger <python@rcn.com>
Date: Thu, 13 Dec 2007 00:08:37 +0000 (+0000)
Subject: Fix bug 1604. deque.__init__() did not clear existing contents like list.__init__... 
X-Git-Tag: v2.6a1~879
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=adf9ffdfbe0fb00f5a47444c1dc53eb280d0bd0a;p=python

Fix bug 1604. deque.__init__() did not clear existing contents like list.__init__. Not a backport candidate.
---

diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py
index aeb6d17d5f..e0ca746cd0 100644
--- a/Lib/test/test_deque.py
+++ b/Lib/test/test_deque.py
@@ -29,8 +29,8 @@ class MutateCmp:
 class TestBasic(unittest.TestCase):
 
     def test_basics(self):
-        d = deque(xrange(100))
-        d.__init__(xrange(100, 200))
+        d = deque(xrange(-5125, -5000))
+        d.__init__(xrange(200))
         for i in xrange(200, 400):
             d.append(i)
         for i in reversed(xrange(-200, 0)):
@@ -451,8 +451,8 @@ class DequeWithBadIter(deque):
 class TestSubclass(unittest.TestCase):
 
     def test_basics(self):
-        d = Deque(xrange(100))
-        d.__init__(xrange(100, 200))
+        d = Deque(xrange(25))
+        d.__init__(xrange(200))
         for i in xrange(200, 400):
             d.append(i)
         for i in reversed(xrange(-200, 0)):
diff --git a/Misc/NEWS b/Misc/NEWS
index 679f1fe3ce..7dae508ec2 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -881,6 +881,10 @@ Library
 Extension Modules
 -----------------
 
+- Bug #1604: collections.deque.__init__(iterable) now clears any prior contents
+  before adding elements from the iterable.  This fix brings the behavior into
+  line with that for list.__init__().
+
 - Added wide char functions to msvcrt module: getwch, getwche, putwch and
   ungetwch. The functions accept or return unicode.
 
diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index e5c3218212..9efbc27ae0 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -843,6 +843,7 @@ deque_init(dequeobject *deque, PyObject *args, PyObject *kwdargs)
 		}
 	}
 	deque->maxlen = maxlen;
+	deque_clear(deque);
 	if (iterable != NULL) {
 		PyObject *rv = deque_extend(deque, iterable);
 		if (rv == NULL)